copy of ncl 2006 pet. chem

8/4/2019 Copy of NCL 2006 Pet. Chem.

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Catalysis inPetrochemical production

Lecture 3


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CONTENTS

1. Petroleum feedstocks2. Petrochemicals from different hydrocarbons

3. Alkylation reactions4. Shape-selectivity5. Isomerization reactions6. Disproportionation7. Catalytic reforming8. Selective oxidation reactions9. Green polycarbonate synthesis


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INTRODUCTION

Feed stocks for petrochemicals are gas

and light to middle petroleum liquids Nearly all the petrochemicals are produced

over catalysts Both homogeneous and heterogeneous

catalysts are involved


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Chemicals from methane


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C2H6 - C3H8C4H10 -naphtha C2H4; C3H6; C4H8(steam cracking) + Pyrolysis gasoline

Ethane, propane, butane, isobutane, naphtha and keroseneare also feed stocks for many chemicals

Pyrolysis gasoline BTX

Naphtha BTX (Catalytic reforming)

Kerosene n-paraffins n-olefins LAB(separation and alkylation)


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Uses of benzene

Nitrobenzene

Cyclohexane

CumeneEthylbenzene

AROMATIC COMPOUNDS


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Chemicals from toluene

Xylenes are also important petrochemical products / feed stocks


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MeOH acetic acid Vinyl acetate

Ethylene ethylene oxide ethylene glycolEthylene acetic acidEthylene ethyl alcoholEthylene vinyl chloride

Propylene propylene oxide Propylene glycolPropylene

acrylic acid ; acrylonitrilePropylene allyl chloride epichlorohydrin propylene oxide

Petrochemicals some more examples

Butenes Maleic anhydride

OLEFINS ARENOTPRESENT INPETROLEUM


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Benzene Maleic anhydrideBenzene Chlorination; nitration etc.p-Xylene Terephthalic acido-Xylene Phthalic acid

Many polymers are derived from the above petrochemicals Hundreds of other chemicals are derived from olefins,

BTX, phenol, acetic acid, methanol etc.

Cyclohexane cyclohexanol + cyclohexanoneCyclohexanone CyclohexanoneoximeCaprolactam Nylon-6Cyclohexanol adipic acid Nylon-6,6

Cumene Phenol + acetoneEthylbenzene styrene


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Major reactions in

petrochemical production

1. Alkylation

2. Isomerization3. Disproportionation4. Selective oxidation

5. Dehydrogenation


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1. Replace mineral acids by solid acids2. Green selective oxidation reactions

a) Adipic acidb) Propylene oxidec) Oxidation of alkanesd) Phenole) Alkane oxidations with air

3. Caprolactam production

Examples:

Petrochemical production has been a major polluting industry

Recently, there is an increasing effort to make petrochemical

production greener

Greening of petrochemical production


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Alkylation of Aromatics


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Some important industrial alkylation reactions over acidic zeolites

Reactants Product Catalyst Process licensors

Benzene + ethylene /EtOH EB ZSM-5 Mobil-Badger /NCLetc

Benzene + propylene Cumene H-Y; H-M; H- DOW, UOP etcToluene + methanol P-Xylene Modified ZSM-5 MobilBenzene + C11C13 olefins LAB Solid acid/ RE-Y UOP / NCL

EB + EtOH P-DEB Modified ZSM-5 NCL / IPCL

Naphthalene + propylene 2,6-DIPN H-mordenite Chiyoda

Naphthalene + methanol 2,6-DMN Zeolite Rtgerswerke

Biphenyl + propylene 4,4-DIPB H-mordenite DOW


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Industrial alkylation Processes


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Alkylation is the introduction of an alkyl group into a moleculeIt may involve a new C-C, O-C, N-C bond formationAlkylation is catalyzed by acidic or basic catalysts

INTRODUCTION

Acid catalysts are used mainly in aromatics alkylation at ring-CBasic catalysts are used in alkylation at side-chain-C

CH3

+ MeOH

CH3

CH2CH3

CH3

Acid Catalyst

Basic Catalyst

(p-Xylene)

(Ethylbenzene)


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Example of an alkylation mechanisms

Because the Sec-C+ is more stable, mostly cumene is (> 99.9 %)

is produced and not n-propyl benzene (requires thePrim-C+)

Mechanism 1;Sec-C+ is formed

Cumene production:


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What are ZEOLITES ?

