US3086046A - Cleavage of diacrylic acid to form acrylic acid - Google Patents

Cleavage of diacrylic acid to form acrylic acid Download PDF

Info

Publication number
US3086046A
US3086046A US3933A US393360A US3086046A US 3086046 A US3086046 A US 3086046A US 3933 A US3933 A US 3933A US 393360 A US393360 A US 393360A US 3086046 A US3086046 A US 3086046A
Authority
US
United States
Prior art keywords
acrylic acid
cleavage
acid
kilograms
vapors
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 - Lifetime
Application number
US3933A
Inventor
Kutepow Nikolaus Von
Doerfel Helmut
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.)
BASF SE
Original Assignee
BASF SE
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 BASF SE filed Critical BASF SE
Application granted granted Critical
Publication of US3086046A publication Critical patent/US3086046A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C57/00—Unsaturated compounds having carboxyl groups bound to acyclic carbon atoms
    • C07C57/02—Unsaturated compounds having carboxyl groups bound to acyclic carbon atoms with only carbon-to-carbon double bonds as unsaturation
    • C07C57/03—Monocarboxylic acids
    • C07C57/04—Acrylic acid; Methacrylic acid

Definitions

  • acrylic acid from acetylene, carbon monoxide and water in the presence of suitable catalysts, for example nickel bromide and copper iodide, at increased pressure and elevated temperature, various acrylic acid derivatives are obtained as byproducts in addition to the main product which is acrylic acid.
  • suitable catalysts for example nickel bromide and copper iodide
  • diacrylic acid there are formed polyacrylic acids having the structural features of diacrylic acid, polyacrylic acids connected by carbon-carbon linkages, hydracrylic acid and polyesters of hydracrylic acid. Since no use for the mixture of these acrylic acid derivatives is known, attempts have been made to split up these compounds into acrylic acid.
  • the acrylic acid derivatives formed as byproducts can be continuously split up into acrylic acid by vaporizing the acrylic acid derivatives at a pressure of between about 5 and 150, preferably and 100 mm. Hg absolute and leading the vapors under reduced pressure through a vessel heated to 350 to 650 0., preferably to 450 to 600 C.
  • tubes which have a large wall surface in relation to the reaction space. Tubes of stainless steel with an inside diameter of about to 30 limeters have proved suitable. Only relatively short periods are required for the thermal cleavage. The residence periods in the cleavage tubes are about 0.2 to
  • the speed of flow of the vapors may be between about 10 and 50 meters per second.
  • the walls of the vessel in which the cleavage is carried out (in gen eral these are stainless steel tubes) are heated to temperatures between 350 to 650 0., preferably between 450 and 600 C.
  • the vapors of the acrylic acid derivatives to be split up have temperatures between about 300 and 500 C.
  • a throughput of 13.5 kilograms of cleavage acrylic acid per day per liter of reaction space can be achieved in a tube of stainless steel having a plurality of bends, a diameter of 20 millimeters and a length of 10 meters with a wall temperature between 600 and 620 C. and a vapor temperature of about 380 C., a vapor speed of 30 meters per second and a residence period of 0.33 second.
  • the throughput is only 2.42 kilograms of cleavage acrylic acid per liter of reaction space per day.
  • the cleavage reaction takes place at the hot tube wall because under approximately identical conditions the cleavage outputs are proportional to the tube wall surface.
  • the acrylic acid derivatives to be split up which in general remain in the sump of the column in the distillation of the crude acrylic acid, are continuously vaporized in a vaporizer at heating temperatures of between and 270 C. and at pressures between 2 and 200 mm. Hg and led from the top of the vaporizer directly into the inlet of the cleavage tube. Turbulent-film Vaporizers, especially Sambay turbulent-film vaporizers, have proved suitable for the purpose. 'Upon leaving the cleavage tube the cleavage products .are cooled as quickly as possible to about 30 to 40 C. and condensed.
  • the process of the present invention it is possible to split up the distillation residues arising in the distillation of acrylic acid obtained catalytically from acetylene, carbon monoxide and water, to the extent of about 60 to 80% by weight into acrylic acid which can be worked up in known manner, possibly after distillation. It is surprising that at the relatively high temperature at which the cleavage of the acrylic acid derivatives is carried out, no formation of carbon black or blockage of the cleavage vessel occurs but the acrylic acid present in free form and in the form of low molecular products in the initial mixture can be substantially recovered.
