5586 5590.output
TRANSCRIPT
* GB785994 (A)
Description: GB785994 (A) ? 1957-11-06
Improved fluid coking process
Description of GB785994 (A)
PATENT SPECIFICATION 7,
Datet of Application andfiling Complete Specietiatfion:
July 22, 1955 No 21320155.
Application made in United States of America on Aug 23, 1954.
(Patent of Addition to No, 752,400, dated May 20, 1954).
Complete Specification P'ubiihed: Nov 6, 1957.
Index at Acceptance:-Classes 32, E 2; and 55 ( 1), AK( 1: 2: 6 A: 6
B).
International Classification:-l Ob, g.
COMPLETE SPECIFICATION.
Improved Fluid Coking Process.
We, Esso RESEARCH AND ENGINEERING Comp ANY, a corporation duly
organized and existing under the laws of the State of Delaware, United
States of America, having an office at Elizabeth, New Jersey, United
States of America, do hereby declare the invention, for which we pray
that a patent may be granted to us, and the method by which it is to
be performed, to be particularly described in and by the following
statement:
This invention relates to a process for converting hydrocarbons, and
more particularly to coking of heavy residual oils by the fluidized
solids technique Specifically, this invention is concerned with an
improved hydrocarbon oil fluid coking process wherein a coking charge
stock is contacted at a coking temperature with a body of coke
particles maintained in a fluidized state in a coking zone.
Fluid coking processes in which an oil is pyrolytically upgraded by
contact at a coking temperature with particulate solids maintained in
a fluidized state in a coking vessel are well known Upon contact with
the solids, the oil undergoes pyrolysis, evolving lighter hydrocarbons
and depositing carbonaceous residue on the solid particles causing
them to grow in size The necessary heat for the pyrolysis is supplied
by circulating a stream of the fluidized solids through an external
heating zone e g, a combustion zone, and back to the coking vessel.
Because more coke is produced by the coking process than is required
to be burnt to supply heat, the heat-carrying solids will continue to
grow in size because of the carbon deposition and a portion of the
solids must be withdrawn to maintain the total mass or weight
inventory of the particles substantially constant It is customary in
commercial processes to withdraw some of the coke from the system,
comminute the lPrice 3 s 6 d l coke in some manner to form seed coke
or growth nuclei and to return the seed coke to the process to
maintain the particle size and particle size distribution relatively
constant.
This size reduction of solids may be accomplished, for example, by jet
attrition grinding.
The net coke product of the process may be classified as by
elutriation such that only relatively coarse material is withdrawn
whereby the coke of seed size in the process is conserved.
Serious problems have been encountered in the development of this type
of coking.
One problem in particular is the building up of coke deposits on the
confines of the vapor space above the fluidized bed These deposits
cause the pressure drop through the coker and overhead lines to
increase to such an extent as to require the coker to be shut down
periodically and cleaned out.
As the vapors leaving the coking bed are at or near their dew-point,
(i e, their condensation-point), they will readily condense.
This condensation is aided by endothermic polymerization and
condensation reactions occurring in the vapor phase It has been found
that if this condensation of the coker vapors is on surfaces having a
temperature of about 700 to 1000 F, severe coke deposition occurs.
It had not been appreciated heretobefore that entrained solids from
the coking bed, if present above a critical level in the coker product
vapors, prevent coke deposition and fouling in the overhead system of
the coking reactor The present invention is based on the discovery
that by proper control of the operating conditions of a coking
process, partly by control of the particle size, particlesize
distribution and fluidization gas velocities, solid particle
entrainment rates from the fluid bed can be controlled, and by
controlling the entrainment rate and holding it 85,994 so 4 S rd
785,994 above a certain critical minimum, coke deposition is
substantially eliminated.
Specifically, it has now been found that coke deposition on the
interior surfaces of the coking vessel above the fluid bed can be
greatly inhibited or substantially eliminated by maintaining, in the
vapors in the part of the vessel above the fluidized bed, entrained
solids from the fluid coking bed in amounts above a certain critical
minimum, specifically, above 400 lbs /bbl of coking charge stock.
Entrained solids in amounts above this critical level help to uphold
the temperature of the vapors and scour attendant surfaces, thereby
removing carbon deposits and providing surfaces upon which condensing
vapors are absorbed.
According to the present invention, there is provided a hydrocarbon
oil conversion process of the type in which a coking chargestock is
contacted with particulate solids maintained at a coking temperature
as a dense fluidized bed in a coking vessel to obtain relatively
lighter hydrocarbon vapors in the part of the vessel above the
fluidized bed from the upper surface of the bed and thence from the
coking vessel; characterized in that there is'maintained in the said
hydrocarbon vapors an entrainment of the solids 3 i 5 of above 400 lbs
Ibbl of the charge stock.
The hydrocarbon oil which forms the coking charge stock of the present
process is preferably a low value high-boiling residuum of about -10
to 200 A Pl gravity, about 5 33 to 50 wt % Conradson carbon, and
boiling above about 9000 to 12000 F Broadly, however, any hydrocarbon
oil may be treated in the present process, including shale oils, tars,
asphalts, oils derived from coals, synthetic oils, recycled heavy ends
from the coker effluent, whole crudes, heavy distillate and residual
fractions therefrom, or mixtures thereof.
The nature of the present invention will more clearly appear during
the following description of the drawings attached to and forming a
part of this Specification In the drawings, Figure 1 schematically
presents a preferred hydrocarbon oil fluid coking process adapted to
achieve the objects of this invention Figures 2, 3 and 4 are graphical
presentations of data illustrating this invention and its advantages.
Referring to Figure 1, the major items of equipment shown are a coking
vessel 1 and a combustion vessel or burner 2 used to supply heat to
the process The fluid coker 1 contains a fluidized bed of high
temperature solids having an upper level L Preferably, the solids used
in the coking process are finely divided coke particles produced by
the process Other solids such as sand, spent catalyst, or pumice, may
however, be used In this particular coking vessel design, the lower
portion 1-A of the vessel serves as a stripping zone The intermediate
portion, 1-B, is conical in shape so as to minimize the consumption of
fluidizing gas by permitting conversion products generated in the
lower portion of the coker to serve as fluidizing 70 gas in the upper
portions The upper portion 1-C is made narrower so as to increase the
velocity of the vapors withdrawn overhead thereby decreasing secondary
vapor phase cracking of the products As 75 will later appear, the
extent of reduction in the cross-sectional area of the coker at this
point is an important design consideration, as the velocities of the
vapors affect the solid entrainment rate 80 The oil to be upgraded,
such as a vacuum residuum, is injected into the vessel at a plurality
of points via line 3 The feed rate is preferably maintained at a rate
between to 150 bblldy/ft 2 of reactor cross 85 section area at the
upper level of the bed.
The oil undergoes pyrolysis at a temperature in the range of 850 ' to
16000 F, preferably 950 to 10500 F When gas oils for catalytic
cracking are desired, the coker is operated 90 at a temperature in the
range of 9500 to 10500 F When lighter products are desired, e.g,
naphthas and heating oils, the operating temperature is about 1050 to
1200 ' F and when chemicals and chemical intermediates A)5 are
desired, the temperature is 1200 ' to 16000 F, preferably 1300 ' to
1450 ̂F.
