US2408177A - Improved process for the manufacture of methyl acrylate by the thermal decomposition of methyl alpha-acetoxypropionate - Google Patents
Improved process for the manufacture of methyl acrylate by the thermal decomposition of methyl alpha-acetoxypropionate Download PDFInfo
- Publication number
- US2408177A US2408177A US485618A US48561843A US2408177A US 2408177 A US2408177 A US 2408177A US 485618 A US485618 A US 485618A US 48561843 A US48561843 A US 48561843A US 2408177 A US2408177 A US 2408177A
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- Prior art keywords
- methyl
- acetoxypropionate
- manufacture
- methyl acrylate
- thermal decomposition
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
- C07C67/317—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by splitting-off hydrogen or functional groups; by hydrogenolysis of functional groups
- C07C67/327—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by splitting-off hydrogen or functional groups; by hydrogenolysis of functional groups by elimination of functional groups containing oxygen only in singly bound form
Definitions
- Our invention relates to the manufacture of unsaturated organic compounds and more particularly to the manufacture of acrylic esters by lysis generally yield the carboxylic acid and an unsaturated compound (Pelt and Wibaut, Rec.
- An object of our invention is to provide a commercial process for manufacturing unsaturated compounds, suchas acrylic esters, by passing certain esters of carboxylic acids through a hot tube or chamber.
- a further object is to provide improved conditions for pyrolysis which will increase the rate of conversion, increase the capacity of a pyrolysis unit of any given size, and decrease production costs and capital investment.
- esters of carboxylic acids can be transformed into unsaturated compounds by pyrolysis under pressures much higher than atmospheric pressure and that certain lactic acid derivatives can be converted into acrylic esters by pyrolysis of lactic acid derivatives under increased pressures.
- methyl alpha-acetoirypropionate which is prepared conveniently by acetylating the methyl ester of lactic acid, can be pyrolyzed satisfactorily at high pressures and that methyl acrylate is produced in good yield by this operation.
- the pyrolysis chamber may be empty or may contain packing materials such as quartz chips, Raschig'rings, lumps of coke, metal shavings, and so forth. Vapors of the carboXylic acid esters may be passed in at the bottom of the chamher and out at the top, or in at the top and out at the bottom, or if desired, the pyrolysis tube may be mounted in a horizontal position.
- the reagent methyl alpha-acetoxypropionate
- the reagent was allowed to flow by gravity from a calibrated cylinder into a constant-feed pump capable of operating under high pressures.
- the reagent was pumped under pressure into heated stainless-steel tubing inside diameter which was heated over a length of approximately 12 feet. The temperature was essentially uniform over a considerable length of the heated 12-foot section, although some of the forward end of the tubing served as a preheater.
- the vapors passed through a cooled condenser and into a high-pressure receiver. Gases were released through a throttling valve from the top of this receiver at such a rate that the desired pressure was maintained in the system-
- the liquid products were collected at the bottom of the receiver -by manipulation of a suitable Valve.
- Example I Methyl alpha-acetoxypropionate (315.5 grams) was pumped into the pyrolysis chamber at the rate of 1.12 moles per hour. The reaction temperature and pressure were 550 C. and 45 pounds per square inch, respectively. The liquid products were 85.4 percent of the charge. High conversions into methyl acrylate and acetic acid were obtained.
- Example I Methyl alpha-acetoxypropionate (858 grams) was pumped at pounds per square inch into the pyrolysis chamber at 550 C. The rate of pumping was 3.18 moles per hour. High conversions into methyl acrylate and acetic acid w re obtained.
- Example III Methyl alpha-acetoxypropionate (1580 grams) was pumped at 900 pounds per square inch into the pyrolysis chamber at 488 C. at a pumping rate of 23 moles per hour. The reagent was satisfactorily converted into methyl acrylate and acetic acid.
Description
Patented Sept. 24, 1946 IMPROVED PROCESS FOR THE MANUFAC- TURE OF METHYL ACRYLATE BY THE THERMAL DECOMPOSITION OF METHYL ALPHA-ACETOXYPROPIONATE William P. Ratchford, Willow Grove, and Charles r -H. Fisher, Abington, Pa., assignors to Claude R. Wickard, as Secretary of Agriculture of the United States of America, and his successors in No Drawing. Application May 4, 1943, Serial No. 485,618
1 Claim.
(Granted under the act of March 3, 1883, as amended April 30, 1928; 3'70 0. G. 757) This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described, if patented, may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment to us of any royalty thereon.
Our invention relates to the manufacture of unsaturated organic compounds and more particularly to the manufacture of acrylic esters by lysis generally yield the carboxylic acid and an unsaturated compound (Pelt and Wibaut, Rec.
trav. chem. 60, 55-64 (1941)) Hurd, Pyrolysis f Carbon Compounds, Reinhold Publishing Corp., New York city (1929). 7
An object of our invention is to provide a commercial process for manufacturing unsaturated compounds, suchas acrylic esters, by passing certain esters of carboxylic acids through a hot tube or chamber.
A further object is to provide improved conditions for pyrolysis which will increase the rate of conversion, increase the capacity of a pyrolysis unit of any given size, and decrease production costs and capital investment.
Other objects of our invention will be apparent from the following description.
We have found that esters of carboxylic acids can be transformed into unsaturated compounds by pyrolysis under pressures much higher than atmospheric pressure and that certain lactic acid derivatives can be converted into acrylic esters by pyrolysis of lactic acid derivatives under increased pressures. Moreover, we have found that methyl alpha-acetoirypropionate, which is prepared conveniently by acetylating the methyl ester of lactic acid, can be pyrolyzed satisfactorily at high pressures and that methyl acrylate is produced in good yield by this operation. We have also found that the pyrolysis of mixtures of methyl lactate and acetic anhydride under superatmospheric pressures yields methyl acrylate.
