quiz 2 bisphenol a belaro

7/23/2019 Quiz 2 Bisphenol a Belaro

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BISPHENOL-A

Researched and Compiled by: CHALMER M. BELARO

1. Chemical and Physical Description

1.1. Physical Properties

Bisphenol A, also known as

2,2-Bis(4-hydroxyphenyl) propane and

4,4′ -Isopropylidenediphenol, shown in

Fig. 1, is a white crystalline solid,

appearing like small white to light

brown flakes or powder, with mild

phenolic odor but is not volatile, which

sinks in water. Its specific gravity is

given as 1.195 at 25/25℃. There is no

data regarding its vapor density. For

the boiling point, records show discordant temperature ranges and imprecise pressures;

181 to 195℃ at 4 mm Hg, 195 to 200℃ at 6 mm Hg, 230℃ at 7.6 mm Hg. Other sources

suggest 100-200℃

range of boiling point. BPA is volatilized only in traces by steam at 1

atm. Pure BPA has a melting point of 157℃. Other physical properties of BPA are

presented in Table 1.

Table 1. Other physical properties of BPA

Bulk density 0.492 g/cm3

Heat of vaporization at 1 atm 404 J/g

Flash point 227℃

Solubility at water at 83℃ 0.344 wt %

Figure 1. Bisphenol A (PC Grade)



1.2. Chemical Properties

The chemical properties of Bisphenols are

determined by Phenolic OH groups, the aromatic

rings and the alkyl bridge. They therefore undergo

the same reactions as the corresponding

substituted monophenols. They are also suitable

as building block for higher molecular mass linear

polyesters and polyethers because of their

bifunctionality. Bisphenols which are alkyled ortho

to the OH group readily trap radicals and are

therefore suitable as stabilizers. Under

hydrogenation condition, BPA is cleaved to give

4—isopropylphenol, alkali catalyzed cleavage

gives 4-isopropylphenol in good yields. Both

compounds are good to obtain by other methods.

The alkali catalyzed cleavage of various

Bisphenols has been investigated. The cleavage

can also be catalyzed by acid to form indans and spirobisindans. The purely thermal

cleavage is generally less forward. Chemical structure of the substance is shown in Fig.2.

2. Production

Bisphenol A is a

component of

polycarbonate plastics

and epoxy resins and is

one of the highest-

volume chemicals

produced globally.

Figure 2. a. 2D structure of BPA (Upper)

b. 3D conformer of BPA (lower)



Process technologies available for the manufacture of BPA on commercial level

are:

Condensation of phenol with acetone using acid as catalyst;

Condensation of phenol with acetone using ion exchange resin catalyst.

Acid c atalyzed condensation of phenol and acetone is one of the commercial

route commonly used for BPA production being the oldest process for its production. In

this process phenol and acetone in 3:1 molar ratio are reacted in four glass lined stirred

reactor at 50℃ and 1 atm pressure using anhydrous hydrochloride catalyst and methyl

mercaptan as promoter. The residence time is around 3hr in this process in all four

reactors. The reaction is exothermic, cooling water is passing through the reactor jacket

for cooling. Around 99% of the acetone is converted into BPA. Phenol is used in the excess

to ensure predominance of the forward reaction. The most important controlling parameter

is temperature. Higher temperature causes the isomerism of BPA. With further increase

in temperature, viscosity of reaction mixture keeps on increasing. Hydrochloric acid is

stripped off from the crude product of the reactor which is recovered and recycled. The

product is further purified in the next distillation column where water is separated. During

distillation, some stabilizers are added to prevent isomerism of bisphenol to o- and p-

isomers. The reaction product is then distilled under a reduced pressure in phenol-

bisphenol a column. Further the purification of BPA for removal of o- and p- isomers takes

place. The product is further purified by crystallization.

Table 2 presents the raw material requirement per 1000 kg of BPA required in its

manufacturing.

Table 2. Raw Material Requirement for Acid-catalyzed

Condensation of Phenol and Acetone

The typical BPA product obtained is 99.9% pure while the typical feasible plant

capacity is 7000 MTPA (metric tons per area) to 30000MTPA.

