EP0617729A1 - Styrene polymerization inhibitor - Google Patents
Styrene polymerization inhibitorInfo
- Publication number
- EP0617729A1 EP0617729A1 EP89905964A EP89905964A EP0617729A1 EP 0617729 A1 EP0617729 A1 EP 0617729A1 EP 89905964 A EP89905964 A EP 89905964A EP 89905964 A EP89905964 A EP 89905964A EP 0617729 A1 EP0617729 A1 EP 0617729A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- polymerization inhibitor
- styrene
- pnp
- monomer
- polymerization
- 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.)
- Withdrawn
Links
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 title claims abstract description 40
- 239000003112 inhibitor Substances 0.000 title claims abstract description 31
- 238000006116 polymerization reaction Methods 0.000 title claims abstract description 25
- JSTCPNFNKICNNO-UHFFFAOYSA-N 4-nitrosophenol Chemical compound OC1=CC=C(N=O)C=C1 JSTCPNFNKICNNO-UHFFFAOYSA-N 0.000 claims abstract description 33
- 239000000178 monomer Substances 0.000 claims abstract description 15
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000002904 solvent Substances 0.000 claims abstract description 11
- 238000000034 method Methods 0.000 claims abstract description 8
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 6
- MYRTYDVEIRVNKP-UHFFFAOYSA-N 1,2-Divinylbenzene Chemical compound C=CC1=CC=CC=C1C=C MYRTYDVEIRVNKP-UHFFFAOYSA-N 0.000 claims description 4
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 claims description 4
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 4
- RRHGJUQNOFWUDK-UHFFFAOYSA-N Isoprene Chemical compound CC(=C)C=C RRHGJUQNOFWUDK-UHFFFAOYSA-N 0.000 claims description 4
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 4
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 2
- SBYMUDUGTIKLCR-UHFFFAOYSA-N 2-chloroethenylbenzene Chemical compound ClC=CC1=CC=CC=C1 SBYMUDUGTIKLCR-UHFFFAOYSA-N 0.000 claims description 2
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 2
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 claims description 2
- 150000002989 phenols Chemical class 0.000 claims description 2
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 2
- 125000003011 styrenyl group Chemical group [H]\C(*)=C(/[H])C1=C([H])C([H])=C([H])C([H])=C1[H] 0.000 claims 1
- 230000002401 inhibitory effect Effects 0.000 abstract description 3
- 239000000203 mixture Substances 0.000 abstract description 3
- KSHJAFFDLKPUMT-UHFFFAOYSA-N dinitro-ortho-cresol Chemical compound CC1=C(O)C=C([N+]([O-])=O)C=C1[N+]([O-])=O KSHJAFFDLKPUMT-UHFFFAOYSA-N 0.000 description 17
- 229920000642 polymer Polymers 0.000 description 13
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 12
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 description 10
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 3
- 239000005977 Ethylene Substances 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000004793 Polystyrene Substances 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 231100001231 less toxic Toxicity 0.000 description 3
- 229920002223 polystyrene Polymers 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 231100000331 toxic Toxicity 0.000 description 2
- 230000002588 toxic effect Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- JIGUICYYOYEXFS-UHFFFAOYSA-N 3-tert-butylbenzene-1,2-diol Chemical compound CC(C)(C)C1=CC=CC(O)=C1O JIGUICYYOYEXFS-UHFFFAOYSA-N 0.000 description 1
- XESZUVZBAMCAEJ-UHFFFAOYSA-N 4-tert-butylcatechol Chemical compound CC(C)(C)C1=CC=C(O)C(O)=C1 XESZUVZBAMCAEJ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000004676 acrylonitrile butadiene styrene Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000013000 chemical inhibitor Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 239000006184 cosolvent Substances 0.000 description 1
- -1 dinitrσphenols Chemical compound 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 229920002959 polymer blend Polymers 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
- C08F212/02—Monomers containing only one unsaturated aliphatic radical
- C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
- C08F212/06—Hydrocarbons
- C08F212/08—Styrene
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/38—Separation; Purification; Stabilisation; Use of additives
- C07C17/42—Use of additives, e.g. for stabilisation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/20—Use of additives, e.g. for stabilisation
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K15/00—Anti-oxidant compositions; Compositions inhibiting chemical change
- C09K15/04—Anti-oxidant compositions; Compositions inhibiting chemical change containing organic compounds
- C09K15/28—Anti-oxidant compositions; Compositions inhibiting chemical change containing organic compounds containing nitrogen, oxygen and sulfur
Definitions
- the field of this invention is in the inhibition of the polymerization of styrene during the manufacture of the monomer.