Steam is admitted to the base of the vessel as by line 4 This steam
serves first to strip the coke particles before the coke is circulated
11)0 to the burner and then passes upwardly through the vessel
fluidizing the solids therein The reaction products are taken off
overhead by line 5 after having entrained solids removed by cyclone 6
and may be 105 further processed, as desired.
In order to supply heat to the process, solids are circulated from the
base of the coking vessel by line 7 to a burner vessel 2.
Here the particles are fluidized by an oxi 110 dizing gas, e g, air,
supplied by line 8 The resulting combustion heats the particles to a
temperature 1000 to 3000 F higher than the coking temperature After
having entrained solids removed, flue gases are removed 115 overhead
from the burner vessel by line 9 and may be vented to the atmosphere.
Heated solids are transferred to the fluid coker by line 10 Other
means may, of course, be used to reheat the coke particles 120
including gravitating bed burners, transfer line burners, shot heating
systems, and other direct and indirect heating means Line 11 removes
from the coking vessel the net coke product and agglomerates produced
by the 125 process.
Coking deposits will normally form in the coking vessel on the
surfaces above the fluid bed level L including the surfaces of cyclone
6 and overhead line 5 unless steps are taken 130 have to be operated
at capacities less than maximum A preferred method of controlling the
superficial gas velocity is to control the level L of the fluid bed
along a tapered portion of the reactor as shown 70 By increasing the
amount of coke hold-up in the reactor, the level L will move upwardly
along this tapered portion and consequently the cross-sectional area
of the surfaces of the fluid bed will be decreased 75 Thus the
fluidizing gas velocity through this surface will be increased and the
entrainment rate will thereby be increased The extent of this taper
is, of course, a design consideration and can be made to provide for a
80 fairly wide range of operating conditions.
By proper design, the reactor may be configured to achieve an
entrainment rate of over 4-00 lbs of coke /bbl of feed without the
necessity of resorting to any special control 85 techniques.
So far as it is known, it is believed that the entrainment from a
fluid bed with a given particle size and superficial gas velocity and
the amount of solids entrained in withdrawn 90 vapors is substantially
independent of the reactor geometry or configuration at the top or
above the fluid bed with the exception of reactor outage Outage is the
distance from the surface of the fluid bed to the cyclone 95 outlet,
indicated by the dimension 0 on the drawing As the outage is
increased, the amount of solids contained in the vapors in the
uppermost portions of the reactor will be decreased 109) Figure 3
shows in simplified relations a method of controlling the entrainment
rate.
Although the coke particle size used in fluid coking may vary up to
1000 microns or more, the preferred particle size is within the range
105 of 40-500 microns, with 200-300 microns being the median particle
size The particle distribution may vary within these ranges.
The preferred particle distribution is such that 10 to 20 wt % of the
coke is smaller 110 than 147 microns, 30 to 60 wt % is smaller than
175 microns, 60 to 90 wt % is smaller than 246 microns and O to 5 wt %
is no larger than 400 microns This particle size and distribution are
controlled by controlling 115 the rate and size of seed coke additions
and coke product withdrawal The coke particles normally have a true
particle density in the range of 90 to 110 lbs /ft 3 For material this
size, the superficial gas veloci 120 ties in the reactor will lie in
the range of 1-5 ft /sec and bed densities will be in the range of 30
to 55 lbs Ift 3.
For a fluid coking vessel operating under normal coking conditions, e
g, temperature 125 9500 F, pressure 6 ' psig, fluidizing steam wt %
based on feed, coke circulation rate to burner 15 lbs /lb of feed, a
chart in the nature of Figure 3 may be prepared Figure 3 relates feed
rate in bbls /day /sq ft of cross 133 to prevent their formation This
invention is directed primarily towards tile prevention of coking
between the fluid bed level L and the inlet C, to the cyclone,
although operation in accordance with the present invention will
substantially reduce coking of the equipment beyond inlet C It is in
this area between L and C where the greatest amount of coke deposition
occurs in normal coking operations.
In some coking processes, the solid-; separating means, i e, cyclone,
is located outside the coking reactor The present invention is also
applicable to such designs.
According to the present invention, the superficial velocity of the
vapors, which comprises reaction products and fluidizing gas, through
the upper surfaces L of the fluid bed is regulated to obtain an
entrainment above 400 lbs /bbl of stock charged to the coker By
maintaining this entrainment rate, coking of the equipment is
substantially prevented.
The criticality of maintaining a certain 2.5 entrainment rate will be
appreciated by reference to Figure 2, which presents data obtained
from a fluid cokier operating under conventional conditions The
abscissa of Figure 2 indicates the increase in pressure drop from the
level L of the fluid bed through the cyclone outlet due to coking and
fouling in a coking vessel, as related to the amount of solids
entrained in the vapors withdrawn overhead As can readily be seen,
coking of equipment is virtually nonexistent when the entrainment rate
is above 400 lbs Ibbl.
of feed When the entrainment rate is less than 400 lbs Ibbl, then the
increase in pressure drop due to coking increases almost exponentially
with decreases in entrainment rate The figure also shows that there is
no practical advantage obtained by maintaining the entrainment rate
above 800 lbs of solids Ibbl of feed.
The entrainment rate of solids from the fluid bed is controlled
primarily by control of the superficial fluidized gas velocity.
Attention must be paid, however, to the particle size and size
distribution of the ao fluidized coke For a relatively coarse
material, fluidizing gas velocity will have to be higher to obtain a
given entrainment as opposed to the use of a finer material.
The fluidizing gas velocity may be controlled by various methods The
amount of fluidizing steam or other inert gases used may, of course,
be controlled to regulate the superficial gas velocity Excessive use
of fluidizing gas is to be avoided, however, as it results in
uneconomical operation The rate of feed injection into the coking
vessel may also be controlled so as to control fluidizing gas velocity
This method of control per se is not too attractive as it may mean in
some instances that the coker will 785,994 sectional area of the
reactor to the entrainment rate in lbs /bbl of feed which is dependent
upon the superficial gas velocity and size distribution of the coke in
the figure Wt %, retained on 80 mesh is used in the chart as being
indicative of the size distribution of the coke Thus, for a set of
conditions, the fluidizing gas velocity necessary to obtain the
minimum entrainment needed to avoid colke deposition can be obtained
from Figure 3 following lines X Y and Z in the direction indicated.
A commercial fluid coker majy be designed to provide sufficient gas
velocity in the top of the reactor to give sufficient entrainment
under normal conditions It is quite possible, however, that a coking
unit may be called upon to operate at widely varying feed rates For
example, the unit may process 10,000 B /D of oil in the winter and yet
only be required to handle 4000 B ID in the summer At the lower feed
rate, the gas velocity in the top of the reactor will be greatly
reduced This would mean that unless special operating controls were
invoked, the entrainment rate would become dangerously low, leading to
coke deposits in the top of the reactor followed by a shut down of the
unit By use of a plot similar to Figure 3, however, proper entrainment
can be maintained As the feed rate is reduced, both the velocity and
the particle size of the circulating coke can be varied to hold the
entrainment above 400 lbs Ibbl of feed Velocity can be adjusted by
increasing the quantity of fluidizing gas and by controlling the
position of the surface of the fluid bed with respect to upper tapered
portion of the reactor, if the reactor be so designed The particle
size and distribution can be varied by adjusting the amount and size
of seed coke or growth nuclei added to the system.