- Aluminosilicates- Crystalline- Framework of

AlO4 and SiO4 Td-units

- Possess ordered pore systems

- Acidity arises from Al-ions

The most important solid acid catalysts in industrial use are

ZEOLITES


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Sodalite(SOD)Pores ~3

Zeolite - A(LTA)

pores ~ 4

Zeolite - X, Y(FAU)pores ~ 7.4A large cage (~ 12)

formed in A and X,Y

Example ofbuilding zeolite

structures

4 & 6 memberedrings

[SiO4 ]4-[AlO4]5-

-cagesLTA FAU


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ETHYL BENZENE

kg

Data as of year 2000

NCL

Main use of EB: Manufacture of styrene


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ReactorsTemp. (C)

WHSV (h-1

)

Pressure

Benzene / alc. (mole)

Alcohol sel. (%)

EB + DEB (%)

EB (%)

Cycle length (days)

No. of cycles

3 beds in series380 420 C

5 10 (6)

1 - 4

4 15 (5)

98

95

85

45

>25

Albene process

(NCL)15,000 tpa plant was incommercial operation

for some years

+ + H2O

CH2 CH3

CH2CH3 OH

Mobil-Badger process is based on ethylene and uses ZSM-5;Other licensors are UOP, CDTECH etc; use other zeolites

CDTECH process uses reactive distillation

Mobil-Badger process

Catalyst is Encilite

pentasil (ZSM-5) type


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Mobil-Badger process

Uses ethylene as the alkylating agent

T = 370 - 420C; P = 7

27 bars;


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[Degnan et al. Appl. Catal. A 221 (2001) 283]

Kg

> 40 SPA units have been licensed (UOP

CUMENE

Main use of cumene: in the production of phenol


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Comparison of NCL(H-beta) and SPA

catalysts

CATALYST N.C.L. S.P.A.

Mole Ratio (benz./C3) 6.0 8.0

Temperature (C) 150 210

Pressure (bar) 30 30

WHSV (h-1

) 3.5 2.5

Products (wt. %)

Aliphatics 0.003 0.67

Toluene + Ethylbenzene 0.01 0.01

Cumene 22.03 17.18

Di-isopropylbenzene 1.70 1.11

Conversion of propylene 99.99 99.90

CUMENE

NCL processes foralkylation andtransalkylation are

available

Benzene + propylene CumeneProcess licensors: UOP, CDTECH, Enichem, Mobil-Badger, DOW

Zeolite processes involve atransalkylation (with benzene)step to convert >10 %di i-pr-Bz into cumene

Yield of cumene in zeoliteprocesses is more astransalkylation is not possiblewith SPA catalysts


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CDcumene process (CDTECH)

Reaction is done in catalytic distillation reactorThe catalyst is held in distillation traysA transalkylation reactor converts the di-iprBz.

Features


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Comparison of two different zeolites in the alkylation of benzene by propene_____________________________________________________________________Parameters Catalyst Catalyst

MCM-22 MCM-56_____________________________________________________________________Temperature, oC 112 113Propene flow, WHSV, h-1 1.3 10.0Propene conversion, % 98.0 95.4

Selectivity, %- Cumene 84.35 84.98- Diisopropyl benzene 11.30 13.20- Triisopropyl benzene 2.06 1.28- C3 Oligomers 1.8 0.52

- n-Propyl benzene, ppm 70 90_____________________________________________________________________

(J.C. Chang et al., US Patent. 5,453,554 (1995))


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CH3

+

i-Pr

i-Pr

i-PrCatalyst

Diisopropyl benzene transalkylation


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Influence of zeolite-type on m/p ratio of DIPrB


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LINEAR ALKYL BENZENE


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UOP

Evolution ofLAB processes;