- inhibitors such as sulfur, dinitr ⁇ phenols, and p-tert-butylcatechol have been used in the past as inhibitors.
- the chemistry of styrene is well-known as one of the earliest of the modern thermoplastics and still one of the largest in volume in production, including many copolymers and polymer blends, such as SBR rubber and acrylonitrile-butadiene-styrene (ABS) .
- Paranitrosophenol (PNP) and dinitro-orthocresol (DNOC) are currently known polymerization inhibitors, but PNP is a solid and DNOC is highly toxic, which has limited their utility.
- a solution of PNP in the solvent n-methylpyrollidone (NMP) is a highly effective system for inhibiting the polymerization of styrene and its analogs and for general use in inhibiting polymerization of vinyl and other addition polymerizable monomers during their production from the various feedstocks.
- PNP in solution in NMP is miscible with both the feedstocks and the monomers produced within certain limits.
- DESCRIPTION OF THE PREFERRED EMBODIMENT A solution of paranitrosophenol in the solvent n-methylpyrollidone is used as a polymerization inhibitor in the production of styrene monomer.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Water Supply & Treatment (AREA)
- Analytical Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Materials Engineering (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Polymerisation Methods In General (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Anti-Oxidant Or Stabilizer Compositions (AREA)
Abstract
Compositions utiles pour inhiber la polymérisation de monomères, comprenant un solvant miscible dans la charge de départ destinée au monomère, et miscible dans le monomère, ainsi qu'un inhibiteur de polymérisation. On a mis au point des procédés de production de styrène, consistant à utiliser une composition de para-nitrosophénol dans n-méthyle pyrolidone, afin d'inhiber la polymérisation.Compositions useful for inhibiting the polymerization of monomers, comprising a solvent miscible in the starting charge intended for the monomer, and miscible in the monomer, as well as a polymerization inhibitor. Methods for producing styrene have been developed which include the use of a para-nitrosophenol composition in n-methyl pyrolidone to inhibit polymerization.
Description
STYRENE POLYMERIZATION INHIBITOR
BACKGROUND OF THE INVENTION
The field of this invention is in the inhibition of the polymerization of styrene during the manufacture of the monomer.
Styrene production and chemistry are treated in the Kirk-Othmer Encyclopedia of Chemical Technology, John Wiley and Sons, New York 1982 (Vol. 21) and numerous other publications.
During the production of styrene, inhibitors such as sulfur, dinitrσphenols, and p-tert-butylcatechol have been used in the past as inhibitors. The chemistry of styrene is well-known as one of the earliest of the modern thermoplastics and still one of the largest in volume in production, including many copolymers and polymer blends, such as SBR rubber and acrylonitrile-butadiene-styrene (ABS) . Paranitrosophenol (PNP) and dinitro-orthocresol (DNOC) are currently known polymerization inhibitors, but PNP is a solid and DNOC is highly toxic, which has limited their utility.
SUMMARY OF THE INVENTION A solution of PNP in the solvent n-methylpyrollidone (NMP) is a highly effective system for inhibiting the polymerization of styrene and its analogs and for general use in inhibiting polymerization of vinyl and other addition polymerizable monomers during their production from the various feedstocks. PNP in solution in NMP is miscible with both the feedstocks and the monomers produced within certain limits.
DESCRIPTION OF THE PREFERRED EMBODIMENT A solution of paranitrosophenol in the solvent n-methylpyrollidone is used as a polymerization inhibitor in the production of styrene monomer. Paranitrosophenol is a well known polymerization inhibitor, but it is a solid not soluble in either ethylbenzene or ethylene, which are the usual feed stocks to the styrene process. However, we have found that, by using sufficient quantities of n-methylpyrollidone as a co-solvent, the solubility of the PNP can be increased to a point where it is a commercially viable inhibitor. Hence, both components of the product, the PNP and the solvent, are vital to commercial success.
We have found other solvents which may be used, in general these are aprotic very powerful solvents such as dimethyl formamide, tetrahydrofuran, dimethyl sulfoxide and the like, however, none has been as effective in all ways as NMP because of vapor pressures, corrosiveness, or other associated difficulties.
