chain transfer agent
TRANSCRIPT
Chain Transfer Agents
Chain Transfer Agents
Technical brochure
2 Chain Transfer Agents
Thiochemicals and Chain Transfer Agents
� Main CTA:� n-octyl mercaptan (NOM)� n-dodecyl mercaptan (NDM)� Tertiary-dodecyl mercaptan (TDM)
� Other Light & Heavy Mercaptans� Methyl mercaptan (MM)� Ethyl mercaptan (EM)� Tertio-butyl mercaptan (TBM)� Benzyl mercaptan (BZM)� Tertio-nonyl mercaptan (TNM)
SHCH2R
SHR1
R3
R2
R1 CH R2
SH
Primary mercaptan
Secondary mercaptan
Tertiary mercaptan
3 Chain Transfer Agents
� Water soluble CTA:� Thioglycolic acid TGA
� Functional CTA:� Iso-octyl thioglycolate IOTG� 2-ethylhexyl thioglycolate EHTG
� Dithio coumpounds:� 1,8 Dimercapto 3,5 dioxaoctane DMDO
HS-CH2-CH2-O-CH2-CH2-O-CH2-CH2-SH
H S C H 2 CO
O R
TGA :R = H
IOTG :R = iso-C8H17
EHTG :R = CH2-CH(C2H5)-nC4H9
Other mercaptans
Thioglycolic acid and derivatives are odorless in comparison with the other mercaptans
4 Chain Transfer Agents
Europe2 R&D centers:� GRL (Lacq, F)� CRRA (Lyon, F)3 Plants:� Lacq (F),� Mourenx (F)� Rotterdam (Nl)
North America1 R&D center:� KoP (Pa)4 Plants:)� Houston (Tx)� Beaumont (Tx)� Mobile (Al)
Thiochemicals A Global Business
Asia1 R&D center:� KTC (Kyoto, J)4 Logistic Hubs:� Japan,� Singapore� Taiwan� China
5 Chain Transfer Agents
Mercaptan (=Thiols) Processes
� NOM, NDM: photochemical process
� TDM: catalytic process
RCH2
H2S
hγR
SH
H2S
catalyst
S H
6 Chain Transfer Agents
Specifications
≤15≤20≤15Color APHA
ClearNo turbudity or suspended matter
No turbudity or suspended matterAppearance
PotentiometryPotentiometryPotentiometry
≥98.5≥98.5≥98.5Purity (wt-%)
+ Method
≥15.6≥ 15.5≥ 21.6Mercaptan Sulfur (wt-%)+ Method
Spectrophotometer
Calculated from Mercaptan Sulfur
TDM
SpectrophotometerSpectrophotometer
ChromatographyChromatography
NDMNOMProduct
7 Chain Transfer Agents
Insoluble in water (20°C)
Hydrocarbons
TDM TGANOMNDM
Solubility
Completely soluble (20°C)
Alcohols
Ethers
Practically Insoluble in water (20°C)4mg/mL
Hydrocarbons
Alcohols
Ethyl ether
Insoluble in water (20°C)<1mg/mL
Hydrocarbons
Alcohols (slightly)
Solubility parameters
8 Chain Transfer Agents
OdorDetection limits of some thio compounds
Detection limit (ppb vol)
0
0.25
0.5
0.75
1
1.25
Methyl
merca
ptan
Ethyl m
erca
ptan
n-pr
opyl
merca
ptan
i-pro
pyl m
erca
ptan
n-bu
tyl m
erca
ptan
i-buty
l mer
capta
n
t-buty
l mer
capta
n
0
5
10
15
20
25
Hydro
gen s
ulfide
Dimeth
yl su
lfide
Diethy
l sulf
ide
Di n-p
ropy
l sulf
ide
Di i-pr
opyl
sulfid
e
Dimeth
yl dis
ulfide
Diethy
l disu
lfide
Ethyl m
ethyl
disulf
ide
Dimeth
yl tris
ulfide
Diethy
l trisu
lfide
Tetrah
ydro
thiop
hene
Detection limit (ppb vol)
These products smell at ppb concentrations because human nose is very sensitive to thiols.F.V. Willby, 35 persons panel
Ex: MeSHHuman Olfactory Threshold = 1 ppb = 0.001 ppmThreshold Limit Value - Short Term Exposure Limit = 0.5ppm
9 Chain Transfer Agents
TDM(butadiene based copolymers)
Rubber (SBR/NBR)Latex (SB latex/XSBR)Plastics (ABS/PS)Resins (Toner/MBR)…
Main application domains of Thiols
Homogeneous BulkSolutionGas phase
HeterogeneousSuspensionEmulsion
NDMRubber (neoprene)Plastics (ABS/PMMA)
NOMPlastics (ABS/PMMA)
Reaction Medium
Continuous
Semi-continuous
Batch
Process Unit
Each process/recipe is optimized with a specific chain transfer agent.