BecomingGREENER

Benefits in product

quality -use of solid acid

Green

Catalyst

AlCl3AlCl3HFSolid acid


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Production of LABAlkylation of benzene with C11 C13 olefins


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Heavyalkylates

H2 rich off gas

Distillation

N-paraffin recycle

ParaffinRecovery

BenzeneRecovery

Alkylation

Solid-acidCATALYST

Make up H2

PACOL

DehydrogenationPt/Al

2O

3

Selective

HydrogenationDEFINE

Fresh n-paraffin

H2 recycle Fresh benzene

B

enzenerecycle

LAB

Linear alkyl benzene (LAB) using a solid-acid catalyst

Detal process for Linear Alkyl Benzene production


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Feed: mixed olefins (C10 - C13)Temp. (C) = 130 - 180Press. = 5 - 10 barsWHSV (h-1) = 2 - 3- Conversion > 99.99%; product BI < 50 ppm- The catalyst life was >50 days in a single cycle- Catalyst could be regenerated many times

Operated in RIL in a semi-commercial scale (~ 800 tpa)

NCL alkylation process for LAB usingsolid acid catalyst


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Shape-selective alkylation reactions

1. p-Ethyl toluene

2. P-Diethyl benzene

3. 2,6-Dialkyl naphthalene

4. 4,4-Dialkyl biphenyl

P d t h l ti it f l i i klk l i


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Product shape selectivitymost useful in aromatic aklkylation

Alkylation of toluene with ethylene (Mobil)

Catalyst:(%) AlCl3HCl ZSM-5 ModifiedZSM-5

Toluene conv. 51.7 25.6 13.8

Ethyltoluene 35.9 22.0 12.3

Other aromatics 15.8 3.0 1.5Ethyltoluene:

Para 34.0 26.8 96.7

Meta 55.1 60.6 3.3

Ortho 10.9 12.6 0

CH CH


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P-Diethylbenzene

Catalyst

Temp. ()

EB / Alc. (mole)

WHSV (h-1

)

Pressure (bar)

Conversion per

pass (%)p-DEB sel. (%)

Pore-size

engineered zeolite

340 410

4 10

1 4

2 5

10 16>97Product shape-selectivity in a zeolite

NCL Process operated in a commercial scale (500 tpa)

+ CH2CH3 OHZeolite

CH2 CH3

CH2 CH3

CH2 CH3

Alk l ti f hth l


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Alkylation of naphthalene

1-IPN

2-IPN

1,4-DIPN 1,5-DIPN 1,8-DIPN

1,2-DIPN 1,3-DIPN 1,6-DIPN 1,7-DIPN

2,3-DIPN 2,6-DIPN 2,7-DIPN

2,6-dicarboxy naphthalene is a valuable monomer for the synthesisof PEN polymers

This can be produced from the oxidation of alkyl naphthalenesDirect alkyklation yields ten isomers that are difficult to separate

Indirect routes have, therefore, been adopted for their synthesis


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CH3

CH3

+ CH2=CH-CH=CH

2

Alkali Metal Catalyst

NaK

Alkenylation

CH3

CH2-CH2-CH=CH-CH3

OPT

CH3

CH3

Zeolite Catalyst

Cyclisation

1,5-DMT

Pt / Al2O3

Dehydrogenation

1,5-DMN

Zeolite Beta

Isomerization2,6-DMN

BP-Amoco route for synthesis of 2,6-dimethylnaphthalene

[Lillwitz, Appl. Catal. A 231 (2001) 337]


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CH3

+ C5H

10

Zeolite Y

Alkylation

CH3

C5H

11

TPs

CH3

C5H

11

Pt / Re / Al2O3 / Cl

Reforming DMNs

Pd / Beta

Hydroisomerization

DMTs

Pd / Beta

Hydroisomerization

2,6-DMT

Dehydrogenation

Pt / Na-ZSM-5

2,6-DMN

Chevron-Texaco route for synthesis of 2,6-dimethylnaphthalene

[Lillwitz, Appl. Catal. A 231 (2001) 337]


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The 2,6-dialkyl isomer is narrower than the other isomersCan the product shape selectivity of zeolites be applied for theselective alkylation of naphthalene to the 2,6-isomer ?

