AU644666B2 - Process for making ethanol solutions of alkyl half-esters of copolymers of maleic anhydride and a c1-c4 alkyl vinyl ether - Google Patents

Description

0PI DATE 30/03/92 AOJP DATE 14/05/92 ADPLN. ID 81084 91 PCT NUMBER PCT/11S91/04649 INTERNA'IiA-n i,,.in.aj, u iu ui, LEnr inc rm tAc LUUIrtCKA IIUN TREATY (PCT) (51) International Patent Classification 5 (11) International Publication Number: WO 92/04405 C08K 5/05, C08F 216/ 1 2 Al C08F 222/16 (43) International Publication Date: 19 March 1992 (19.03.92) (21) International Applicatio!. Number: PCT/US91/04649 (81) Designated Statos: AT (European patent), AU, BE (European patent), CA, CH (European patent), DE (Euro- (22) International Filing Date: 28 June 1991 (28.06.91) pean patent), DK (European patent), ES (European patent), FR (European patent), GB (European ;atent), GR (European patent), IT (European patent), JP, LU (Euro- Priority data: pean patent), NL (European patent), SE (European pa- 574,843 30 August 1990 (30.08.90) US tent).

(71)Applicant: ISP INVESTMENTS INC. [US/US]; 818 Published Washington Street, Wilmington, DE 19801 With international search report.

(72) Inventors: TAZI, Mohammed 33 Claremont Terrace, Wayne, NJ 07470 LOGIN, Robert, B. 137 Page Drive, Oakland, NJ 07436 (US).

(74) Agents: MAUE, Marilyn, J. et al.; GAF Corporation, Patent Dept., Building No. 10, 1361 Alps Road, Wayne, NJ 6 4 07470 (US).

(54) Title: PROCESS FOR MAKING ETHANOL SOLUTIONS OF ALKYL HALF-ESTERS OF COPOLYMERS OF MA- LEIC ANHYDRIDE AND A CI-C 4 ALKYL VINYL ETHER (57) Abstract What is described herein is a process for making ethanol solutions of alkyl half-esters of copolymers of maleic anhydride and a Ci-C 4 alkyl vinyl ether which are benzene and acetone-free. The invention is characterized by precharging a reactor with excess CI-C 4 alkyl vinyl ether as both monomer reactant and solvent, and a free radical polymerization intiator, at a reaction temperature; feeding the alkyl half-ester of maleic anhydride formed by reaction of substantially one mole of maleic anhyd. ide and substantially one mole of alkanol into the precharged reactor to form the desired alkyl half-ester of the alternating copolymer of maleic anhydride and the CI-C 4 alkyl vinyl ether in excess alkyl vinyl ether as solvent; cooling the reactor to room temperature; and introducing ethanol solvent into the reactor and removing excess alkyl vinyl ether to form the desired half-ester copolymer in ethanol solution.

WO 92/04405 P(7r/US91/04649 1 PROCESS FOR MAKING ETHANOL SOLUTIONS OF ALKYL HALF-ESTERS OF COPOLYMERS OF MALEIC ANHYDRIDE AND A C 1

-C

4 ALKYL VINYL ETHER This invention relates to ethanol solutions of alkyl half-esters of maleic anhydride and a C 1

-C

4 alkyl vinyl ether, and, more particularly, to a process for making such solutions which are benzene and acetone-free.

Several processes are available for making ethanol solutions of alkyl, e.g. butyl half-esters of maleic anhydride and a C 1

-C

4 alkyl vinyl ether. For example, such solutions can be obtained from powders of maleic acid-C 1

-C

4 alkyl vinyl ether copolymers prepared by copolymerization of maleic anhydride and a C 1

-C

4 alkyl vinyl ether in benzene. In this process, such powders are half-esterified in excess butanol, followed by introduction of ethanol solvent and removal of remaining butanol.

However, since this method requires the use of a considerable excess of butanol, some butanol may remain in the product. Furthermore, the half-ester must be heated to distill out excess butanol, and, under these conditions, a considerable amount of the corresponding ethyl half-ester copolymer is formed by transesterification of the half-butanol copolymer solution. In summary, the presence of undesirable benzene, butanol and ethyl half-ester in the solution product is objectionable from a commercial standpoint.