Styrene monomer is made from two basic building blocks, benzene and ethylene. Benzene and ethylene are alkylated using an aluminum based catalyst to form ethylbenzene. Ethylbenzene is then dehydrogenated, removing two hydrogen atoms from the ethyl group attached to the benzene ring, by passing it over a metal-oxide catalyst, usually iron oxide, with steam. The result is a mixture of styrene, ethylbenzene, benzene, and toluene. Polystyrene is also a byproduct because styrene is very reactive and styrene molecules will readily form polystyrene if given a chance, though operating conditions in the process are set to minimize this reaction. The styrene conversion rate is about 60% and the yield is about 90%. An accumulator is then used to take out water, then sequential distillation separates the ethylbenzene, benzene, and toluene from the pure styrene monomer. Divinylbenzene, chlorostyrene, butadiene, isoprene, acrylic acid, methacrylic acid, and vinyl chloride monomers can also be inhibited by this system.
Too much polystyrene will cause fouling of the equipment and result in an inefficient process. It is standard practice throughout the styrene industry to add a chemical inhibitor of some kind to help control polymerization. Dinitro-orthocresol works very well, but is extremely toxic. The general trend in the styrene industry is to find alternative inhibitors to DNOC, and that is precisely why our invention was developed.
The most widely used polymerization inhibitor in the industry today is DNOC although analogs of this compound are also sometimes used under the same name. The problem with the use of DNOC and its analogs is extreme toxicity. All data are not yet available, however, preliminary studies indicate that PNP is some 20 times less toxic. PNP was developed as a less toxic replacement for DNOC and this has proven to be a strong impetus for change of inhibitors in the marketplace.
The general system may be used with a large number of monomers in which polymerization inhibitors, in particularly substituted phenolic compounds, are of low solubility. In this connection it must be pointed out that no materials are completely insoluble in solvents, but only that their solubilities are so low as to be of no utility in that particular application under the normal process parameters involved.
In addition to being less toxic than DNOC, PNP has proven to be a more effective polymerization inhibitor on a weight for weight basis. Some results from reflux tests are as follows:
INHIBITOR PERCENT POLYMER
DNOC at 100 ppm 0.858
PNP at 100 ppm 0.0605
DNOC at 100 ppm + Na 2.452
PNP at 100 ppm + Na 0.0451
PNP at 50 ppm 0.240
PNP at 25 ppm 0.981
A sample of the monomer is washed with NaOH and water to remove any phenolic inhibitors, such as tert-butylcatechol, placed in distillation flask under nitrogen and distilled until polymer starts to form. The polymer is precipitated out of solution with methanol, dried and weighed. The above data shows that PNP is far more effective at equal dosage and almost as effective at one-fourth the dosage of DNOC and field testing has shown even greater effectiveness.
A recent trial at the sytrene unit in a commerical plant showed the PNP/NMP solution to be about 10 times more effective than DNOC in polymer reduction at one-fifth the dosage. The table below shows dosage in ppm of the actives in both DNOC and PNP versus resulting polymer levels in ppm. The study was done on two different stops in the styrene process (the Recycle Column and the Continuous Column). Mean polymer levels in the Recycle Column are 4,000 ppm with 500 ppm of DNOC inhibitor actives. Mean polymer levels in the Recycle Column are 455 ppm with only 125 ppm of PNP actives, hence, 10 times more effectiveness with one-fifth the dosage.
Fig. 1 illustrates polymer levels in the Recycle Column during the course of the trial. There is a dramatic drop in the polymer level after the start of feeding PNP.
RECYCLE COLUMN
Inhibitor Rate Dosage Polymer Polymer Range
DNOC 465 ml/min. 500 ppm 4, ,000 ppm 3,500-5000 ppm
PNP 80 100 725 595-850
PNP 100 125 455 400-510
PNP 130-135 160-170 415 310-515
PNP 170 210 390 240-535
CONTINUOUS COLUMN
Inhibitor Rate Polymer Polymer Range
DNOC 465 ml/min 46,000 ppm 39,000-55,OOOppm
PNP 80 9,700 8,330-11,050
PNP 100 7,550 6,660-8,435
PNP 130- 135 9,730 8,150-11,300
PNP 170 7,750 5,860-9,640
Claims
1. A polymerization inhibitor system for monomers comprising a solution of a polymerization inhibitor in a solvent which is miscible with the feedstock for the monomer and the monomer.
2. The polymerization inhibitor system of claim 1 wherein the polymeri¬ zation inhibitor comprises a substituted phenolic compound.
3. The polymerization inhibitor system of claim 1 wherein the polymeri¬ zation inhibitor comprises paranitrosophenol.
4. The polymerization inhibitor system of claim 1 in which the solvent is selected from the group of solvents consisting of n-methyl pyrollidone, dimethyl formamide, tetrahydrofuran and dimethyl sulfoxide.
