CA1070893A - Process for polymerization of 2-pyrrolidone and product produced - Google Patents
Process for polymerization of 2-pyrrolidone and product producedInfo
- Publication number
- CA1070893A CA1070893A CA245,567A CA245567A CA1070893A CA 1070893 A CA1070893 A CA 1070893A CA 245567 A CA245567 A CA 245567A CA 1070893 A CA1070893 A CA 1070893A
- Authority
- CA
- Canada
- Prior art keywords
- polymer
- pyrrolidone
- polymerization
- white
- catalyst
- 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
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
- C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
- C08G69/08—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from amino-carboxylic acids
- C08G69/14—Lactams
- C08G69/24—Pyrrolidones or piperidones
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
- Polyamides (AREA)
- Polyoxymethylene Polymers And Polymers With Carbon-To-Carbon Bonds (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to an improved method of producing a polymer of 2-pyrrolidone suitable for melt spinning into a white fiber employing an alkaline catalyst and sulfur dioxide as the co-catalyst. The method embodies the use of SO2 within the preferred range of from 0.01 to 0.03 moles of SO2 per moles of 2-pyrrolidone coupled with a polymer color removal treat-ment, after washing the polymer cake to remove unchanged monomer and alkali. This color removal consists of an oxidizing rinse, employing a liquid oxidant such as H2O2 and followed after a water wash, by a reducing bath consisting for example of a solution of sodium metabisulfite and followed again by a water wash. The polymer resulting from this method is a white thermally stable resin capable of being melt spun into white fiber.
The present invention relates to an improved method of producing a polymer of 2-pyrrolidone suitable for melt spinning into a white fiber employing an alkaline catalyst and sulfur dioxide as the co-catalyst. The method embodies the use of SO2 within the preferred range of from 0.01 to 0.03 moles of SO2 per moles of 2-pyrrolidone coupled with a polymer color removal treat-ment, after washing the polymer cake to remove unchanged monomer and alkali. This color removal consists of an oxidizing rinse, employing a liquid oxidant such as H2O2 and followed after a water wash, by a reducing bath consisting for example of a solution of sodium metabisulfite and followed again by a water wash. The polymer resulting from this method is a white thermally stable resin capable of being melt spun into white fiber.
Description
lQ7(~893 Barnes, N~y and Nummy first described and patented the polymerization product of 2-pyrrolidone in 1953 in U.S. Patent No. 2,638,463. This resulted from an application filed in 1951 which described the polymerization of 2-pyrrolidone in the presence of an alkaline polymerization catalyst such as potassium hydroxide.
The yield, however, was not commercially acceptable and the vis-cosity of the polymer too low to permit melt spinning. Later attempts at increasing the molecular weight of the polymer produced are reflected in Barnes U.S. Patent No. 2,809,958 of October 15,1957 and of William Ney and Milton Crowther in U.S. Patent No. 2,739,959 of March 27, 1956, wherein, catalyst activators such as acyl halide or acyl pyrrolidones such as acetyl pyrrolidone are suggested to solve the problem. Taber, as described in U.S. Patent No. 3,174,951 granted March 23, 1965, bubbled S02 gas through the reaction mixture.
This produced a polymer having a much higher molecular weight but under the conditions used for commercial production to give a good yield of polymer, the product has an objectionable yellow color which renders it unsuitable for use in synthetic fibers.
Still later, in March of 1973, Carl Barnes obtained a patent on the use of CO2 as a co-catalyst which gave a polymer of high molecular weight suitable for melt spinning into synthetic fibers. This polymer was pure white in color. This patent issued March 20, 1973 as U.S. Patent No. 3,721,652.
The problem of eliminating the yellow color from the polymer formed when using SO2 was studied by Jarovitzky who obtained a U.S. Patent No. 3,681,294 which describes the use of sodium sulfite - bisulfite combinations in an effort to remove the color. Finally, applicant began a series of experiments which led to a method by which one can obtain a pure white polymer of 2-pyrrolidone while using SO2 as the co-catalyst.
It is a primary object of the invention to provide a method of making pure white polymers of 2-pyrrolidone when employiny S02 as the co-catalyst.
The invention described herein comprises the polymeriza-tion of 2-pyrrolidone at 50C. using an alkaline catalyst such as potassium hydroxide and S02 as the co-catalyst in a preferred amount of between 0.01 and 0.03 mols per mol of 2-pyrrolidone coupled with a two-step treatment of the polymer formed. The yellow polymer formed in the polymerization step, after washing to remove unconverted monomer and alkali, is then first treated with an oxidizing agent such as hydrogen peroxide or potassium persulfate. After washing with water the now white polymer is further treated with a reducing agent such as a solution of sodium metabisulfite, Na2S205. The polymer after washing with water and drying is now thermally color stable retaining its white color when heated to high temperatures.