For example, with reference to Figure 3, a coking reactor may normally
handle an B /D Ift 2 of reactor cross-section, of feed.
The entrainment at this rate may be desired to be about 600 lbs Ibbl
of feed The lines X'., Y 1 and Z 1 on Figure 3 represent the
conditions necessary to maintain the desired entrainment If the feed
rate becomes Bl D Ift 2, then the entrainment will drop below the
minimum for safe operation, even though this decrease is partially
compensated for by a decrease in particle size, as indicated by lines
X, Yll and Z 11 But by a change both in gas velocity and in particle
size, as indicated by lines X, Y and Z, the entrainment can be brought
back to the desired 600 lbs /bbl.
Figure -3 was based upon a coking vessel having about 11 ft outage
Figure 4 illustrates a method that may be used to extrapolate the data
of Figure 3 to a coking vessel having a different " outage ' The
abscissa of Figure 4 indicates the outane in feed and the ordinate
Yields a multiplies which can be used to adjust the curves in the left
field of Figure 2 upwardly or downwardly.
It should be understood that the Figures 3 74 and 4 havle been used
only to illustrate one method of controlling and determining the
entrainment rate and this invention is not to be limited thereby Other
methods may wvell be used It is important however, that 7 athe
entrainment in the vapors withdrawn overhead be above 400 lbs /bbl of
feed.
Solids entrained according to this invention are most beneficial in
preventing coke deposits before the cyclone inlet However a coke
deposition in the cyclone and beyond is also inhibited because the
high entrainment minimizes temperature drop and, therefore.
inhibits condensation of the vapors The solids also absorb any
condensate and poly 85 meric material formed from the vapors The
entrained solids will also provide a scouring action in the cyclone
and, due to some coke losses through the cyclone, will scour the lines
after the cyclone 90
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* Last updated: 08.04.2015
* Worldwide Database
* 5.8.23.4; 93p
* GB785995 (A)
Description: GB785995 (A) ? 1957-11-06
Improvements in or relating to the preparation of titanium carbide, boride
or nitride
Description of GB785995 (A)
A high quality text as facsimile in your desired language may be available
amongst the following family members:
DE1038018 (B)
DE1038018 (B) less
Translate this text into Tooltip
[78][(1)__Select language]
Translate this text into
The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
r
PATENT SPECIFICATION
785,995 Date of Application and filing Complete Specification: Aug 11,
1955.
No 23229/55.
Application made in United States of America on Aug 16, 1954.
Complete Specification Published: Nov 6, i 957.
Pam 78 >.Cv Ii ICXT OJ, NO 73 'D, 98 Re erence as been -e A Pursu oeh
Pae A Ct, 1949 t Oe Pearrednt 2 c 'T d 77-j 11;S 2 r a Th: PAT 2 INT O
FF 10, igth Yl:zrch, 19 D L' O 5446/1 ( 4)/a D 8 g 150 //ES for making
titanium and more especially to an improvement in the method of
forming a starting composition from which said titanium compounds may
be formed.
An object of the present invention is to provide an improved method
for forming a homogeneous mixture of titanium hydrate, titanium
phosphate or alkali altered titanium hydrate and carbon particles for
use in the preparation of said titanium compounds.
The invention provides a starting composition for the preparation of
titanium carbide, boride or nitride comprising an intimate mixture of
titanium hydrate, titanium phosphate or alkali altered titanium
hydrate and carbon particles prepared by precipitating the titanium
hydrate, titanium phosphate or alkali altered titanium hydrate from
aqueous solution in the presence of the carbon particles so that the
titanium hydrate, hydrated titanium phosphate or alkali altered
titanium hydrate and carbon particles are joined by a coalescent bond.
The titanium hydrate is an uncalcined hydrate precipitated usually by
hydrolysis from a salt solution prepared from an acid digest of a
titaniferous material, such as, for example, titaniferous ore, ore
concentrates or slags By way of illustration, the digestion treatment
may comprise mixing a titaniferous material with concentrated ( 93 '
sv/w v) sulphuric acid in an amount such that the ratio of acid,
calculated as 100 % sulphuric acid, to the titaniferous material, on a
Ti O, basis, is precipltateu uv washed.
Although washing serves to remove large amounts of soluble salts and
free acid there is usually some acid present in the form of a basic
salt or adsorbed acid which may impair the quality of the titanium
compounds to be formed therefrom, and hence the hydrate may be treated
with a basic substance, such as alkaline compounds of sodium,
potassium or ammonium to neutralize and/or remove the adsorbed acid In
general, the size of the individual particles, that is to say the
crystalloids or agglomerates of crystalloids of precipitated hydrous
titanium oxide, is within the range of from about 0 01 to 0 5 microns.
For reasons of economy, sulphuric acid solutions of titanium are used
in carrying out the process of the present invention in preference to
solutions prepared from hydrochloric acid.
To prepare the starting composition of this invention using an
unaltered titanium hydrate pulp, finely divided carbon having a
particle size in the range of from 0 005 to 0 01 microns and
preferably hydrophilic, may be added to a titanium sulphate solution
prepared in the manner hereinabove described, prior to hydrolysis,
whereupon the mixture is heated and maintained at a temperature within
the range of about 1000 C to 1120 C for approximately two hours
whereby most of the titanium oxide values in the solution is
hydrolyzed and precipitated out as hydrous Ind Int 8 () t k 11, 1 1 1
1, -"'11 -9 AI 9 A 1)PATENT SPECIFICATION
785 995 Date of Application and filing Complete Specification: Aug I
1, 1955.
No 23229155.
Application made in United States of America on Aug 16, 1954.
Complete Specification Published: Nov 6, 1957.
idex at acceptance:-Class 1 ( 2), E( 1 A 1: 2 A 1: 5 A 1).
iternational Classification:-C Olb.
COMPLETE SPECIFICATION
Improvements in or relating to the preparation of Titanium Carbide,
Boride or Nitride We, NATIONAL LEAD COMPANY, a Corporation organised
and existing under the Laws of the State of New Jersey, United States
of America, of 111, Broadway, New York 6, State of New York, United
States of America, do hereby declare the invention, for which we pray
that a patent may be granted to us, and the method by which it is to
be performed, to be particularly described in and by the following
statement: -
The present invention relates to a process for making titanium
carbide, boride or nitride and more especially to an improvement in
the method of forming a starting composition from which said titanium
compounds may be formed.
An object of the present invention is to provide an improved method
for forming a homogeneous mixture of titanium hydrate, titanium
phosphate or alkali altered titanium hydrate and carbon particles for
use in the preparation of said titanium compounds.
The invention provides a starting composition for the preparation of
titanium carbide, boride or nitride comprising an intimate mixture of
titanium hydrate, titanium phosphate or alkali altered titanium
hydrate and carbon particles prepared by precipitating the titanium
hydrate, titanium phosphate or alkali altered titanium hydrate from
aqueous solution in the presence of the carbon particles so that the
titanium hydrate, hydrated titanium phosphate or alkali altered
titanium hydrate and carbon particles are joined by a coalescent bond.