FAU MORBEA

6.4 x 7.6 /3D 7.4 /3D

Cages, 13.2 6.5 x 7 /1D

Framework structures and pore characteristicsof some conventional zeolites


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Table 3

Isopropylation of naphthalene over conventional zeolites (from Ref. 22)_______________________________________________________________________Catalyst SiO2/Al2O3 Conversion Product Distribution of di-isopropyl naphthalene,%

Ratio % 1,3- 1,4- 1,5- 1,6- 1,7- 2,6- 2,7-_______________________________________________________________________

HZSM-5 70 1.0 - - - -- -HY 7.3 96.1 23.7 0.6 0.2 6.8 4.9 32.6 31.2

HL 6.1 95.1 39.9 7.9 6.7 15.3 16.3 6.7 7.2HM 25.3 68.3 5.3 3.8 1.9 7.1 6.1 50.8 24.9

A comparison of the activity and selectivity of conventionalZeolites in the isopropylation of naphthalene

* HY and HL zeolites are extremely active, but not selective to 2,6 DIPN* HL has a wider product distribution, rather a poor selectivity to 2,6 and 2,7 DIPN

* HM is the most selective (for both 2,6 and 2,7 DIPN), but less active under identical

Conditions of reaction

[Y. Sugi et al., Recent Res.Dev.Mat.Sci.Engg., 1 (2002) 395]

Isopropylation of naphthalene over conventional zeolites

Isopropylation of Biphenyl


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Isopropylation of Biphenyl

2-IBP

3-IBP

4-IBP

+

3,2'-IBP 3,3'-IBP

+

2,4'-IBP2,2'-IBP

4,4'-IBP

3,4'-IBP

+

Three monoalkyl and six dialkyl biphenyls are possible

S l ti it f 4 4 DIPB i lit i th i l ti f


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0

20

40

60

80

100

CI

T-1

CIT-5

SSZ-31

SAPO-5

UTD-1

SSZ

-24

ZSM

-12

HM

ZSM-22H

HL

HYS

electivityof4,4

'-DIPN(%

)

Reaction conditions: Temp.= 250oC; C3= pressure = 0.8 Mpa

(Y. Sugi et al., Catal. Surveys Japan, 5 (2001) 43)

Selectivity for 4,4-DIPB over various zeolites in the isopropylation ofbiphenyl


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ISOMERIZATION REACTIONS

X l i i ti


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Xylene isomerization

Catalysts are usually bifunctional typesTypical examples: Pt-ZSM-5, Pt-mordenite& Pt-(silica)-alumina


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Xylene isomerization

CH3

CH3

CH3

CH3

+

CH3

CH3

+

CH3

CH3

Zeolite

Catalyst:ZSM-5, Mordenite; MAPO; SiO2-Al2O3 loaded with Pt

XYLOFINING developed by NCL-ACC-IPCL in 1986

Mechanism

i i i i i


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Restricted transition state shape-selectivity

RTS selectivity is also responsible for:

- Resistance of medium pore zeolites to coking

In the isomerization of m-xylene,bimolecular disproportionation intobenzene and TMB also take place

Use of zeolites with the right pore-size or cavities to prevent the

bimolecular transition stateformation increases isomerizationselectivity

P d ti f l


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(bp, 110 - 140C)

Reforming(Pt-Re-Sn/Alumina)

Fraction-ation

Xylene iso-merizatrion(Pt-ZSM-5;Pt-Mord.;Pt-MAPO)

Fraction-ation

Arom.Extraction

TransalkylationPt/Mordenite

Mol. SieveSeparation(PAREX)

Benzene

Toluene

Xylenes + EB

C9+Arom.