5. The polymerization inhibitor system of claim 1 wherein the solvent is n-methyl pyrollidone.
6. The polymerization inhibitor system of claim 1 wherein from 25 to 210 parts of paranitrosophenol are used to 1 million parts of monomer.
7. The polymerization inhibitor system of claim 1 wherein the monomers are selected from the group consisting of styrene, divinyl benzene, chlorostyrene, butadiene, isoprene, vinyl chloride, acrylic acid, and methacrylic acid.
8. The polymerization inhibitor system of claim 1 wherein the monomer is styrene.
9. The process of producing styrene comprising the use of a solution of paranitrosophenol in n-methyl pyrollidone as a polymerization inhibitor during said process.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US1989/001573 WO1990012072A1 (en) | 1989-04-13 | 1989-04-13 | Styrene polymerization inhibitor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0617729A4 EP0617729A4 (en) | 1991-11-22 |
| EP0617729A1 true EP0617729A1 (en) | 1994-10-05 |
Family
ID=22214940
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP89905964A Withdrawn EP0617729A1 (en) | 1989-04-13 | 1989-04-13 | Styrene polymerization inhibitor |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0617729A1 (en) |
| JP (1) | JPH04502925A (en) |
| KR (1) | KR900016283A (en) |
| WO (1) | WO1990012072A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2277104C1 (en) * | 2004-12-29 | 2006-05-27 | Институт проблем химической физики РАН (ИПХФ РАН) | Free radical styrene polymerization process and "dormant" inhibitors for this process |
| US8865019B2 (en) | 2011-05-03 | 2014-10-21 | King Fahd University Of Petroleum And Minerals | Method of inhibiting free radical polymerization of styrene |
| JP2020111533A (en) * | 2019-01-10 | 2020-07-27 | 栗田工業株式会社 | Method for inhibiting polymerization of unsaturated aromatic monomer |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2225471A (en) * | 1937-12-24 | 1940-12-17 | Int Standard Electric Corp | Stabilization of styrene |
| US2867672A (en) * | 1955-08-29 | 1959-01-06 | Shell Dev | Method of minimizing styrene polymerization during storage |
| US2900421A (en) * | 1957-02-06 | 1959-08-18 | Morris S Kharasch | Inhibiting polymerization |
| US3426063A (en) * | 1964-09-10 | 1969-02-04 | Copolymer Rubber & Chem Corp | Inhibiting thermal polymerization and the growth of popcorn polymer |
| GB1064845A (en) * | 1966-03-10 | 1967-04-12 | Ferenc Tudos | Inhibiting polymerisation |
| US4237326A (en) * | 1979-05-30 | 1980-12-02 | Mitsubishi Petrochemical Company Limited | Method of inhibiting polymerization of styrene |
| JPS5630409A (en) * | 1979-08-20 | 1981-03-27 | Mitsubishi Petrochem Co Ltd | Method of feeding polymerization inhibitor |
| US4291054A (en) * | 1979-12-10 | 1981-09-22 | E. I. Du Pont De Nemours And Company | Insecticidal carbamoyl sulfides |
| US4434307A (en) * | 1982-12-27 | 1984-02-28 | Atlantic Richfield Company | Inhibiting polymerization of vinyl aromatic monomers |
| US4654451A (en) * | 1985-12-27 | 1987-03-31 | Atlantic Richfield Company | Inhibiting polymerization of vinyl aromatic monomers |
-
1989
- 1989-04-13 EP EP89905964A patent/EP0617729A1/en not_active Withdrawn
- 1989-04-13 WO PCT/US1989/001573 patent/WO1990012072A1/en not_active Application Discontinuation
- 1989-04-13 JP JP1505844A patent/JPH04502925A/en active Pending
- 1989-08-22 KR KR1019890011952A patent/KR900016283A/en not_active Withdrawn
Non-Patent Citations (2)
| Title |
|---|
| No further relevant documents have been disclosed. * |
| See also references of WO9012072A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0617729A4 (en) | 1991-11-22 |
| JPH04502925A (en) | 1992-05-28 |
| WO1990012072A1 (en) | 1990-10-18 |
| KR900016283A (en) | 1990-11-13 |
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Legal Events
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| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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| 17P | Request for examination filed |
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| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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| 18D | Application deemed to be withdrawn |
Effective date: 19960917 |