  • Example 1 1,951 kilograms of crude acrylic acid distillation residue (consisting of 1,510 kilograms of diacry-lic acid, 164 kilograms of acrylic acid, 97 kilograms of hydracrylic acid and compounds not identified analytically) are evaporated in the course of 272 hours in a Sambay turbulentfilm vaporizer A (see the accompanying diagrammatic drawing) at a heating temperature of C. and a pressure of 30 to 60 mm. Hg to the extent of 42% by weight. From the top of the vaporizer, the vapors of the acrylic acid derivatives to be split up pass into a stainless steel tube B 20 mm. in diameter and 10 meters in length which is bent a plurality of times and of which the wall is heated to 600 to 620 C. The speed of the vapors, in the cleavage tube is 30 meters per second and the residence period of the vapors is 0.33 second.
  • the vapors leaving the tube B at a temperature of 380 C. are condensed in a water-cooled condenser C and in a subsequent cold trap D at 20 to 40 mm. Hg.
  • cleavage distillate of 824 kilograms consists of 617 kilograms of acrylic acid (74.8%), 159 kilograms of diacrylic acid (19.3%) and 48 kilograms of components not analytically identified. 45 kilograms of acrylic acid, 935 kilograms of diacrylic acid, 56 kilograms of hydracrylic acid and some unidentified components are contained in the non-vaporizable residue from the Sambay vaporizer (11,127 kilograms), and these can be again evaporated and split.
  • the above-mentioned analytical data show that 477 kilograms of acrylic acid have been produced by thermal gas-phase cleavage of diacrylic acid and hydracrylic acid.
  • the throughput is 1 3.5 kilograms of cleavage acrylic acid per liter of reaction space per day.
  • Example 2 In 20 hours, 482 kilograms of crude acrylic acid distillation residue (consisting of 79 kilograms of acrylic acid, 333 kilograms of diacrylic acid and components not identified analytically) are evaporated in a Sambay turbulent-film vaporizer A at a heating temperature of 240 C. and a pressure of 38 mm. Hg to the extent of 80% by weight.
  • the vapors of the acrylic acid derivatives to be split are led through an electrically heated tube B of stainless steel having a diameter of 50 mm. and a length of 30 meters.
  • the wall of the cleavage tube has a temperature of 478 C., and the vapors have a temperature of 416 C.
  • the mean vapor speed in the cleavage tube is 47 meters per second, the residence period of the vapors 0.64 second.
  • the vapors After leaving the cleavage tube, the vapors are condensed at 20 mm. Hg in a Water-cooled condenser C and in a trap D cooled with brine.
  • the cleavage distillate consists of 284 kilograms of acrylic acid (76.5%), 46.4 kilograms of diacrylic acid (12.5%) and 401 kilograms of compounds not identified analytically.
  • the nonvaporizable residue from the turbulent-film vaporizer (83 kilograms) there are contained 11.5 kilograms of acrylic acid, 53.5 kilograms of diacrylic acid or polyacrylic acids having the structural features of diacrylic acid, and some unidentified components.
  • Example 3 During operation for 18 hours, 473 kilograms of crude acrylic acid distillation residue containing 45.5 kilograms of acrylic acid, 400 kilograms of diacrylic acid and some components not identified analytically are evaporated in a Sambay turbulent-film vaporizer A at a heating temperature of 240 C. and a pressure of 44 mm. Hg to the extent of 83% by' weight.
  • the vapors of the acrylic acid derivatives to be split pass from the head of the vaporizer into an electrically heated stainless steel tube B of mm. diameter and 30 meters length.
  • the temperature of the tube Wall is 538 C. and the temperature of the vapors is 441 C.; the speed of the vapors is 48 meters per second and the residence period of the vapors in the cleavage tube is 0.62 second.
  • the vapors consisting mainly of acrylic acid, after leaving the cleavage tube, are condensed at 22 mm. Hg in a water-cooled condenser C and in a trap D cooled with brine. They contain, besides 306 kilograms of acrylic acid (79.5%), 35 kilograms of diacrylic acid (9.1%) and 44 kilograms of components not identified analytically.
  • the residue from the turbulent-film vaporizer is kilograms.
  • the yield of acrylic acid, with reference to acrylic acid distillation residue, is 65%.
  • a process for the production of acrylic acid by continuous cleavage of diacrylic acid which comprises: leading the vapors of said diacrylic acid at a pressure of between 5 and mm. Hg through a vessel heated to a temperature of about 350 to 650 C.
  • a process for the production of acrylic acid by continuous cleavage of diacrylic acid which comprises: vaporizing said diacrylic acid at a pressure of between 5 and 150 mm. Hg and a temperature of between 180 and 270 C. and leading the vapors at a pressure of between 5 and 150 mm. Hg through a vessel heated to a temperature of about 350 to 650 C.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Description