The titanium hydrate is an uncalcined hydrate precipitated usually by
hydrolysis from a salt solution prepared from an acid digest of a
titaniferous material, such as, for example, titaniferous ore, ore
concentrates or slags By way of illustration, the digestion treatment
may comprise mixing a titaniferous material with concentrated ( 93 %
w/w) sulphuric acid in an amount such that the ratio of acid,
calculated as 100 % sulphuric acid, to the titaniferous material, on a
Ti OQ basis, is within the range of from about 1 3 to 1 5 parts acid
to one part titaniferous material, and heating the mixture until a
reaction sets in and a digestion cake is formed The digestion cake is
then dissolved in water to form a solution to which scrap iron or the
like is added to convert the ferric iron values to ferrous iron The
solution is then clarified, filtered, concentrated and crystallized in
the manner well-known to the art of pigment manufacture to form a
titanium sulphate solution from which the hydrous titanium oxide is
precipitated by hydrolysis and thereafter washed.
Although washing serves to remove large amounts of soluble salts and
free acid, there is usually some acid present in the form of a basic
salt or adsorbed acid which may impair the quality of the titanium
compounds to be formed therefrom, and hence the hydrate may be treated
with a basic substance, such as alkaline compounds of sodium,
potassium or ammonium to neutralize and/or remove the adsorbed acid In
general, the size of the individual particles, that is to say the
crystalloids or agglomerates of crystalloids of precipitated hydrous
titanium oxide, is within the range of from about 0 01 to 0 5 microns.
For reasons of economy, sulphuric acid solutions of titanium are used
in carrying out the process of the present invention in preference to
solutions prepared from hydrochloric acid.
To prepare the starting composition of this invention using an
unaltered titanium hydrate pulp, finely divided carbon having a
particle size in the range of from 0 005 to 0 01 microns and
preferably hydrophilic, may be added to a titanium sulphate solution
prepared in the manner hereinabove described, prior to hydrolysis,
whereupon the mixture is heated and maintained at a temperature within
the range of about 1000 C to 1120 C for approximately two hours
whereby most of the titanium oxide values in the solution is
hydrolyzed and precipitated out as hydrous .f I_ titanium oxide in the
presence of the individual carbon particles Thereby, the individual
particles of hydrous titanium oxide are joined with the individual
carbon particles by a coalescent bond to form a uniform intimate
mixture of the hydrate and carbon.
This mixture is then filtered or otherwise separated from the soluble
salts and acid formed during the hydrolysis, washed and subsequently
dried to provide a starting composition from which titanium carbide,
boride or nitride may be formed as described below, the size of the
particles of the starting composition being for example within the
range of from 0 02 to 0 5 microns.
While the procedure described above is satisfactory, improved yields
of the hydrate may be obtained by the expedient of adding a nucleating
agent to the salt solution at hydrolysis A typical nucleating agent,
sometimes referred to in the art as a yield seed, is that prepared
from a titanium sulphate hydrolysate by treatment of the latter with
an alkali metal hydroxide, such as sodium hydroxide, to form an alkali
altered hydrate.
The thermal hydrolysis of a titanium salt solution, as hereinabove
described, produces a hydrate in the form of metatitanic acid, but it
is within the scope of the invention to form the hydrate as
ortho-titanic acid.
Although a titanium hydrate formed from a titanium sulphate solution,
as hereinabove described is highly satisfactory, hydrated titanium
phosphate or alkali altered titanium hydrate may be used instead Thus,
it is within the scope of the invention to prepare a starting
composition by mixing a dilute aqueous solution of phosphoric acid or
a phosphate and a dilute aqueous titanium salt solution at room
temperature in the presence of finely divided carbon, and then heating
the mixture to complete the reaction and form a filterable starting
compound comprising individual particles of titanium phosphate joined
to the individual carbon particles by a coalescent bond; or by adding
phosphoric acid or a soluble phosphate to the unmodified starting
compositions hereinabove described, thereby to convert the hydrous
titanium oxide component to titanium phosphate in the presence of the
carbon.
It has been found also that the starting composition of this invention
may be formed from a mixture of an alkali altered hydrate and finely
divided carbon particles As used herein, the phrase "alkali altered
hydrate" denotes a material which according to one method is prepared
from an unaltered hydrate, as hereinabove described, by adding thereto
an alkali metal hydroxide, e g, sodium hydroxide, in much the same way
that an alkali metal hydroxide is added to the hydrate to neutralize
the sulphate values, except that in this instance sufficient alkali
metal hydroxide is added not 6 only: to neutralize the sulphate values
but to alter the hydrate itself such that upon calcination it will be
converted to a sodium titanate or mixture of sodium titanates It has
been found that a suitable amount of sodium hydroxide would be
approximately 1 l parts by weight to 1 part by weight of Ti O, As an
alternative method for preparing the alkali altered hydrate, the
latter may be formed in the presence of finely divided carbon, from a
pure titanium salt solution, i e, one which is free of iron and other
impurities by addition of sufficient alkali to the solution to
neutralize all the acid and for the alteration of the hydrate.
A feature which is common to each of the above described starting
compositions is the step by which intimate contact is achieved between
the particles of the hydrated titanium compound and the carbon
particles, in each instance the titanium compound being intimately
joined with the individual carbon particles by formation of the
compound in the presence of the carbon particles.
While the formation of the starting material of this invention by
thermal hydrolysis of a sulphate solution in the presence of carbon
may be carried out successfully at atmospheric pressure, it has been
found that the rate of hydrolysis may be accelerated considerably by
carrying out the operation in an autoclave under pressures of 100 to
500 lbs per square inch Pressure hydrolysis, preferably coupled with
agitation, results in a thorough blending of the titanium compound and
carbon particles in a relatively short time.
The following is a description by way of example of methods of
carrying the invention into effect.
c EXAMPLE I.
To prepare the unmodified starting com 1 ( position of this invention,
a clarified sulphate solution is prepared in a manner well-known in
the art, as for example by digesting a titaniferous ore in
concentrated H 25 04 to form a digest cake which is dissolved in H O,
1 l filtered, clarified, crystallized, and again diluted with H 2 O to
form a solution having a Ti O 2 content of about 200 grams per litre.
To this solution was added finely divided hydrophilic carbon in an
amount which was 11 varied depending upon the titanium compound to be
formed therefrom Thus, when the solution was to be used to prepare
titanium carbide, finely divided hydrophilic carbon was added to the
solution in an amount to satisfy 12 the formula:
Ti O, + 3 C-Ti C + 2 C O based on the amount of titanium, calculated
as Ti O,, recovered from the solution.
A solution prepared in the above manner 12 was boiled for about two
hours in the presence of 1 % yield seed until about 95 % of the
titanium was precipitated out as a titanium 785,995 tion of phosphoric
acid ( 50 grams per litre P 1,0) was added to a titanium sulphate
solution ( 30 grams per litre Ti O,) containing finely divided carbon,
the weight ratio of PO, to the titanium values being 0 6 on a Ti O 2
basis The carbon was present in an amount to satisfy the formula:
Ti P,07 + 8 C= Ti C+ 7 CO + P 2 hydrate intimately associated with the
fine particles of carbon This starting composition was then separated
from the liquid, washed and dried, and subsequently converted to
titanium carbide by calcination.
To this end the starting composition was placed in a furnace and
calcined at a temperature of about 16500 C for about two hours in an
inert atmosphere The resulting product comprised a finely divided
powder, the size of the particles being from 1 to 10 microns An
analysis of the product showed 80.% titanium and 19 5 % carbon.