WO 92/04405 PCTUS91/04649 2 Another method known in the art avoids the use of benzene but introduces acetone as a solvent into the system. Residual acetone, free butanol and ethyl half-ester copolymer are found in the solution of this product. These solvents also are objectionable in commercial compositions, such as hair formulations.

Furthermore the ethyl half-ester copolymer is less compatible with hydrocarbon propellants used in aerosol hair treatment products than the butyl half-ester copolymer.

For these and other reasons, it is desired to provide a new and improved process for making ethanol solutions of alkyl half-esters of copolymers of maleic anhydride and a C 1

-C

4 alkyl vinyl ether, which process overcomes the disadvantages of prior art methods of manufacturing such products.

What is described herein is a process for making ethanol solutions of alkyl, e.g. butyl half-esters of copolymers of maleic anhydride and a C 1

-C

4 alkyl vinyl ether which are benzene and acetone-free. The invention is characterized by precharging a reactor with excess

C

1

-C

4 alkyl vinyl ether as both monomer reactant and solvent, and a free radical polymerization initiator, at a reaction temperature; feeding the alkyl, e.g. butyl half-ester of maleic anhydride formed by reaction of substantially one mole of maleic anhydride and substantially one mole of butanol into the precharged reactor to form the desired alkyl half-ester of the alternating copolymer of maleic anhydride and the CI-C 4 alkyl vinyl ether in excess alkyl vinyl ether as solvent; cooling the reaction product to room temperature; and introducing ethanol solvent into the reactor and removing excess alkyl vinyl ether, thereby to form the desired ethanol solution of the alkyl half-ester copolymer.

WO 92/04405 PCI/US91/04649 3 In accordance with the present invention, there is provided a process for making ethanol solutions of alkyl, e.g. lower alkyls such as butyl half-esters of copolymers of maleic anhydride and a C 1

-C

4 alkyl vinyl ether which are benzene and acetone-free. In this method, a suitable reactor is provided with appropriate inlet tubes, agitation means, and heater and temperature control means. The reactor is first purged with nitrogen to remove air from the system. Generally three separate purges are employed, at about 3 bars pressure and about 40 0 C. Then the reactor is precharged with a substantial excess of C 1

-C

4 alkyl vinyl ether reactant, preferably methyl vinyl ether, which also functions as a solvent to facilitate agitation of the contents of the reactor before and during the polymerization. The solvent then is heated to a reaction temperature, generally about 50-90 0 preferably about 58 0 -65 0 C. Thereafter a polymerization initiator is charged into the reactor, suitably in a solution with some alkyl vinyl ether solvent. Any suitable initiator known in the art may be used including but not limited to peroxides.

Tertiary butyl or tertiary amylperoxy pivalate are preferred. The concentration of initiator may vary widely, suitably about 0.05 to 2% by weight of maleic anhydride is used, although about 0.2% by weight usually will suffice for carrying out an effective polymerization.

The first step in the process of the invention is the preparation of the alkyl, e.g. butyl half-ester of maleic anhydride (BMA). This monomer is made by direct half-esterification of one mole of maleic anhydride and one mole of butanol at about 80 C. for 3-4 hours. This reaction consumes all of the butanol reactant.

WO 92/04405 PCT/US91/04649 4 The BMA monomer then is copolymerized with the

C

1

-C

4 alkyl vinyl ether reactant by feeding the liquid half-ester into the precharged reactor. Generally about one mole of BMA is copolymerized with about 6-10 moles of alkyl vinyl ether, preferably methyl vinyl ether, at about a 20% solids level. The product is an alternating copolymer of alkyl vinyl ether and BMA, which is the desired butyl half-ester of maleic anhydride and alkyl vinyl ether, in excess alkyl vinyl ether only.

Thereafter the reactor is cooled to room temperature, and ethanol is introduced while excess methyl vinyl ether is vented 5 thereby forming an ethanol solution of the butyl half-ester as a 50% solids solution. Since removal of the methyl vinyl ether occurs below room temperature and solvent exchange of ethanol for methyl vinyl ether is carried out at room temperature, transesterification of ethanol with BMA to form the ethyl half-ester does not occur. In addition, no extraneous benzene or acetone solvent is present in the final product, and excess butanol or substantial amounts of ethyl half-ester are not present.

The invention will now be described by reference to the following example.