DisproportionationPt/Mordenite

Naphtha

o-Xylene

p-Xylene

m- + EB

Raffinate

Production of xylenes

Disproportionation and transalkylation reactions


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CH3

CH3

CH3

Catalyst Toluenedisproportionation

C9+ aromaticstransalkylation

CH3

CH3

CH3

+

CH3

CH3

CH3

Catalyst

Disproportionation and transalkylation reactions

Catalytic reforming for aromatics production


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Catalytic reforming for aromatics production

Desired reactions inCatalytic reforming

60-90

C cut for benzene

90-110C cut for toluene

110-140C for xylenes

The reactions are:

S l ti id ti ti


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Selective oxidation reactions

Current method is the oxidation of cyclohexanolwith HNO3 producing N2O

Noyoris method is oxidation of cyclohexene inbiphasic medium (commercially attractive)

Frosts method uses an enzyme and a renewable

raw materialglucose

Oxidation of n-hexane or cyclohexane over MAPOs

Adipic acid


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OH

+

O

O2

-H2

H2

HNO3

COOH

COOH

+N2O

Current process for adipic acid

Enviro-friendly routes for adipic acid


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COOH

COOH COOH

COOH O

OH

OH

OH

OHOH

(current route)

(Noyori's route)

adipic acid muconic acid

D-glucose

(Biocatalysis; Frost's route)

Enviro-friendly routes for adipic acid

O2 COOH

COOH

O2

R. Noyori, Science 281 (1998) 1646 K.M. Draths & J.W. Frost, JACS 120 (1998)10545

J. M. Thomas & R. Raja,Chem. Commun.Feature Article, 675 ( 2001)

Oxidation of alkanes


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The present route for acetic acid and vinyl acetate

manufacture is:

CH4 H2 + CO CH3OH (+CO) CH3COOH -- (1)C2H6 C2H4 ------ (2)C2H4 + CH3COOH CH2CHOCOCH3 (VA) ----- (3)Direct vapour-phase catalytic oxidation of ethane toHOAc and ethylene and vinyl acetate:

C2H6 CH3COOH + C2H4 CH2CHOCOCH3SABIC

- Avoiding multi-step processes- Alterante cheaper raw materials

Oxidation of alkanes

Use of alternate raw materials


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Use of alternate raw materialsselective oxidation reactions that need to be commercialized

1. Propane to acrolein and acroleic acid(presently use propylene)2. Butane to methacrylic acid(presently butene is used)

3. Propane to acrylonitrile(propylene used at present)4. Ethane to vinyl chloride(ethylene is used at present)

5. Methane to methanol to HCHO and HCOOH(Syn gas used at present)6. n-Hexane to adipic acid(Cyclohexanol and nitric acid used)

Phenol production


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H3PO4/zeolite

O

N2O

FeZSM-5

TS1

O

OOH

OH

H2O2/

(Benzene) (Cumene) (Cumene hydroperoxide)

(phenol)

Phenol production


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TS-1 MFI Sumitomo

Production ofCaprolactamw.o. (NH4)2SO4

co-production

- Less polluting- Less number

of steps- Benign reagents


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Environmentally safe route to polycarbonate

Route 2

CO O

O

CH3H3C H2O

DMC+ OH2Transesterification

DPC+ CH3OH

2 CH3OH + CO + 1/2 O2+

DMC

OHHO

BPA

+ CO O

O

473 - 593 KCatalyst

BPC + 2

DPC

OH

Route 1

OONa Na + COCl2

NEt3CO O

O

( )n

Bisphenol-A (BPA)(Na salt)

Bisphenol-A Polycarbonate (BPC)

Conventional routes to polycarbonate


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CH 2 CH 2 + 1/2 O 2CH 2 CH 2

O (EO)

1

CH 2 CH 2 + CO 2CH 2 CH 2

OOC

O

2

(EC)

CH 2 CH 2

O OC

O (EC)

+ 2 MeOH MeOCOMe

O

+ HOCH 2CH 2OH 3

(DMC) (MEG)

MeOCOPh

O

2

(MPC)

PhOCOPh

O(DPC)

MeOCOMe

O(DMC)

+ 4

PhOCOPh

O(DPC)

+ HO C HO

CH 3

CH 3

O C O

CH 3

CH 3

C

O

OPhH + PhOH 5

n

The greenAsahi-KaseiPolycarbonateprocess O

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