EXAMPLE II.
To prepare titanium boride starting composition was prepared
substantially in the manner described in Example I except that in this
instance finely divided hydrophilic carbon was added to the sulphate
solution prior to hydrolysis in an amount to satisfy the formula:
Ti Oai + B,0, + 5 G-+Ti B, + 5 C O based on the amount of titanium,
calculated as Ti O, recovered from the solution.
To prepare titanium boride from the resulting starting composition,
130 parts, on a weight basis, of boric acid, as B 0,, were added for
every 148 parts of Ti O 2 in the starting composition, and the mixture
was agitated for a sufficient length of time to thoroughly disseminate
the boric acid therethrough whereupon the mixture was introduced into
a furnace and calcined at a temperature of about 1550 C for about two
hours in an atmosphere of argon.
The resulting product comprised a finely divided powder which analyzed
68 4 % titanium and 29 6 % boron and had an effective particle size of
from 1 to 5 microns.
EXAMPLE III.
To prepare titanium nitride, a starting composition was formed by the
method described in Example I except that in this instance finely
divided hydrophilic carbon was added to the sulphate solution in an
amount to satisfy the formula:
Ti Q, + 2 C+ N->Ti N+ 2 C O based on the amount of titanium,
calculated as Ti O,, recovered from the solution The starting
composition resulting from hydrolysis of this solution was dried and
introduced into a furnace and calcined at a temperature of about 1350
C for about two hours in an atmosphere of nitrogen The resulting
product comprised a finely divided titanium nitride powder which
analyzed 78 6 % titanium and 19.4 % nitrogen, the size of the
particles being from 1 to 15 microns.
EXAMPLE IV.
To prepare titanium carbide from a starting composition comprising
titanium phosphate and hydrophilic carbon, a dilute solubased on the
titanium, calculated as Ti P,01, recovered from the solution This
mixture was heated for one hour at a temperature of about C and
precipitated a starting composition of coalesced titanium phosphate
and carbon which, after being dried, was introduced into a furnace and
calcined at a temperature of about 16000 C for about two hours in an
atmosphere of argon.
The resulting product comprised a finely divided titanium carbide
powder which analyzed 79 1 % titanium and 19 3 % carbon, the particle
size of the product being in the range of from 1 to 10 microns.
EXAMPLE V.
To prepare titanium nitride from a starting composition of coalesced
titanium phosphate and hydrophilic carbon, a starting composition was
prepared substantially in the manner described in Example IV except
that finely divided carbon was added in an amount to satisfy the
formula:
N, Ti P,07 + 7 C Ti N + 7 C O + P.
based on the amount of titanium, calculated as Ti P 50,, recovered
from the solution This starting composition was calcined at a tem 95
perature of about 13500 C for two hours in an atmosphere of nitrogen
The resulting product was a finely divided titanium nitride powder of
substantially uniform particle size, which analyzed 79 % titanium and
21 % 100 nitrogen, the particles ranging in size from about 1 to 10
microns.
EXAMPLE VI.
To form titanium boride a starting composition of titanium phosphate
and hydro 105 philic carbon was prepared as described in Example IV
except that finely divided carbon was added in an amount to satisfy
the formula:
Ti P,0,9 + l OC + B,Q, = Ti B,,,+ l OCO + P 1, based on the amount of
titanium, calculated 110 as Ti O 2, recovered from the solution For
every 148 parts of titanium, calculated as Ti O 2, in the
titanium-phosphate-carbon composition were added 130 parts boric acid
as BO, The mixture was thoroughly agitated for a sufficient 115 length
of time to form intimate contact of the materials whereupon the
mixture was introduced into a furnace and calcined at a temperature of
about 15500 C for about two.
W 8,9 g 5 hours in an atmosphere of argon.
The resulting product comprised finely divided powder which analyzed
68 1 % titanium and 299 % boron, the effective particle size being
from 1 to 5 microns.
As mentioned above, the invention also contemplates the preparation of
a starting composition comprising a mixture of an alkali altered
hydrate and carbon from which the carbide, nitride and boride
metalloids may be produced in the manner described above.
One way in which this alkali altered hydrate-carbon starting
composition may be prepared is by thermal hydrolysis of a sulphate
solution and carbon, in situ, as described in Example I, and then
adding to the resulting hydrate-carbon mixture a quantity of an alkali
metal hydroxide, for example, sodium hydroxide.
The alkali altered hydrate-carbon starting composition may also be
prepared from a pure titanium salt solution, that is to say a solution
free of iron, vanadium, aluminium and other impurities By way of
example, finely divided carbon may be added to a pure chloride
solution, such as titanium tetrachloride, and to this mixture is added
an alkali metal, such as sodium hydroxide, in an amount sufficient
both to neutralize the solution and alter the hydrate The resulting
hydrolysate will comprise an admixture of carbon particles, bonded
with the particles of alkali altered hydrate from which the soluble
salts may be removed by washing prior to calcination.
From the foregoing description and examples it will be evident that
the starting composition of the present invention is a highly reactive
material which may be calcined at relatively low temperatures to form
titanium carbide, boride or nitride of high purity and uniform and
fine particle size.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* Last updated: 08.04.2015
* Worldwide Database
* 5.8.23.4; 93p
* GB785996 (A)
Description: GB785996 (A) ? 1957-11-06
Improvements in and apparatus for injection moulding polymers of halogen-
containing vinyl compounds
Description of GB785996 (A)
COMPLETE SPECIFICATION.
Improvements in and Apparatus for Injection Moulding Polymers of
Halogen- Containing Vinyl Compounds.
We, CHEMISOHE WERKE HULS AXTIEN- GE5ELL5OHAFT, a German Body
Corporate, of 21A Marl, ltreis Becklinghausen, Germany, do hereby
declare the invention, for which we pray that a patent may be granted
to us, and the method by which it is to be performed, to be
particularly described in and by the following statement
It has already been proposed to work up polymers of halogen-containing
vinyl compounds by injection moulding or extrusion pressing by heating
the polymer in an injection-moulding-cyli.nder of an
injection-moulding machine to the temperature necessary for a
satisfactory flow and then extruding it through a nozzle under
pressure into the mould. Hitherto, however, only polymers containing
softeners could be worked up without difficulty because in the case of
polymers free from softener the temperature necessary for a
satisfactory flow is dangerously near to the decomposition
temperature. Therefore when polymers free from softener are wolked up
for injectionmoulding by known methods, account must be taken of
decomposition phenomena, in particular with the formation of hydrogen
chloride, and this on the one hand impairs the value of the injection
moulding and on the other hand endangers the injectionmoulding
apparatus used. The decomposition phenomena can be suppressed by the
addition of considerable amounts of stabilisers but not excluded. If
the temperature necessary for satisfactory flow of the polymer is
reduced by the addition of lubricants, the mechanical values of the
products obtained are worsened.
