CA1115446A - Process - Google Patents

Process

Info

Publication number
CA1115446A
CA1115446A CA312,576A CA312576A CA1115446A CA 1115446 A CA1115446 A CA 1115446A CA 312576 A CA312576 A CA 312576A CA 1115446 A CA1115446 A CA 1115446A
Authority
CA
Canada
Prior art keywords
terephthalic acid
glycol
suspension
reaction vessel
reactor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA312,576A
Other languages
French (fr)
Inventor
Lawrence E. Shelley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Goodyear Tire and Rubber Co
Original Assignee
Goodyear Tire and Rubber Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Goodyear Tire and Rubber Co filed Critical Goodyear Tire and Rubber Co
Application granted granted Critical
Publication of CA1115446A publication Critical patent/CA1115446A/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/0015Feeding of the particles in the reactor; Evacuation of the particles out of the reactor
    • B01J8/0025Feeding of the particles in the reactor; Evacuation of the particles out of the reactor by an ascending fluid
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/78Preparation processes
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/78Preparation processes
    • C08G63/785Preparation processes characterised by the apparatus used

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Polyesters Or Polycarbonates (AREA)

Abstract

PROCESS
Abstract of the Disclosure This invention concerns a method of charging dry terephthalic acid into a reactor which may contain glycol and be under elevated pressure and elevated temperature. According to the invention a suspension of terephthalic acid in a gas such as nitrogen is formed and this suspension is charged into the reactor.

Description

~1544~5 This invention relates to a process for charging dry terephthalic acid to a reactor. More partic-ularly the invention relates to a process for adding dry -terephthalic acid to a reactor which contains glycol.
In the preparation o~ polyethylene terephthalate from glycol and terephthalic acid it is desirable to use these materials in the molar ratio of 1:1 or as closely as possible to minimi~e side reactions such as ether formation and to avoid having to recover unused glycol. In a batch process terephthalic acid may be charged to the reactor by pumping a premixed glycol/terephthalic acid paste to the reactor or by adding preweighed amounts of reactants ta a partially cooled vessel at atmospheric pressure.
Once the raw materials have been added the reactor may be brought to the desired pressure and temperature for the esterification reaction.
In a continuous process the esterification reactor must be maintained at elevated temperatures and pressure while the reactants are continuously metered into the vessel. Customarily this has been achieved by using a slurry pump which is capable of pumping a paste of glycol and terephthalic acid into a pressurized vessel. This method is limited by the fact that the paste viscosity gets very high when the ratio of glycol/terephthalic acid is low. The prior art has not provided a satisfactory solution to the problem of adding terephthalic acid to a reactor which contains hot glycol and may be under pressure.
According to the present invention glycol and terephthalic acid may be added to the esterification , .
- . . , .. .. , , -~ ~15 ~

reactor separately. According to this invention terephthalic acid is mixed with a gas such as nitrogen under pressure'to form a suspension of terephthalic acid in the gas and this suspension is metered under pressure into the esterification reactor. The'glycol is separately pumped into the'reactor in the proper amount to provide the'desired ratio of glycol to terephthalic acid in the esterification reactor. Normally the esterification reactor is maintained under pressure and 10' the reaction is run at a temperature in the range of about 250 to 270 C. Accordingly, in a continuous process for reacting terephthalic acid with liquid glycol in an esterification reaction vesseI maintained at elevated temperatures and pressures the'improvement comprises forming a suspension of dry, solid particulate terepht~alic acid in nitrogen gas under pressure, maintaining said suspension under pressure and charging said suspension into said reaction vessel to which glycol is being charged separately.
The'invention is illustrated in the following example'which is more fully explained by reference to the accompanying drawing which shows the flow of materials in the system. In the'drawing it is shown that terephthalic acid is passed from storage (not shown) to an intermediate hopper 1 from which it is discharged through a double valve system 2 and 3 into weigh'tank 4 where it is deposited on porous diaphragm 5 which is spaced apart from the bottom of the weigh tank 4. ~itrogen gas from storage (not shown~ is passed into the bottom of weigh tank 4 through conduit 6 and activator valve 7 at a point below porous disphragm 5.

~!j,C

~ ~ 5 4~

The nitrogen gas is under a pressure of about 80 psi-which is sufficiently great that it passes through the diaphragm and forms a suspension of terephthalic ~cld and nitrogen gas. The suspension is passed through conduit 8 and discharge valve 9 into esterification reactor 10 which is equipped with a separation column 11, a condenser 12 and an agitator 13. As terephthalic acid is passed into esterification reactor lO ethylene glycol is pumped through .

rc ,. , ..... .;

conduit 14 from storage, not shown, in the proper amount to provide the desired ratio of glycol to terephthalic acid.
Esterification reactor 10 is maintained at a pressure of 70 psig and a temperature of about 270 C. Excess nitrogen gas 1s vented out of esterification reactor 10 through the column llo In continuous operation low molecular weight polymer is continuously withdrawn from esterification reactor 10 in an amount about equal to the amount of terephthalic acid and glycol charged into the esterification reactor 10.
The above description shows that dry terephthalic acid can be charged into a vessel maintained at high temperature and pressure and that the terephthalic acid can be charged continuously. The esterification reaction is carried out using low ratios of glycol to acid ... .
preferably in the range of from about 1.05:1 to 1.7:1.
Lower ratios than 1:1 can be charged successfully by use of - the present system.
The invention provides several advantages over processes shown in the prior art. Glycol and terephthalic acid may be charged into a reactor in any desired ratios.
` In addition~ the reactant vessel may be maintained at a ~ high temperature and pressure while the dry terephthalic - acid is being charged. If desired~ two or more weigh tanks can be used to ensure that the terephthalic acid can charge continuously~ The reactants~ particularly the glycol~ can ~; be preheated to a desired temperature before being charged into the reactor and this shortens the reaction time.
Charglng terephthalic acid to a reactor by the ... ..
.. . .. ~.- -s~

present system is accurate and reproducible. It eliminates the need for preparing slurries or pastes which when low ratios of glycol to acid are used are very viscous and difficult to convey into the reaction vessel, particularly when the vessel is under pressure.
While certain representative embodiments ànd details have been shown for the purpose of illustrating the invention it will be apparent to those skilled in this art that various changes and modifications may be made therein without departlng from the sp1r1t or soope of the lnvention. ~, .' ' ' , : . .
.