This above result lS most unexpected and surprising because when the Taber process is run at commercial polymerization temperature i.e. 50C. with an S02 catalyst activator a yellow polymer results. When one seeks to remove this color by bleaching - out with a bleach such as hydrogen peroxide the brown color fades away at room temperature but when the polymer is heated to melt spinning temperatures the polymer browns to a color which is deeper than before bleaching.
However, it has been found that if one contacts the bleached resin with a reducing agent and washes with water some-thing occurs which renders the polymer permanently free of dis-coloration no matter how long or to what melt temperatures it is heated. This result may be related to either a change in the chemical composition of the colored impurity or its solubility or both.
The monomer of piperidone may be polymerized by a process of the foregoing examples by merely substituting the same for the pyrrolidone monomer in one of the foregoing examples In this reaction the conventional chain terminating groups may be employed as ~-pyrrolidonyl or N-piperidonyl groups or several other known chain terminating agents as described by the Taber Patent ~o. 3,174,951 especially those groups referred to in column 4,lines 14 to 38 of the Taber Patent.
The fiber products of the present invention are useful in the arts in as many applic,ations as conventional nylon-6. In this sense their use as textile fibers i5 clear and because of their ability to be melt spun as white fibers capable of being finished and dyed to any color selected they are assured of a great demand in commerce. In addition to their usage in melt spun fibers the polymers of the present invention have wide application as films or as non woven pulp which is useful as a compressed sheet for manufacture of synthetic leather in shoe manufacture.
In accordance with a broad aspect of the invention, there is provided a method of polymerization of 2-pyrrolidone in the presence of an alkaline polymerization catalyst and SO2 as a pol~merization activator to form a solid melt spinnable polymer. The method is characterized by effecting the polyme-rization in the presence of from 0.01 to 0.03 moles of SO2 polymerization activator per mole of monomer and subjecting the polymer formed to sequential treatment with first a liquid oxidizing agent and second a reducing agent to obtain a white polymer product.
The invention herein will be further more particularly illustrated by the several following examples o~ my improved method of preparing the polymer oE this invention.
100 grams of recrystallized 2-pyrrolidone was added to a 500 ml 3-necked flask equipped with a gas inlet tube, a thermometer for measuring pot temperature and a Claissen type distilling head having a thermometer for measuring the temperature of the vapor (i.e. the boiling point) connected to a condenser and a receiver having a vacuum connection. To this was added 6.6 grams of KOH of 85% assay (O.l mole based on the final pyrrolidone content)r The apparatus was then swept with dry nitrogen which was admitted through the gas inlet tube before the vacuum line was connected.
3a-~ . , ~07(~893 Then the system was evacuated to 20 mm Hg pressure and the mixture heated to form the potassium salt. After the water formed by the reaction had distilled over 15 grams of 2-pyrrolidone was distilled off or over to ensure dryness leaving 85 grams (1 mole). During the distillation of the pyrrolidone the pot temperature was 130C.
and the head temperature 125C. After the 15 grams of pyrrolidone had been distilled over the flask was cooled until the pot thermo-meter read 25C. 0.027 mole of S02 was introduced by exhausting the contents of 2 flasks each of 300 ml capacity filled with S02 under atmospheric pressure.
After the addition the syrupy mixture was poured into a polyethylene polymerization bottle and placed in an oven at 50C.
After 3 days the hard brown cake was broken up and placed in a Waring Blender with about 500 ml. of water. The finely divided polymer was washed several times with water to remove unchanged monomer and alkali. The polymer remaining was yellow.
The wet polymer was added to 400 ml of a solution of hydrogen peroxide prepared by adding 100 ml of 30% H202 to 300 ml of water. The color of the resin changed almost instantly to a strong pink which then faded to white over the next minute. After a 5 minute soak the pure white resin was washed 3 times with water and then treated for 3 minutes with 400 cc. of a solution contain-ing 50 grams of sodium metabisulfite. The resin was then rinsed 5 times with water and dried.
The resin obtained is white and as stable to heat as a polymer made with C02 as the initiator. If the metabisulfite wash is eliminated the resin, although white, rapidly darkens on heating.
The method of Example 1 was followed except that a solution of potassium persulfate was substituted for the hydrogen peroxide. A pure white product was obtained.
~Q7~893 The method of Example 1 was followed except that a saturated solution of sodium perborate was substituted for the hydrogen peroxide. A pure white product was obtained.
A sample of the resin obtained from Example 1 was placed in a capped vial and a sample of a typical C02 initiated polymer was placed in a similar vial. Both vials were put into an oven maintained at 175C. for 1/2 hour. Both samples developed a light tan color but no difference could be detected between them.