We have now found that polymers of halogen-containing vinyl compounds
which are free from softener can be injectionmoulded in an
advantageous way by heating the polymer in the
injection-mouldingcylinder to a temperature which is 10 to 20 C. below
the temperature which is necessary for satisfactory flow and producing
the temperature necessary for satisfactory flow by pressing out the
polymer into the mould through a constriction under high pressure. As
a polymer of a halogen-containing vinyl compound, polyvinyl chloride
is especially suitable which can be prepared by emulsion
polymerisation or by suspension polymerisation, and other suitable
compounds are after-chlorinated polyvinyl chloride, polyvinylidene
chloride and copolymers of vinyl chloride and vinylidene chloride with
each other or with other polymerisable compounds. The usual additions
of fillers, dyestuffs, stabilisers and lubricants may be incorporated
with the polymers. Stabilisers are only necessary in amounts smaller
than in the known methods, as for example 0.5 to 3%, or less active
stabilisers, as for example non-toxic stabilisers, can be used the
introduction of which for the injection moulding of polymers free from
softener according to the known methods is impossible.
If desired the addition of lubricants can be entirely dispensed with.
The temperature necessary for satisfactory flow and lying in the
neighbourhood of the decomposition temperature is preferably
ascertained by a preliminary experiment.
The polymer is then heated in the injectionmoulding- cylinder of an
injection-moulding machine, while avoiding overheating, to
temperatures which are 10 to 200 C. below the temperature necessary
for satisfactory flow. This heating is preferably effected in zones,
for example by resistance heating coils wound around the
injection-moulding.
cylinder. For forcing out the heated polymer into the mould through a
constriction, a pressure of more than 1500 kilograms per square
centimetre is required.
The constriction should amount to at least 50% calculated as reduction
in cross-section as compared with the original cross-section.
The length of the constriction should amount to at least half of the
diameter of the original cross-section. If the constriction is slight,
its length must be great. If the constriction is considerable, it is
sufficient for it to have a short length. Since the pressure necessary
for forcing out the polymer increases as the constriction increases,
the constriction has an upper limit placed thereon by the pressure
economically produceable in the apparatus used. The lower limit of the
constriction is provided by the fact that with decreasing constriction
the necessary length soon becomes cumbersome and uneconomical. It is
advantageous to use constrictions of 75 to 95% which have a length
about equal to 4 to 2 times the diameter of the original cposs-
section. From the constriction a stream of polymer is then led in
known manner into the mould which is advantageously preheated to a
temperature of 400 to 600 C.
By working in this way, the polymer is only exposed to the temperature
necessary for a satisfactory flow for a short time, namely from its
passage through the constriction to its entry into the injection
mould. In this way a decomposition and consequent injury to the
polymer and- the apparatus are avoided. It is even possible in this
way to work up polymers of which the temperature necessary for
satisfactory flow coincides with the decomposition temperature.
We have also found that the said process can be carried out
advantageously in an apparatus which consists of an
injectionmoulding-cylinder capable of being heated, preferably in
zones, at the rear end of which is provided a pressure means capable
of applying a pressure of more than 1500 kilograms per square
centimetre and the front end of which is provided with a constriction
which amounts to at least 50% (calculated as reduction in
cross-section as compared with the original cross-section) and which
has a length of at least half the diameter of the original
cross-section. The injeetion-moulding-cylinder is preferably
constructed so that it holds no more than 2 to 3 times the amount of
polymer which is to be used as a maximum in a single
injection-moulding operation. Thus the residence time of the polymer
in the injeetion-moulding-cylinder and consequently the thermal load
is kept small. Usually the pressure means will be a piston which fits
into the injection-moulding-cyiinder. The constriction is preferably
formed by a mern- ber which temporarily splits up the stream of
polymer into a plurality of partial streams.
A torpedo having longitudinal grooves or longitudinal ribs arranged in
the interior of the inj ection-moulding-cylinder is especially
advantageous. The apparatus is preferably made of material which
resists corrosion, as for example from a stainless steel.
An embodiment of apparatus according to the present invention is shown
in the accompanying drawing in which :-
Figure 1 is a sectional elevation; and
Figure 2 is a cross-section on the line a-b.
An injection-moulding-cylinder 1 is provided with resistance heating
coils 4. A pressure means is shown at 2 and the constriction is formed
by a torpedo 5 having longitudinal grooves or ribs which split up the
stream of polymer temporarily into a number of partial streams by
virtue of the shape thereof. The polymer, which is introduced at 6,
passes through the nozzle 3 into an injection mould (not shown).
The ibliowing examples will further illustrate this invention but the
invention is not restricted to these examples.
EXAMPLE 1.
A polyvinyl chloride having a R-value of 55 obtained by suspension
polymerisation is granulated with 2% of lead stearate as stabiliser
and then lvorked up in an injection moulding machine. In the
injection-mould ing-cylinder having an internal diameter of 30
millimetres, the material is heated by electrical resistance heating
coils to 1600 C.
in a first zone, to 1750 C. in a second zone and to 1s0O Cl. in a
third zone. The heated polymer is forced with a pressure of 1600
kilograms per square centimetre through a constriction of 75%
(calculated as reduction as compared with the original cross-section)
having a length of 60 millimetres, and through a nozzle of 2
nijilimetres diameter during the course of 15 seconds into a mould
preheated to 500 C. Test rods from the moulding thus obtained give a
tensile strength of 550 kilograms per square centimetre and a breaking
elongation of 20 to pro%. The mouldings obtained are practically
without discoloration and the apparatus used does not show any
corrosion at all.
EXAZPLE'.
If a suspension polymer of vinyl chloride having the K-value 70 and
stabilised with 2% of an organic sulphur-tin compound is used as
described in Example 1 under a pressure of 1700 kilograms per square
centimetre and a temperature of 170j180 ( 1S5" C., practically
undiscoloured test rods are obtained having a tensile strength of 620
kilograms per square centimetre and a breaking elongation of aO9. In
this case also, the apparatus is not eorroded.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* Last updated: 08.04.2015
* Worldwide Database
* 5.8.23.4; 93p
* GB785997 (A)
Description: GB785997 (A) ? 1957-11-06
Method for the recovery of uranium products from solutions containing
hexavalent uranium
Description of GB785997 (A)
Translate this text into Tooltip
[75][(1)__Select language]
Translate this text into
The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
PATENT SPECIFICATION
785997 : Date of Application and filing Complete Specification: Aug
18, 1955.
No 23845/55.
Application made in Sweden on Aug 20, 1954.
Complete Specification Published: Nov 6, 1957.
Index at acceptance: -Class 1 ( 2), C 3 CXM International
Classification:-CO 1 g.
COMPLETE SPECWIICATION Method for the Recovery of Uranium Products
from Solutions containing Hexavalent Uranium We, A B ATOMENERGI, a
joint stock company organized according to the laws of Sweden, of
Lovholmsvdgen 5, Stockholm 9, Sweden, do hereby declare the invention,
for which we pray that a patent may be granted to us, and the method
by which it is to be performed, to be particularly described in and by
the following statement:-
The conventional method for precipitating uranium from aqueous
solutions containing hexavalent uranium is precipitation by the
addition of ammonium hydroxide, alkali metal hydroxides or alkaline
earth metal hydroxides.
Thereby a product is obtained which is very difficult to separate from
the solution by sedimentation, filtration or centrifuging, whether the
solution contains foreign ions or not Owing to local excess
concentration which cannot be prevented on the addition of the
neutralizing agent the product becomes heavily polluted by
co-precipitation of other ions if such ions are also present in the
solution If the product is later to be subjected to processes in the
dry state it will usually be necessary to grind and screen the dried
product These methods for the recovery of hexavalent uranium from a
solution are thus laborious, result in pollution of the product and
often make succeeding processes for the manufacture of uranium metal
complicated.