Process selectivity 95%

Phenol 860 kg

Acetone 275 kg

Steam (Energy) requirement 12.5 GJ/ton



Ion exchange resin catalyzed condensation of p henol with acetone is the new

improved process for the production of Bisphenol-A. Ion exchange resin is today’s

preferred catalyst system for BPA manufacturer. It replaces older acid based technologies

by doing away with acid based environment. All of the problems associated with handling

acids, including corrosion and disposal of acid waste are eliminated. It’s a fully continuous

process that incorporates catalytic stripping, a novel reactor technology for the

condensation of phenol and acetone. This advanced technology maximizes yield and

conversion using an environmentally preferred ion exchange resin catalyst. The new

reaction system promotes the BPA condensation reaction under highly favorable reaction

condition while simultaneously removing the water of reaction. The catalytic stripping

reactor provides a very high effective phenol to acetone ratio that, together with an

improved high activity and high selectivity catalyst, results in complete conversion of

acetone and max phenol conversion, with low by product formation. Much higher

conversion and better selectivity are achieved than with other ion exchange catalyst

system. This reduces recycles and utility consumption thereby reducing operating and

capital costs. High phenol conversion permits a simple 1 stage crystallization system.

Raw material consumption per 1000 kg of BPA obtained in this process is

presented in Table 3.

Table 3. Raw Material Consumption for Ion Exchange Resin Catalyzed

Condensation of Phenol and Acetone

The typical BPA product obtained is 99.93%-99.98% pure while the typical

feasible plant capacity is 25000 MTPA to 100000MTPA.

More detailed comparison of the two processes in manufacturing BPA is presentedin Table 4.

Process selectivity 98.5%

Phenol 835 kg

Acetone 265 kg

Steam (Energy) requirement 6 GJ/ton



Table 4. Comparison of Different Processes Available for Production of Bisphenol A

Due to the above-mentioned points of advantages of condensation of phenol and

acetone with ion exchange resin catalyst, it is apparently more economical, less polluting,

and most advanced technique for the production of BPA, thus, will be more explored in

this paper.

Parameter of DifferentiationAcid Catalyzed

Process

Ion Exchange ResinCatalyzed Process

BPA purity (%) 99.90 99.93-99.98

2-4 isomers ppm (max) Not normalized 150

Color (APHA) max 5 5

Phenol consumption (kg/t) max 860 835

Acetone consumption (kg/t) max 275 265

Steam (Energy) Requirement(GJ/t)

12.5 6

Catalyst life time (years) 10 Up to 15

Corrosion problem Present at greaterextent

Not such problemsseen yet

Acid Handling Required Not required

Disposal of waste A problem No such problems

Conversion rate Low High

Recycle Rate High Low

Capital Investment High Low

Utility Consumption High Low

Maintenance Cost High Low

Stage Multi stage portfolio Single stage portfolio

Catalyst HCl High activity ionexchange resin catalyst



2.1. Chemical reactions involved

The basic reaction of the acid-catalyzed condensation of acetone with 2 moles of

phenol is:

The heat of reaction, for reactants and products in their natural physical state at

25℃, is calculated from heats of formation as +18.4 kcal/mol. Severe conditions are not

required; a 1:2 molar ratio mixture of acetone and phenol, in the presence of concentration

hydrochloric acid or sulfuric acid at 70% at room temperature deposits a mass of crudeBPA crystals. The reaction conditions predominantly favor the formation of the product,

however, an excess of 1 mol of phenol is maintained in the production of BPA to ensure

this condition.

The reaction proceeds with an electrophilic attack of the proton from the acidic

catalyst on the molecule of acetone. This first step of the mechanism is very similar to the



one in the production of phenolphthalein and DDT and in the alkylation of phenol with

olefins shown in the following reactions.

2.2. Unit operations / Unit processes involved

The main unit operations involved in production of BPA includes ion-exchange,distillation, heat exchange, crystallization, stripping, and flaking.