April 6, 1963 N. VON KUTEPOW ETAL 3,085,046
CLEAVAGE OF DIACRYL-IC. ACID TOIFORM ACRYLIC ACID Filed Jan. 21, 1960 INVENTORS: NIKOLAUS vow KUTEPOW HELMUT DOERFEL ATT'YS United States Patent 3,086,046 CLEAVAGE 0F DIACRYLIC ACID TO FORM ACRYLIC ACID Nikolaus vou Kutepow, Karlsruhe-Ruppurr, and Heimut Doerfel, Ludwigsllafen (Rhine), Germany, assignors to Badische Anilin- & Soda-Fabrik Aktiengesellschaft, Ludwigshafen (Rhine), Germany Filed Jan. 21, 1960, Ser. No. 3,933 Claims priority, application Germany Jan. 30, 1959 4 Claims. (Cl. 260-526) This invention relates to a process for the continuous cleavage of acrylic acid derivatives in the gas phase to form acrylic acid.
In the synthesis of acrylic acid from acetylene, carbon monoxide and water in the presence of suitable catalysts, for example nickel bromide and copper iodide, at increased pressure and elevated temperature, various acrylic acid derivatives are obtained as byproducts in addition to the main product which is acrylic acid. Besides diacrylic acid there are formed polyacrylic acids having the structural features of diacrylic acid, polyacrylic acids connected by carbon-carbon linkages, hydracrylic acid and polyesters of hydracrylic acid. Since no use for the mixture of these acrylic acid derivatives is known, attempts have been made to split up these compounds into acrylic acid.
It is known to cleave the said acrylic acid derivatives in the liquid phase at temperatures of 35 to 85 C. and at pressures of 10 to 100 mm. Hg absolute in the presence of acid catalysts, such as sulfuric acid, phosphoric acid, para-toluene-sulfonic acid and the like, to form acrylic acid. This cleavage in the liquid phase has considerable disadvantages, however, especially because it cannot be carired out continuously.
That fraction of the residue remaining in the cleavage vessel after distilling off the acrylic acid, which does not undergo cleavage and contains the catalyst from the acrylic acid synthesis and certain unidentified dark-colored resinous constituents, is turned in the course of the cleavage into such a viscous reaction mixture that a continuous Withdrawal of the non-cleavable fraction from the cleavage vessel becomes impossible for mechanical reasons. Nor can the reaction mixture be stirred. This leads to incrustation on the walls of the vessel in which the cleavage is carried out and the heat transfer from the vessel wall to the material to be split up is thereby worsened. Cleavage in the liquid phase must therefore be carried out discontinuously. After every batch, the reaction vessel must be cleaned mechanically and by boiling out with soda.
We have now found that in the catalytic production of acrylic acid from acetylene, carbon monoxide and water, the acrylic acid derivatives formed as byproducts can be continuously split up into acrylic acid by vaporizing the acrylic acid derivatives at a pressure of between about 5 and 150, preferably and 100 mm. Hg absolute and leading the vapors under reduced pressure through a vessel heated to 350 to 650 0., preferably to 450 to 600 C.
Surprisingly, when the vapors of acrylic acid derivatives are led through heated vessels no incrustation or formation of carbon black takes place on the walls. It is therefore possible to carry out the thermal cleavage of acrylic acid derivatives in the gas phase continuously.
As vessels in which the thermal cleavage takes place it is preferable to use tubes which have a large wall surface in relation to the reaction space. Tubes of stainless steel with an inside diameter of about to 30 limeters have proved suitable. Only relatively short periods are required for the thermal cleavage. The residence periods in the cleavage tubes are about 0.2 to