In the method according to the present invention these drawbacks are
completely avoided Uranium is precipitated in the form of a compound
which is exceedingly easy to filter, and the process is easily carried
out, easily controlled and cheap The method consists in dissolving in
the aqueous solution containing hexavalent uranium one or more amides
to form a homogeneous solution and heating the solution to cause the
amide to hydrolyse whereby the p 1 H value of the solution increases
and ammonium uranate is precipitated The precipitate settles very
rapidly to a small end or ultimate volume and can very easily be
lPrice 3 s 6 d l separated from the solution by filtration or 45
centrifuging Preferably an amide of an easily volatile acid or an acid
with a p K value greater than 3 is used and of these preferably
carbamide or acetamide As a rule carbamide is preferred as it provides
a quicker and more 50 complete precipitation In order that hydrolysis
of the amide shall take place quickly the solution is heated,
preferably to 90 -1 '15 C.
Due to the fact that the amide is homogeneously distributed in 'the
entire solution no 55 great local excess of the neutralization agent
occurs when the amide is hydrolysed on heating It follows that a well
formed product of high volume weight and having less impurities on
account of enclosures and adsorptions is 60 obtained.
After drying the product easily falls to a powder of very uniform
grain size It is, therefore, well suited to be used without grinding
and screening In operations in the dry state, 65 for instance,
according to the fluidized bed principle The dried product is not
dusty to any material extent which minimizes the risk of toxic effects
and makes the product easy to handle 70 When carbamide is used ammonia
and carbon dioxide are obtained on hydrolysis It would be expected
that the carbon dioxide split off would form soluble complexes with
uranium and that the process would not give so favour 75 able a result
as it, surprisingly enough, has given.
On the above hydrolysis of carbamide the p H value of the solution
increases causing the uranium to precipitate Experiments carried 80
out have indicated that the ultimate p H value obtainable at a given
temperature depends on the percentage of ammonium salts in the
solution By controlling the percentage of ammonium salts in the
solution, it is therefore 85 possible within certain limits to adjust
the maximum or ultimate p H value This p H value can be so chosen that
the uranium will 111 'I1 1 be practically completely precipitated
while, on the other hand, hydroxides of, for instance, Cd, rare earth
metals, Hg, Be, Fe", Cr, Ni, Co, Zn, Pb, Mn, Mg, and Ca have not
started to separate It is thus possible to obtain a product free from
a multitude of undesired metal ions by using at the end phase of the
process a p H value within the range 4 5-7 and preferably 5-6.
EXAMPLE 1.
Three separate solutions of uranyl chloride, sulphate and nitrate
respectively, containing grams per litre of uranium were adjusted with
ammonium hydroxide to a p H value of 3 Then 1 gram carbamide per gram
uranium was dissolved in each clear solution and the mixture was
heated to 100-103 C with stirring Within 30 minutes uranium started to
separate out, and within 2 hours the precipitation was complete.
The precipitates settled very quickly to a small ultimate volume The
products were filtered off on a Bichner funnel and washed with warm
water at 60 C under vacuum.
For the sake of comparison solutions of the above composition were
precipitated with a % solution of ammonium hydroxide at 951000 C,
whereafter the precipitates were stirred for 1 hour before
sedimentation and filtration which was also carried out on a Bichner
funnel under the same vacuum The results are given in the following
table.
TABLE
Filtration, funnel Product dried The solution Precipitation diam 5 5
centimtr at room temp.
Filtration velocity at washing with warm Cake water Filtrate thick (
600 C) milliUraniumM iii end ness, litre/sq gram/ gram/ Uranium
Afillih end centi meter/ litre milligram/lit litres Anion p H metres
hour of U % U % NH 3 litre 200 Cl Hydro 6 5 0 8 360 6 73 0 1 4 1 14
lysis 200 504 of carb 6 0 1 0 650 52 64 6 3 5 1 36 amide 200 NO 3,, >
6 7 0 5 570 6 72 0 1 3 1 79 200 Cl 25 % 6 7 2 0 4 1 1 73 9 1 9 1 05
ammonia 200 504 1,, 5 6 1 5 4 8 80 64 6 3 7 1 05 200 NO 3 J,, 6 0 2 0
3 2 2 72 8 1 6 1 22 \ O 785,997 The filtration velocities refer to
washing with 600 C water of equal amounts of uranium on the filter It
will be readily seen that the products obtained by precipitation by
hydrolysis of carbamide gave filtering velocities of quite a different
order from those obtained by precipitation by addition of ammonium
hydroxide.
EXAMPLE 2.
A solution of uranyl nitrate containing 100 grams of uranium per litre
was adjusted with ammonium hydroxide to a p H value of 3 In the clear
solution 2 5 grams acetamide per gram uranium were dissolved, and the
solution was then heated to 100-103 C with stirring.
Within 30 minutes uranium began to precipitate After 5 hours a p H of
4 6 was attained.
The precipitative settled quickly to a small end volume The product
was filtered on a Biichner funnel The percentage of uranium in the
filtrate was 4 grams per litre The product was washed in the same
manner as in Example 1 The velocity of filtration on washing was 310
litres per square meter per hour.
A comparison with Example 1 indicates that the precipitation of
uranium proceeds quicker and more completely with carbamide than with
acetamide.
EXAMPLE 3.
Hereinbelow the results of some experiments are given showing what p H
values can be obtained at 100-103 C and with various percentages of
ammonium salts in the solution.
Salt NH 4 NMM (NH 4)"SO 4 gram/litre 300 end p H 6.3 5.9 5.5 5.8 5.4
It is seen that within given limits it is possible by variation of the
percentage of ammonium salts to obtain the desired end p H at the
precipitation of uranium by hydrolysis of carbamide.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* Last updated: 08.04.2015
* Worldwide Database
* 5.8.23.4; 93p
* GB785998 (A)
Description: GB785998 (A) ? 1957-11-06
Method for the preparation of di-halo-glycol diethers
Description of GB785998 (A)
Translate this text into Tooltip
[75][(1)__Select language]
Translate this text into
The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
PATENT SPECIFICATION
785,998 Date of Application and filing Complete Specification: Aug 26,
1955.
e% S ark No24620/55.
Application made in France on Sept 16, 1954, Co plete Specification
Published: Nov 6, 1957.
Index at acceptance:-Class 2 ( 3), CIE 4 K( 2: 6: 8: 9), C 1 G 2 B( 1:
2), CIG 5 (A: B), C 1 G 6 (A 2: A 3:
B 3).
International Classification:-CO 7 c, d.
COMPLETE SPECIFICATION
Method for the preparation of Di-Halo-Glycol Diethers We,
BOZEL-MALETRA SOCIBTE INDUSTRIELLE DE PRODUITS CHIMIQUES, a body
corporate organised under the laws of France, of 38, rue de Lisbonne,
Paris, France, do hereby declare the invention, for which we pray that
a patent may be granted to us, and the method by which it is to be
performed to be particularly described in and by the following
statement: -
The present invention relates to a method for the preparation of
dihalo-glycol diethers, as well as to the products obtained by this
method.
It is known that halo-methylated ethers, having the general formula
RO-CH 2 X, may be obtained by reacting formol with an alcohol R-OH in
the presence of a hydrogen halide HX, X being a halogen and R an alkyl
radical.