The yield, however, was not commercially acceptable and the vis-cosity of the polymer too low to permit melt spinning. Later attempts at increasing the molecular weight of the polymer produced are reflected in Barnes U.S. Patent No. 2,809,958 of October 15,1957 and of William Ney and Milton Crowther in U.S. Patent No. 2,739,959 of March 27, 1956, wherein, catalyst activators such as acyl halide or acyl pyrrolidones such as acetyl pyrrolidone are suggested to solve the problem. Taber, as described in U.S. Patent No. 3,174,951 granted March 23, 1965, bubbled S02 gas through the reaction mixture.
This produced a polymer having a much higher molecular weight but under the conditions used for commercial production to give a good yield of polymer, the product has an objectionable yellow color which renders it unsuitable for use in synthetic fibers.
Still later, in March of 1973, Carl Barnes obtained a patent on the use of CO2 as a co-catalyst which gave a polymer of high molecular weight suitable for melt spinning into synthetic fibers. This polymer was pure white in color. This patent issued March 20, 1973 as U.S. Patent No. 3,721,652.
The problem of eliminating the yellow color from the polymer formed when using SO2 was studied by Jarovitzky who obtained a U.S. Patent No. 3,681,294 which describes the use of sodium sulfite - bisulfite combinations in an effort to remove the color. Finally, applicant began a series of experiments which led to a method by which one can obtain a pure white polymer of 2-pyrrolidone while using SO2 as the co-catalyst.
It is a primary object of the invention to provide a method of making pure white polymers of 2-pyrrolidone when employiny S02 as the co-catalyst.
The invention described herein comprises the polymeriza-tion of 2-pyrrolidone at 50C. using an alkaline catalyst such as potassium hydroxide and S02 as the co-catalyst in a preferred amount of between 0.01 and 0.03 mols per mol of 2-pyrrolidone coupled with a two-step treatment of the polymer formed. The yellow polymer formed in the polymerization step, after washing to remove unconverted monomer and alkali, is then first treated with an oxidizing agent such as hydrogen peroxide or potassium persulfate. After washing with water the now white polymer is further treated with a reducing agent such as a solution of sodium metabisulfite, Na2S205. The polymer after washing with water and drying is now thermally color stable retaining its white color when heated to high temperatures.
This above result lS most unexpected and surprising because when the Taber process is run at commercial polymerization temperature i.e. 50C. with an S02 catalyst activator a yellow polymer results. When one seeks to remove this color by bleaching - out with a bleach such as hydrogen peroxide the brown color fades away at room temperature but when the polymer is heated to melt spinning temperatures the polymer browns to a color which is deeper than before bleaching.
However, it has been found that if one contacts the bleached resin with a reducing agent and washes with water some-thing occurs which renders the polymer permanently free of dis-coloration no matter how long or to what melt temperatures it is heated. This result may be related to either a change in the chemical composition of the colored impurity or its solubility or both.
The monomer of piperidone may be polymerized by a process of the foregoing examples by merely substituting the same for the pyrrolidone monomer in one of the foregoing examples In this reaction the conventional chain terminating groups may be employed as ~-pyrrolidonyl or N-piperidonyl groups or several other known chain terminating agents as described by the Taber Patent ~o. 3,174,951 especially those groups referred to in column 4,lines 14 to 38 of the Taber Patent.
The fiber products of the present invention are useful in the arts in as many applic,ations as conventional nylon-6. In this sense their use as textile fibers i5 clear and because of their ability to be melt spun as white fibers capable of being finished and dyed to any color selected they are assured of a great demand in commerce. In addition to their usage in melt spun fibers the polymers of the present invention have wide application as films or as non woven pulp which is useful as a compressed sheet for manufacture of synthetic leather in shoe manufacture.
In accordance with a broad aspect of the invention, there is provided a method of polymerization of 2-pyrrolidone in the presence of an alkaline polymerization catalyst and SO2 as a pol~merization activator to form a solid melt spinnable polymer. The method is characterized by effecting the polyme-rization in the presence of from 0.01 to 0.03 moles of SO2 polymerization activator per mole of monomer and subjecting the polymer formed to sequential treatment with first a liquid oxidizing agent and second a reducing agent to obtain a white polymer product.
The invention herein will be further more particularly illustrated by the several following examples o~ my improved method of preparing the polymer oE this invention.
100 grams of recrystallized 2-pyrrolidone was added to a 500 ml 3-necked flask equipped with a gas inlet tube, a thermometer for measuring pot temperature and a Claissen type distilling head having a thermometer for measuring the temperature of the vapor (i.e. the boiling point) connected to a condenser and a receiver having a vacuum connection. To this was added 6.6 grams of KOH of 85% assay (O.l mole based on the final pyrrolidone content)r The apparatus was then swept with dry nitrogen which was admitted through the gas inlet tube before the vacuum line was connected.