A process catalyzed by a sulfonated cation exchange resin modified with 2-

mercaptoethanol is presented in Fig. 3 in Section 2.3. A mixture consisting of 83.4 %

phenol, 5.1% acetone, 0.1% water, 3.4% recycled BPA, and 8% recycled by-products are

preheated and fed to the reactor. The reactor is operated at 75℃ and pressure is kept

around 4.4. The residence time is set in one hour. The process runs to a 50% conversion

of acetone. The concentrator is operated at 200 mm Hg. The overhead at the concentrator

is a mixture of acetone, water and phenol at 18-20%. The bottom stream consists of

phenol, BPA, and by-products. The overhead passes through a series of distillation

columns with the first operating at 1700℃ and pressure of 560 torr will help in removing

water and unreacted acetone from the reactor effluent. Acetone and lights are sent to

second distillation column operating at 950℃ and then acetone is sent to the lights

absorber to produce a recycle acetone stream while water is sent for the waste water

treatment via recovery column. The bottoms of the crude column having the temperature

of 700℃ is sent to the crystallization feed pre-concentrator after it is passed from a heat

exchanger where inside temperature is 51℃ and it is cooled to 54℃, which distills phenol

and concentrates BPA to a level suitable for crystallization. BPA is separated from

byproducts in a proprietary solvent crystallization and recovery system where it is cooled

from 54℃ to 41℃ to produce the adduct of p-p BPA and phenol. Mother liquor from the

purification system is distilled in the solvent recovery column to recover dissolved solvent

which comes in this system through pump. After crystallization, the mixture is separated

in a centrifuge, washed with phenol, and freed of phenol by melting at 130℃, then

stripping in a column at 200℃ and 1 mm Hg. The solvent free mother liquor stream is

recycled to the recovery system. A purge from the mother liquor is sent to the purge

recovery system along with the recovered process water to recover phenol. The recovered

purified adduct is processed and fed at a temperature of 410℃ and pressure is kept

around 25 torr in a BPA finishing system to remove phenol from product, and the resulting



molten BPA of temperature 1750℃ is solidified in the flaker followed by a pump to produce

product prills which comes out at a temperature of 900℃ and is suitable for the BPA

market.



2.3. Process Flow Diagram

Figure 3. Ion Exchange Resin Catalyzed Process Flow Diagram for the Production of Bisphenol-A



The following table presents the amounts of phenol, acetone, BPA, and water in

the streams of the whole process.

Table 5. Streamwise Product Distribution

Stream No.PHENOL

(kg/hr)

ACETONE

(kg/hr)

BPA

(kg/hr)

WATER

(kg/hr)

1 - 168.78 - -

2 693.13 5.22 - -

3 146.05 5.22 663.48 52.38

4 - 5.22 - 52.38

5 146.05 - 663.48 -

6 - 5.33 - -

7 3.723 - - 52.38

8 138.75 - - -

9 7.30 - 663.48 -

10 - - 33.174 -

11 2.482 - - -

12 1.095 - 663.48 -

13 3.723 - 33.174 -

14 1.095 - - -

15 - - 663.48 -

16 - - 662.81 0.67

17 - - - 52.38

18 3.723 - - -

19 - - - 52.38

20 693.13 5.22 - -

21 547.08 - - -



2.4. Equiment

Operating conditions of the equipment in the process were explained along with

the operations in Section 2.2.

One main equipment used in the process is the reactor. The kind of reactor variesdepending on the design preference of the manufacturer. Fig 4 is the schematic design

of the fluidized bed by Instytut Ciezkiej Syntezy Organicznej "Blachownia".

Other equipment include distillation columns, crystallizer feed system, solvent

crystallization and recovery system, BPA finishing system, flaker, light absorber, and

recovery column.

Figure 4. Fluidized Bed Reactor for Production of Bisphenol-A



3. Applications and Use

Application Overview:



Production of Polycarbonate:



4. References

Agrawal, R., & Suman, A. (2012). Production of Bisphenol A. District Guna: Department of Chemical

Engineering, Jaypee University of Engineering and Technology. Association of Plastics Manufacturers. (2007). Applications of Bisphenol A. PlasticsEurope:

Polycarbonate/BPA Group.

Neagu, L. (1998). Synthesis of Bisphenol A with Heterogeneous Catalysts. Kingston, Ontario: Department

of Chemical Engineering, Queen's University.

O'Young, D., Hsieh, S., & Kelkar, V. (2007). United States of America Patent No. US 7,163,582 B2.

Sigma-Aldrich Co. LLC. (2012). Safety Data Sheet: Bisphenol A.

The Dow Chemical Company. (2012). Product Safety Assessment: Bisphenol A.

quiz 2 bisphenol a belaro

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