Said halogenated ethers are commonly used as intermediate products for
various organic syntheses, particularly for obtaining chloromethylated
derivatives according to the formula R 1-CH 2 C 1.
Such methods, however, have not made it possible heretofore to prepare
compounds according to the general formula R-O-CHX -CHX-O-R or XHC CHX
1 U 0 O R' An object of the present invention is to provide a method
for the preparation of dihalodiethers derived from ethane and having
the general formula ( 1) XHC-CHX l l 0 O R 1 univalent aliphatic
hydrocarbon radicals or together constitute a divalent aliphatic
hydrocarbon radical thus forming a ring Preferred compounds are those
in which R and R' are methyl or ethyl radicals or in which R and R'
together are a -CH 2-CH 2 radical.
The method according to the invention consists in causing an alcohol
or a glycol and a hydrohalic acid to act on glyoxal.
According to the invention, glyoxal is dissolved, in the form of a
concentrated aqueous solution or in powdered form, in, an excess of
alcohol or of glycol, the solution is cooled, the hydrohalic acid is
introduced therein, preferably in a gaseous condition, the
dihaloglycerol diether thus formed is separated either by
crystallisation from the mixture or by extraction by means of a
solvent.
The alcohols capable of being used for working the method are, for
example, methyl alcohol, ethyl alcohol and butyl alcohol As glycols,
ethylene-glycol may be more particularly mentioned.
Hydrochloric acid or hydrobromic acid may be used as hydrohalic acids
according to the final products desired.
For facilitating the dissolution of the glyoxal, a certain amount of
hydrohalic acid may be introduced in the solution as it is being
formed Iit is also possible to add the alcohol or glycol to the
solution containing glyoxal after the gaseous hydrohalic acid has been
introduced.
Finally methylene chloride, carbon tetrachloride, ethyl ether and the
like may be used as extraction solvent.
The dissolving of the dialdehyde may be facilitated by heating and/or
stirring the mixture.
The temperature of introduction of the hydrohalic acid should be
chosen sufficiently low so that the dihalo-glycol diethers formed do
not react with the alcohol in excess; temperatures below 25 C are
preferably used.
The method when carried out under the above conditions provides a
number of new in which X is a halogen and R and R' are compounds which
are clearly characterised both chemically and physically; they are
crystalline solids or liquids insoluble in water but easily soluble in
organic solvents In the presence of water, they undergo saponification
to give the starting materials In the absence of water they are
completely stable and may be purified by distillation.
These dihalo-glycol diethers are extremely valuable in organic
synthesis due to the high reactivity of their halogen atoms; they
condense in particular with all alcoholic or phenolic -OH groups thus
making possible preparation of numerous new diacetals; they also react
with the substances possessing an H atom, particularly with carboxylic
hydrogen, or an active metal atom.
On the other hand, the alkoxy -R-Ogroup of these dihalo-glycol
diethers can also condense with substances of the aromatic series;
this provides an easy and economical synthesis for substances of the
diphenylethane series according to the reaction.
2 Ar H + R-O-CHX-CHX-O-R Ar-CHX-CHX-Ar + 2 R-OH in which Ar is an aryl
radical.
When zinc reacts with the dilialides thus prepared, derivatives of
stilbene are obtained.
By ithe action of alkaline reagents, it is possible to obtain
halogenostilbenes Ar-CH= CX-Ar or tolanes Ar-C= Ar, or other like
derivatives.
Finally, the invention provides an important advance in the synthesis
of some products which were heretofore accessible only by means of
difficult methods Such is the case, for example, of the preparation of
2,3-dichlorodioxane which could only be obtained heretofore by
chlorination of dioxane but which can now be prepared according to the
present invention, from glyoxal, ethylene glycol and hydrochloric
acid.
EXAMPLE 1
220 parts in weight of 78 % powdered glyoxal are mixed with 425 parts
in weight of methyl alcohol, a small amount (about 10 parts) of
gaseous hydrochloric acid is introduced into the mixture and the
mixture is heated with stirring at 40-50 C until the glyoxal is
completely dissolved.
The mixture is then cooled ito between 0 and 15 WG, and 365 parts of
dry, gaseous hydrochloric acid are introduced over a course of 4
hours.
An abundant mass of crystals are formed which are dried and rinsed
with a small amount of cold methanol followed by a small amount of
cold ether 380 parts of pure 1: 2dimethoxy-l 2-dichloroethane are
obtained.
Melting point 70 50 C Chlorine content 44 2 i% (calculated content
44.6 %) Yield 80/% EXAMPLE 2
A mixture of 220 parts by weight of powdered glyoxal ( 78 %) and 425
parts of methyl alcohol are treated as in Example 1, the hydrochloric
acid being replaced by 810 parts of gaseous hydrobromic acid.
1: 2-dimethoxy-1: 2-dibromoethane is obtained and then dried and
immediately recrystallized from carbon tetrachloride The final nroduct
has a melting point at 720 C and a bromine content of 60 %'
(calculated content 64.5 %).
EXAMPLE 3
1330 parts of methylene chloride are mixed with a solution of 50 C%
glyoxal comprising 435 -parts in weight of glyoxal ( 100 %) dissolved
in 435 parts of water and the mixture saturated with gaseous
hydrochloric acid, the temperature being maintained at about O GC.
690 parts of ethyl alcohol are then slowly introduced, while
continuing the bubbling of hydrochloric acid through the mixture and
while maintaining the temperature in the vicinity of 00 C.
After saturation, the lower layer, consisting in a mixture of 1:
2-diethoxy-1:2 dichloroethane and methylene chloride, is separated
off, dried over calcium chloride and a double distillation carried out
under reduced pressure.
1100 parts of diethoxydichloroethane are thus obtained distilling
under 40 mm Hg at WC, having a specific gravity of 1 135 at C, a
melting point at 17 WC and a chlorine content of 37 1 % (calculated
content 38 %o).
EXAMPLE 4
Into a well-stirred mixture of 500 parts by weight of a 60 % glyoxal
aqueous solution, 284 100 parts of ethylene-glycol and 800 parts of
carbon tetrachloride, is introduced gaseous hydrochloric acid under a
slight pressure until the mixture is saturated, the temperature being
maintained below 50 C 105 After standing for a few hours at room
temperature, the lower layer, consisting of carbon tetrachloride and
2: 3-dichlorodioxane, is decanted; the upper layer is then again
saturated with hydrochloric acid in the pre 110 sence of a further
amount of 800 parts of carbon tetrachloride These operations are
repeated three times.
The four mixtures of carbon tetrachloride and 2: 3-dichlorodioxane
thus obtained are 115 bulked together and re-distilled under reduced
pressure.
193 5 parts of pure 2: 3-dichlorodioxane are finally obtained,
distilling under 23 mm Hg between 89 and 95 WC 120 785,998 solution of
glyoxal, in which alcohol or glycol is then introduced.
8 A method according to any one of the preceding claims, in which
glyoxal, ethyleneglycol and hydrochloric acid are used as starting
materials for obtaining 2: 3-dichlorodioxane.
9 Dihialo-glycol diethers derived from ethane of the general formula:
The reaction gives practically rno secondary products.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* Last updated: 08.04.2015
* Worldwide Database
* 5.8.23.4; 93p