2 seconds. The speed of flow of the vapors may be between about 10 and 50 meters per second. The walls of the vessel in which the cleavage is carried out (in gen eral these are stainless steel tubes) are heated to temperatures between 350 to 650 0., preferably between 450 and 600 C. The vapors of the acrylic acid derivatives to be split up have temperatures between about 300 and 500 C.
For example a throughput of 13.5 kilograms of cleavage acrylic acid per day per liter of reaction space can be achieved in a tube of stainless steel having a plurality of bends, a diameter of 20 millimeters and a length of 10 meters with a wall temperature between 600 and 620 C. and a vapor temperature of about 380 C., a vapor speed of 30 meters per second and a residence period of 0.33 second. In a stainless steel tube having a diameter of 70 mm. and a length of 7 meters and with a tube wall temperature of about 580 C., with a steam temperature of about 460 C., a vapor speed of 5.6 meters per second and a residence period of 1 second, the throughput is only 2.42 kilograms of cleavage acrylic acid per liter of reaction space per day. The cleavage reaction takes place at the hot tube wall because under approximately identical conditions the cleavage outputs are proportional to the tube wall surface.
The acrylic acid derivatives to be split up, which in general remain in the sump of the column in the distillation of the crude acrylic acid, are continuously vaporized in a vaporizer at heating temperatures of between and 270 C. and at pressures between 2 and 200 mm. Hg and led from the top of the vaporizer directly into the inlet of the cleavage tube. Turbulent-film Vaporizers, especially Sambay turbulent-film vaporizers, have proved suitable for the purpose. 'Upon leaving the cleavage tube the cleavage products .are cooled as quickly as possible to about 30 to 40 C. and condensed.
According to the process of the present invention it is possible to split up the distillation residues arising in the distillation of acrylic acid obtained catalytically from acetylene, carbon monoxide and water, to the extent of about 60 to 80% by weight into acrylic acid which can be worked up in known manner, possibly after distillation. It is surprising that at the relatively high temperature at which the cleavage of the acrylic acid derivatives is carried out, no formation of carbon black or blockage of the cleavage vessel occurs but the acrylic acid present in free form and in the form of low molecular products in the initial mixture can be substantially recovered.
The following examples will further illustrate this invention but the invention is not restricted to these examples.
Example 1 1,951 kilograms of crude acrylic acid distillation residue (consisting of 1,510 kilograms of diacry-lic acid, 164 kilograms of acrylic acid, 97 kilograms of hydracrylic acid and compounds not identified analytically) are evaporated in the course of 272 hours in a Sambay turbulentfilm vaporizer A (see the accompanying diagrammatic drawing) at a heating temperature of C. and a pressure of 30 to 60 mm. Hg to the extent of 42% by weight. From the top of the vaporizer, the vapors of the acrylic acid derivatives to be split up pass into a stainless steel tube B 20 mm. in diameter and 10 meters in length which is bent a plurality of times and of which the wall is heated to 600 to 620 C. The speed of the vapors, in the cleavage tube is 30 meters per second and the residence period of the vapors is 0.33 second.
The vapors leaving the tube B at a temperature of 380 C. are condensed in a water-cooled condenser C and in a subsequent cold trap D at 20 to 40 mm. Hg.
aoeeoae The cleavage distillate of 824 kilograms consists of 617 kilograms of acrylic acid (74.8%), 159 kilograms of diacrylic acid (19.3%) and 48 kilograms of components not analytically identified. 45 kilograms of acrylic acid, 935 kilograms of diacrylic acid, 56 kilograms of hydracrylic acid and some unidentified components are contained in the non-vaporizable residue from the Sambay vaporizer (11,127 kilograms), and these can be again evaporated and split.