WO 92/04405 P(rUS91/04649 5

EXAMPLE

A reactor equipped with suitable inlet tubes and agitation means and temperature controllers was purged with

N

2 at 3 bars pressure and 40 0 C. The purged reactor then was precharged with 180.5 g. of methyl vinyl ether and heated to 60 0 -65 0 C. Then 2.7 g. of a 75% solution of tertiary amylperoxy pivalate was added. Then 86 g. of monobutyl maleate, i.e. the half-butyl ester of maleic anhydride, prepared by reacting one mole of butanol with one mole of maleic anhydride at 80 0 C. for 3-4 hours, was added over a 3 hour period while agitating the mixture solids). The reaction product was held for 1 hour at 60 0

C.

and the reactor was cooled to 25 0 -30 0 C. Then excess methyl vinyl ether was vented slowly while adding ethanol to form a 50% solids solution of the butyl half-ester copolymer in ethanol.

Claims (8)

1. A process for making ethanol solutions of alkyl half-esters of copolymers of maleic anhydride and a C 1 -C 4 alkyl vinyl ether which comprises: precharging a reactor with excess C1-C 4 alkyl vinyl ether as both monomer reactant and solvent and a free radical polymerization initiator at a reaction temperature of about 50 0 -90 0 C., feeding the alkyl half-ester of maleic anhydride formed by reaction of substantially one mole of maleic anhydride and substantially one mole of alkanol into the precharged reactor to form the desired alkyl half-ester copolymer reaction product, cooling the reaction product to room temperature, and introducing ethanol into the reactor and removing excess alkyl vinyl ether to form the desired ethanol solution of the alkyl half-ester copolymer.

2. A process according to claim 1 wherein said C 1 -C 4 alkyl vinyl ether is methyl vinyl ether.

3. A process according to claim 1 wherein said desired product is benzene and acetone-free and is substantially alkanol and ethyl half-ester copolymer-free. WO 92/04405 PCr/UkS91/04649 7

4. A process according to claim 1 wherein said alkanol is butanol.

A process according to claim 1 wherein the polymerization temperature is about 58 0 -65 0 C.

6. A process according to claim 1 wherein the copolymerization is carried out with about one mole of the butyl half-ester of maleic anhydride to about 6-10 moles of methyl vinyl ether.

7. A process according to claim 1 wherein the reaction product is about a 20% solids solution in excess alkyl vinyl ether.

8. A process according to claim 1 wherein the solution product has about 50% solids therein. INTERNATIONAL SEARCH REPORT International Application No PCT/US91/04649 I. CLASSIFICATION OF SUBJECT MATTER (if several classification symools apply, indicate all) 3 Acccrding to International Patent Classification (IPC) or to both National Classification and IPC IPC C08K 5/05; C08F 216/12, 222/16 U.S. Cl: 524/765; 526/318, 332 II FIELDS SEARCHED Minimum Documentation Searched 4 Classfication System Classification Symools U.S. 524/765; 526/318, 332 Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included in the Fields Searched III. DOCUMENTS CONSIDERED TO BE RELZ'VMAT "1 Category Citation of Document, i with indication, where appropriate, of the relevant passages I Cale~ry Ci-tion of Document, 11 with indication, where appropiate, of the relevant Passages IT. US, A, 4,908,413 (GOERTZ ET AL.) 13 MARCH 1990; See claims 1-11. US, A, 4,939,198 (TAZI ET AL.) 03 JULY 1990; See claim 1. SRelevant to Claim No. 1 1-8 1-8 i. Spacial categories of cited documents: l document defining the general state of the art which is not considered to be of particular relevance earlier document but published on or after the international filing date document which may throw doubts on pliirity claim(s) or which is cited to establish the publication date of another citation or other special reason (as specified) document referring to an oral disclosure, use, exhibition or other means document published prior to the international filing date but later than the priority date claimed later document published after the international iling oate or priority date and not in conflict with the application ut cited to understand the principle or theory underlying tIe invention document of particular relevance: the claimed invention cannot be considered novel or cannot be cons:aered to involve an inventive step document of particular relevance: the claimed invent-on cannot be considered to involve an inventive step when tre document is combined with one or more other such o;:u- ments, such combination being obvious to a person skileo in the art. document member of the same patent family IV. CERTIFICATION Date of the Actual Comoletion of the International Search s Datfof Mailing of this International Search Repon 09'AUGUST 1991 28AUG 1991 International Searching Authority I Signature of ul ot or ISA/US W. C. Chen- Form PCT/ISA/210 (second sheet) (May 1986)