Further, we have found that the throughput of any given pyrolysis unit, and hence its capacthe pyrolysis under pressure. In addition, the
use of superatmospheric pressures as herein described hasthe following advantages over operation at essentially atmospheric pressure: (1) Better heat transfer is afforded, and (2) the boiling points of the products are raised and hence condensation of the products is facilitated.
The pyrolysis chamber, may be empty or may contain packing materials such as quartz chips, Raschig'rings, lumps of coke, metal shavings, and so forth. Vapors of the carboXylic acid esters may be passed in at the bottom of the chamher and out at the top, or in at the top and out at the bottom, or if desired, the pyrolysis tube may be mounted in a horizontal position.
In the examples set forth below, illustrating our invention, the reagent, methyl alpha-acetoxypropionate, was allowed to flow by gravity from a calibrated cylinder into a constant-feed pump capable of operating under high pressures. The reagent was pumped under pressure into heated stainless-steel tubing inside diameter which was heated over a length of approximately 12 feet. The temperature was essentially uniform over a considerable length of the heated 12-foot section, although some of the forward end of the tubing served as a preheater. After passing through the heated reaction zone, the vapors passed through a cooled condenser and into a high-pressure receiver. Gases were released through a throttling valve from the top of this receiver at such a rate that the desired pressure was maintained in the system- The liquid products were collected at the bottom of the receiver -by manipulation of a suitable Valve.
Example I Methyl alpha-acetoxypropionate (315.5 grams) was pumped into the pyrolysis chamber at the rate of 1.12 moles per hour. The reaction temperature and pressure were 550 C. and 45 pounds per square inch, respectively. The liquid products were 85.4 percent of the charge. High conversions into methyl acrylate and acetic acid were obtained.
Example I 1 Methyl alpha-acetoxypropionate (858 grams) was pumped at pounds per square inch into the pyrolysis chamber at 550 C. The rate of pumping was 3.18 moles per hour. High conversions into methyl acrylate and acetic acid w re obtained.
Example III Methyl alpha-acetoxypropionate (1580 grams) was pumped at 900 pounds per square inch into the pyrolysis chamber at 488 C. at a pumping rate of 23 moles per hour. The reagent was satisfactorily converted into methyl acrylate and acetic acid.
Our invention is not limited to the examples given above, but is applicable generally to the 10
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US485618A US2408177A (en) | 1943-05-04 | 1943-05-04 | Improved process for the manufacture of methyl acrylate by the thermal decomposition of methyl alpha-acetoxypropionate |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US485618A US2408177A (en) | 1943-05-04 | 1943-05-04 | Improved process for the manufacture of methyl acrylate by the thermal decomposition of methyl alpha-acetoxypropionate |
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US2408177A true US2408177A (en) | 1946-09-24 |
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US485618A Expired - Lifetime US2408177A (en) | 1943-05-04 | 1943-05-04 | Improved process for the manufacture of methyl acrylate by the thermal decomposition of methyl alpha-acetoxypropionate |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1033656B (en) * | 1953-08-12 | 1958-07-10 | Knapsack Ag | Process for the production of ª ‡, ª ‰ -unsaturated carboxylic acids and / or their derivatives |
DE1062696B (en) * | 1952-11-06 | 1959-08-06 | Minnesota Mining & Mfg | Process for the production of acrylic acid or its alkyl esters from lactic acid or lactic acid alkyl esters |
DE1118193B (en) * | 1957-09-17 | 1961-11-30 | Knapsack Ag | Process for the production of methacrylic acid esters by catalytic elimination of water from ª ‡ -oxyisobutyric acid esters |
DE1129154B (en) * | 1956-04-04 | 1962-05-10 | Minnesota Mining & Mfg | Process for the preparation of acrylic acid, methacrylic acid or their alkyl esters by splitting off hydrogen halide from ª ‡ -chloropropionic acid and their esters |
US3487101A (en) * | 1963-09-17 | 1969-12-30 | Lonza Ag | Preparation of methacrylic compounds by dehydration of alpha - hydroxybutyric acid compounds |
US9012686B2 (en) | 2010-09-23 | 2015-04-21 | Olan S. Fruchey | Acrylic acid from lactide and process |
-
1943
- 1943-05-04 US US485618A patent/US2408177A/en not_active Expired - Lifetime
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1062696B (en) * | 1952-11-06 | 1959-08-06 | Minnesota Mining & Mfg | Process for the production of acrylic acid or its alkyl esters from lactic acid or lactic acid alkyl esters |
DE1033656B (en) * | 1953-08-12 | 1958-07-10 | Knapsack Ag | Process for the production of ª ‡, ª ‰ -unsaturated carboxylic acids and / or their derivatives |
DE1129154B (en) * | 1956-04-04 | 1962-05-10 | Minnesota Mining & Mfg | Process for the preparation of acrylic acid, methacrylic acid or their alkyl esters by splitting off hydrogen halide from ª ‡ -chloropropionic acid and their esters |
DE1118193B (en) * | 1957-09-17 | 1961-11-30 | Knapsack Ag | Process for the production of methacrylic acid esters by catalytic elimination of water from ª ‡ -oxyisobutyric acid esters |
US3487101A (en) * | 1963-09-17 | 1969-12-30 | Lonza Ag | Preparation of methacrylic compounds by dehydration of alpha - hydroxybutyric acid compounds |
US9012686B2 (en) | 2010-09-23 | 2015-04-21 | Olan S. Fruchey | Acrylic acid from lactide and process |
US9290430B2 (en) | 2011-09-06 | 2016-03-22 | Sga Polymers, Llc | Acrylic acid from lactide and process |
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