The above-mentioned analytical data show that 477 kilograms of acrylic acid have been produced by thermal gas-phase cleavage of diacrylic acid and hydracrylic acid. The throughput is 1 3.5 kilograms of cleavage acrylic acid per liter of reaction space per day.
Example 2 In 20 hours, 482 kilograms of crude acrylic acid distillation residue (consisting of 79 kilograms of acrylic acid, 333 kilograms of diacrylic acid and components not identified analytically) are evaporated in a Sambay turbulent-film vaporizer A at a heating temperature of 240 C. and a pressure of 38 mm. Hg to the extent of 80% by weight. The vapors of the acrylic acid derivatives to be split are led through an electrically heated tube B of stainless steel having a diameter of 50 mm. and a length of 30 meters. The wall of the cleavage tube has a temperature of 478 C., and the vapors have a temperature of 416 C. The mean vapor speed in the cleavage tube is 47 meters per second, the residence period of the vapors 0.64 second.
After leaving the cleavage tube, the vapors are condensed at 20 mm. Hg in a Water-cooled condenser C and in a trap D cooled with brine. The cleavage distillate consists of 284 kilograms of acrylic acid (76.5%), 46.4 kilograms of diacrylic acid (12.5%) and 401 kilograms of compounds not identified analytically. In the nonvaporizable residue from the turbulent-film vaporizer (83 kilograms) there are contained 11.5 kilograms of acrylic acid, 53.5 kilograms of diacrylic acid or polyacrylic acids having the structural features of diacrylic acid, and some unidentified components.
Example 3 During operation for 18 hours, 473 kilograms of crude acrylic acid distillation residue containing 45.5 kilograms of acrylic acid, 400 kilograms of diacrylic acid and some components not identified analytically are evaporated in a Sambay turbulent-film vaporizer A at a heating temperature of 240 C. and a pressure of 44 mm. Hg to the extent of 83% by' weight. The vapors of the acrylic acid derivatives to be split pass from the head of the vaporizer into an electrically heated stainless steel tube B of mm. diameter and 30 meters length. The temperature of the tube Wall is 538 C. and the temperature of the vapors is 441 C.; the speed of the vapors is 48 meters per second and the residence period of the vapors in the cleavage tube is 0.62 second.
The vapors consisting mainly of acrylic acid, after leaving the cleavage tube, are condensed at 22 mm. Hg in a water-cooled condenser C and in a trap D cooled with brine. They contain, besides 306 kilograms of acrylic acid (79.5%), 35 kilograms of diacrylic acid (9.1%) and 44 kilograms of components not identified analytically. The residue from the turbulent-film vaporizer is kilograms. The yield of acrylic acid, with reference to acrylic acid distillation residue, is 65%.
What we claim is:
1. A process for the production of acrylic acid by continuous cleavage of diacrylic acid, which comprises: leading the vapors of said diacrylic acid at a pressure of between 5 and mm. Hg through a vessel heated to a temperature of about 350 to 650 C.
2. A process for the production of acrylic acid by continuous cleavage of diacrylic acid, which comprises: vaporizing said diacrylic acid at a pressure of between 5 and 150 mm. Hg and a temperature of between 180 and 270 C. and leading the vapors at a pressure of between 5 and 150 mm. Hg through a vessel heated to a temperature of about 350 to 650 C.
3. A process as claimed in claim 2 in which the vapors have a residence period in said vessel of about 0.5 to 2 seconds.
4. A process as claimed in claim 2 in which the speed of flow of the vapors in said vessel is between about 10 and 50 meters per second.
References Cited in the file of this patent UNITED STATES PATENTS 2,435,510 Redmon Oct. 18, 1949