. ' , .

.. . .. .- .. ... .

Claims (3)

1. In a continuous process for reacting terephthalic acid with liquid glycol in an esterification reaction vessel maintained at elevated temperatures and pressures the improvement which comprises forming a suspension of dry, solid particulate terephthalic acid in nitrogen gas under pressure, maintaining said suspension under pressure and charging said suspension into said reaction vessel to which glycol is being charged separately.
2. The improvement of claim 1 wherein the suspension of dry, solid particulate terephthalic acid in the nitrogen gas is maintained and charged to said reaction vessel at a pressure higher than that maintained in said reaction vessel.
3. The improvement of claim 2 wherein the liquid glycol and suspended dry, solid terephthalic acid are charged to the reaction vessel in amounts to provide a molar ratio of glycol to acid ranging from about 1:1 to about 1.7:1 in said reaction vessel.
CA312,576A 1977-12-16 1978-10-03 Process Expired CA1115446A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US86133377A 1977-12-16 1977-12-16
US861,333 1977-12-16

Publications (1)

Publication Number Publication Date
CA1115446A true CA1115446A (en) 1981-12-29

Family

ID=25335519

Family Applications (1)

Application Number Title Priority Date Filing Date
CA312,576A Expired CA1115446A (en) 1977-12-16 1978-10-03 Process

Country Status (8)

Country Link
JP (1) JPS5490138A (en)
BR (1) BR7808100A (en)
CA (1) CA1115446A (en)
DE (1) DE2850951A1 (en)
FR (1) FR2411631A1 (en)
GB (1) GB2010294B (en)
IT (1) IT1111091B (en)
NL (1) NL188096C (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0958857A1 (en) * 1998-05-14 1999-11-24 Bp Chemicals S.N.C. Process for the introduction of a catalyst into a gas phase polymerisation reaction
US6906164B2 (en) 2000-12-07 2005-06-14 Eastman Chemical Company Polyester process using a pipe reactor
EP1453883B1 (en) 2000-12-07 2012-11-21 Grupo Petrotemex, S.A. de C.V. Low cost polyester process using a pipe reactor
US7943094B2 (en) 2006-12-07 2011-05-17 Grupo Petrotemex, S.A. De C.V. Polyester production system employing horizontally elongated esterification vessel
US7649109B2 (en) 2006-12-07 2010-01-19 Eastman Chemical Company Polyester production system employing recirculation of hot alcohol to esterification zone
US7863477B2 (en) 2007-03-08 2011-01-04 Eastman Chemical Company Polyester production system employing hot paste to esterification zone
US7847053B2 (en) 2007-07-12 2010-12-07 Eastman Chemical Company Multi-level tubular reactor with oppositely extending segments
US7829653B2 (en) 2007-07-12 2010-11-09 Eastman Chemical Company Horizontal trayed reactor
US7842777B2 (en) 2007-07-12 2010-11-30 Eastman Chemical Company Sloped tubular reactor with divided flow
US7868129B2 (en) 2007-07-12 2011-01-11 Eastman Chemical Company Sloped tubular reactor with spaced sequential trays
US7872090B2 (en) 2007-07-12 2011-01-18 Eastman Chemical Company Reactor system with optimized heating and phase separation
US7868130B2 (en) 2007-07-12 2011-01-11 Eastman Chemical Company Multi-level tubular reactor with vertically spaced segments
US7872089B2 (en) 2007-07-12 2011-01-18 Eastman Chemical Company Multi-level tubular reactor with internal tray
US7858730B2 (en) 2007-07-12 2010-12-28 Eastman Chemical Company Multi-level tubular reactor with dual headers

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3393944A (en) * 1966-10-25 1968-07-23 Petrocarb Inc Method for pneumatically injecting solid particles into a high pressure zone
US4020049A (en) * 1967-09-14 1977-04-26 The Goodyear Tire & Rubber Company Process for preparing polyester resin
DE1667010C3 (en) * 1967-12-23 1975-10-09 Dynamit Nobel Ag, 5210 Troisdorf Method and device for the reliable filling of oxidation-sensitive materials
NL7016364A (en) * 1970-10-21 1972-04-25
ES419510A1 (en) * 1972-12-15 1976-04-16 Huels Chemische Werke Ag Process for the esterification of terephthalic acid in the gas phase
US4018671A (en) * 1975-01-14 1977-04-19 Marathon Oil Company Intermittent catalyst addition system

Also Published As

Publication number Publication date
BR7808100A (en) 1979-08-07
FR2411631A1 (en) 1979-07-13
JPS5490138A (en) 1979-07-17
GB2010294B (en) 1982-08-11
DE2850951A1 (en) 1979-06-21
GB2010294A (en) 1979-06-27
JPS6317089B2 (en) 1988-04-12
NL7812037A (en) 1979-06-19
NL188096C (en) 1992-04-01
DE2850951C2 (en) 1989-04-20
NL188096B (en) 1991-11-01
FR2411631B1 (en) 1982-04-30
IT1111091B (en) 1986-01-13
IT7852265A0 (en) 1978-12-12

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