Chain Transfer Agents
Chain Transfer Agents
Mechanism & Performances
11 Chain Transfer Agents
Free Radical Polymerization Mechanism
MW
12 Chain Transfer Agents
FRP with Chain Transfer Agent
Transfer to thiol (=mercaptan)
MW
13 Chain Transfer Agents
Main CTA characteristics
� The efficiency of a chain transfer agent (CTA) is characterized by a chain constant: Ctr
� Ctr is directly impacted by the monomer (or mixture of monomers)
� Propagation rate and MW distribution are also impacted by re-initiation step
Transfer rate coefficient (ktr)
Propagation rate coefficient (kp)Ctr=
����Degradative
Transferkp<<ktr and ki<kp4
��Retardationkp>>ktr and ki<kp3
��NoneTelomerizationkp<<ktr and ki≈kp2
�NoneNormal Transferkp>>ktr and ki≈kp1
MWRpEffectKineticsCase
14 Chain Transfer Agents
SBL (75/25) polymerization
0
0.25
0.5
0.75
1
0 0.25 0.5 0.75 1Monomer Conv.
RS
H C
onsu
mpt
ion
t-C8t-C12t-C14t-C16
SBL (75/25) polymerization
0
0.25
0.5
0.75
1
0 0.25 0.5 0.75 1Monomer Conv.
RS
H C
onsu
mpt
ion
n-C8n-C12n-C14n-C16
SBL (75/25) polymerization
0
0.25
0.5
0.75
1
0 0.25 0.5 0.75 1Monomer Conv.
RS
H C
onsu
mpt
ion
NDM
TDM
RSH characteristics
� Primary thiols are much reactive than secondary and tertiary
� The shorter the chain, the faster the transfer
Chain Transfer Agents
New Chain Transfer Agentsfor
RAFT polymerization
Mechanism & Performances
16 Chain Transfer Agents
Controlled Radical Polymerization (CRP) versus FRP
MWMW
* RAFT: Reversible Addition Fragmentation Transfer
17 Chain Transfer Agents
Random Copolymerization
MWMW
18 Chain Transfer Agents
MW
+
Block copolymerization
MW
19 Chain Transfer Agents
Product� Formula
� RN CAS : 26504-29-0
� Purity > 95 %� Physical state: solid (mp ≈ 27-30°C)� Degradation temperature > 250°C
� Almost odorless product� Irritant
� Available for sampling or purchase� Already synthesized at pilot scale
DiBenzylTriThioCarbonate (DBTTC) for RAFT Polymerization
S
S
S
Registration
� ELINCS registration(done for V<1T)
� And outside E.U. zone(on request)
� TSCA registration (on going)
Legal part
� Arkema holds IP patent rights (license + sub-license) for the use of RAFT agents in some specific polymerization processes and their applications
� Product available under secrecy agreement
Under development at Arkema
20 Chain Transfer Agents
Thiochemical Innovators
Our technological expertise
� Sulfur chemistry synthesis starting from S, H2S,NaSH or CS2
� Application knowledge in refining, steam-cracking, polymerization, gas odorization, metal plating, mining and lubrication
Our lab tools
� Analytical means especially developed for Thiochemicals and heavy general analytical capabilities
� Olfactometric laboratory to help your address issues linked to odors in your application
� Application testing equipment: flotation cell, polymerization equipment, plating cells,tribological testing tools, polymer characterization, steam cracking andhydrotreatment lab pilots…
Our industrial development equipment
� Arkema operates several pilot and multi-purpose plants managed under ISO9001 and ISO14001 standards, with a total reactor capacity exceeding 75m3, either glass-lined or stainless steel
� These facilities, staffed with senior scientist, engineers and project managers, can apply a large range of reactions and process capabilities
� They allow Arkema a fast scale-up of new molecules from the lab to industrial production
Address us your request for new CTA