Claims (1)

1. A PROCESS FOR PRODUCTION OF ACRYLIC ACID BY CONTINUOUS CLEAVAGE OF DIACRYLIC ACID, WHICH COMPRISES: LEADING THE VAPORS OF SAID DIACRYLIC ACID AT A PRESSURE OF BETWEEN 5 AND 150 MM. HG THROUGH A VESSEL HEATED TO A TEMPERATURE OF ABOUT 350* TO 650* C.
US3933A 1959-01-30 1960-01-21 Cleavage of diacrylic acid to form acrylic acid Expired - Lifetime US3086046A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE3086046X 1959-01-30

Publications (1)

Publication Number Publication Date
US3086046A true US3086046A (en) 1963-04-16

Family

ID=8086287

Family Applications (1)

Application Number Title Priority Date Filing Date
US3933A Expired - Lifetime US3086046A (en) 1959-01-30 1960-01-21 Cleavage of diacrylic acid to form acrylic acid

Country Status (1)

Country Link
US (1) US3086046A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3954854A (en) * 1974-02-15 1976-05-04 Hoechst Aktiengesellschaft Recovery of monomeric acrylic acid from residues originating from processed crude acrylic acid
DE2901783A1 (en) * 1978-01-19 1979-08-02 Nippon Catalytic Chem Ind PROCESS FOR RECOVERY OF ACRYLIC ACID
FR2727964A1 (en) * 1994-12-12 1996-06-14 Atochem Elf Sa PROCESS FOR RECOVERING THE LIGHT NOBLE PRODUCTS CONTAINED IN THE DISTILLATION RESIDUES FROM THE MANUFACTURING PROCESSES OF ACRYLIC ACID AND ITS ESTERS
US6498272B1 (en) 1999-03-06 2002-12-24 Basf Aktiengesellschaft Method for producing acrylic acid
US20040210085A1 (en) * 2001-11-22 2004-10-21 Shuhei Yada Method of recovering polymerization inhibitor and method of producing acrylic acid
US20070280866A1 (en) * 2004-02-19 2007-12-06 Torsten Balduf Cleaving Of Oligomeric (Meth) Acrylic Acid In A Liquid Phase Under Pressure

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2485510A (en) * 1946-02-13 1949-10-18 American Cyanamid Co Preparation of acrylic acid and esters thereof

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2485510A (en) * 1946-02-13 1949-10-18 American Cyanamid Co Preparation of acrylic acid and esters thereof

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3954854A (en) * 1974-02-15 1976-05-04 Hoechst Aktiengesellschaft Recovery of monomeric acrylic acid from residues originating from processed crude acrylic acid
DE2901783A1 (en) * 1978-01-19 1979-08-02 Nippon Catalytic Chem Ind PROCESS FOR RECOVERY OF ACRYLIC ACID
FR2415092A1 (en) * 1978-01-19 1979-08-17 Nippon Catalytic Chem Ind PROCEDURE FOR RECOVERING THE OLIGOMERS OF ACRYLIC ACID OBTAINED IN THE PREPARATION OF THIS COMPOUND BY SIMULTANEOUSLY RECOVERING THE HYDROQUINONE USED AS A POLYMERIZATION INHIBITOR
FR2727964A1 (en) * 1994-12-12 1996-06-14 Atochem Elf Sa PROCESS FOR RECOVERING THE LIGHT NOBLE PRODUCTS CONTAINED IN THE DISTILLATION RESIDUES FROM THE MANUFACTURING PROCESSES OF ACRYLIC ACID AND ITS ESTERS
EP0717031A1 (en) * 1994-12-12 1996-06-19 Elf Atochem S.A. Process for recovering the light noble products contained in the distillation residues from the processes of production of acrylic acid and its esters
JPH08225486A (en) * 1994-12-12 1996-09-03 Elf Atochem Sa Method of recovering low-boiling value from distillation residue from production process for acrylic acid and its ester
JP2663413B2 (en) 1994-12-12 1997-10-15 エルフ アトケム ソシエテ アノニム Method for recovering light valuables present in distillation bottoms from the production process of acrylic acid and its esters
US5734075A (en) * 1994-12-12 1998-03-31 Elf Atochem S.A. Process for recovery of the light noble products present in the distillation residues from the processes for the manufacture of acrylic acid and of its esters
CN1092635C (en) * 1994-12-12 2002-10-16 埃勒夫阿托化学有限公司 Recovery of noble light products in distillation residues obtd. during manufacture of acrylic acid or its ester
US6498272B1 (en) 1999-03-06 2002-12-24 Basf Aktiengesellschaft Method for producing acrylic acid
US20040210085A1 (en) * 2001-11-22 2004-10-21 Shuhei Yada Method of recovering polymerization inhibitor and method of producing acrylic acid
US7041849B2 (en) * 2001-11-22 2006-05-09 Mitsubishi Chemical Corporation Method of recovering polymerization inhibitor and method of producing acrylic acid
US20070280866A1 (en) * 2004-02-19 2007-12-06 Torsten Balduf Cleaving Of Oligomeric (Meth) Acrylic Acid In A Liquid Phase Under Pressure

Similar Documents

Publication Publication Date Title
US2021698A (en) Vinyl ester
WO1994018146A1 (en) Process for the manufacture of 2,2,4,4-tetramethylcyclobutanediol
US4032563A (en) Process for the recovery of high purity diesters of terephthalic or isophthalic acids
US3086046A (en) Cleavage of diacrylic acid to form acrylic acid
US2340490A (en) Dehydration of maleic acid
US1400195A (en) Process of making methyl formate
US2026985A (en) Process for the manufacture of aliphatic acid anhydrides
US1898687A (en) Acetylation process
US3227743A (en) Production of dimethyl terephthalate
US2932665A (en) Preparation of nu, nu-diethyltoluamides
US4150243A (en) Process for the dealkylation of tert.-alkyl substituted phenols
US3300531A (en) Process for preparing dimethylacetamide
US2150158A (en) Method for the manufacture of propionic aldehyde
Church et al. Methyl Methacrylate from methallyl alcohol
US3972951A (en) Process for the formation of 2,6-diphenyl-phenol
US2454047A (en) Conversion of alicyclic aldehydes
NL7906169A (en) PROCESS FOR THE PREPARATION OF ISOPROPENYLPHENOL.
US2442716A (en) Production of alkyl acrylates
US4968834A (en) Recovery of acrylic acid and/or ethyl acrylate from black acid
US3719718A (en) Process for the production of cyclopentadiene from dicyclopentadiene
EP0074162B1 (en) Process for producing p-cresol
US2816134A (en) Preparation of chlorinated aromatic carboxylic acid esters
US3663613A (en) Separation of organic acid products and water from catalysts after synthesis by reduced pressure distillation
US2258947A (en) Production of itaconic and citraconic anhydrides
US2007144A (en) Method of making ethylidene chloride