3a-~ . , ~07(~893 Then the system was evacuated to 20 mm Hg pressure and the mixture heated to form the potassium salt. After the water formed by the reaction had distilled over 15 grams of 2-pyrrolidone was distilled off or over to ensure dryness leaving 85 grams (1 mole). During the distillation of the pyrrolidone the pot temperature was 130C.
and the head temperature 125C. After the 15 grams of pyrrolidone had been distilled over the flask was cooled until the pot thermo-meter read 25C. 0.027 mole of S02 was introduced by exhausting the contents of 2 flasks each of 300 ml capacity filled with S02 under atmospheric pressure.
After the addition the syrupy mixture was poured into a polyethylene polymerization bottle and placed in an oven at 50C.
After 3 days the hard brown cake was broken up and placed in a Waring Blender with about 500 ml. of water. The finely divided polymer was washed several times with water to remove unchanged monomer and alkali. The polymer remaining was yellow.
The wet polymer was added to 400 ml of a solution of hydrogen peroxide prepared by adding 100 ml of 30% H202 to 300 ml of water. The color of the resin changed almost instantly to a strong pink which then faded to white over the next minute. After a 5 minute soak the pure white resin was washed 3 times with water and then treated for 3 minutes with 400 cc. of a solution contain-ing 50 grams of sodium metabisulfite. The resin was then rinsed 5 times with water and dried.
The resin obtained is white and as stable to heat as a polymer made with C02 as the initiator. If the metabisulfite wash is eliminated the resin, although white, rapidly darkens on heating.
The method of Example 1 was followed except that a solution of potassium persulfate was substituted for the hydrogen peroxide. A pure white product was obtained.
~Q7~893 The method of Example 1 was followed except that a saturated solution of sodium perborate was substituted for the hydrogen peroxide. A pure white product was obtained.
A sample of the resin obtained from Example 1 was placed in a capped vial and a sample of a typical C02 initiated polymer was placed in a similar vial. Both vials were put into an oven maintained at 175C. for 1/2 hour. Both samples developed a light tan color but no difference could be detected between them.
Claims (3)
1. In the polymerization of 2-pyrrolidone in the presence of an alkaline polymerization catalyst and SO2 as a polymerization activator to form a solid melt spinnable polymer, the improvement which comprises effecting the polymerization in the presence of from 0.01 to 0.03 moles of SO2 polymerization activator per mole of monomer and subjecting the polymer formed to sequential treat-ment with first a liquid oxidizing agent and second a reducing agent to obtain a white polymer product.
2. A method according to claim 1 wherein the liquid oxidizing agent is selected from the group consisting of hydrogen peroxide, potassium persulfate and sodium perborate.
3. A method according to claim 1 wherein the reducing agent is a solution of sodium metabisulfite.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US55475975A | 1975-03-03 | 1975-03-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1070893A true CA1070893A (en) | 1980-01-29 |
Family
ID=24214599
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA245,567A Expired CA1070893A (en) | 1975-03-03 | 1976-02-11 | Process for polymerization of 2-pyrrolidone and product produced |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS51111292A (en) |
| CA (1) | CA1070893A (en) |
| CH (1) | CH601380A5 (en) |
| DE (1) | DE2606268A1 (en) |
| FR (1) | FR2303038A1 (en) |
| GB (1) | GB1475062A (en) |
| IN (1) | IN145329B (en) |
| IT (1) | IT1053891B (en) |
| NL (1) | NL7602216A (en) |
-
1976
- 1976-02-11 CA CA245,567A patent/CA1070893A/en not_active Expired
- 1976-02-17 DE DE19762606268 patent/DE2606268A1/en not_active Withdrawn
- 1976-02-19 CH CH203576A patent/CH601380A5/xx not_active IP Right Cessation
- 1976-02-19 GB GB659676A patent/GB1475062A/en not_active Expired
- 1976-02-20 JP JP51017812A patent/JPS51111292A/en active Pending
- 1976-02-23 IT IT48235/76A patent/IT1053891B/en active
- 1976-03-03 NL NL7602216A patent/NL7602216A/en not_active Application Discontinuation
- 1976-03-03 FR FR7605990A patent/FR2303038A1/en active Granted
- 1976-04-02 IN IN582/CAL/76A patent/IN145329B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE2606268A1 (en) | 1976-09-16 |
| CH601380A5 (en) | 1978-07-14 |
| FR2303038B3 (en) | 1978-12-01 |
| IT1053891B (en) | 1981-10-10 |
| JPS51111292A (en) | 1976-10-01 |
| IN145329B (en) | 1978-09-23 |
| AU1161376A (en) | 1977-09-08 |
| NL7602216A (en) | 1976-09-07 |
| FR2303038A1 (en) | 1976-10-01 |
| GB1475062A (en) | 1977-06-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |