| 摘要 |
<p>A high-boiling base product containing polymeric material which is obtained in the production of an alkyl ester of acrylic acid by reaction between an alkanol and acrylic acid is depolymerized by heating to a temperature of about 200 DEG to about 350 DEG C. in the substantial absence of molecular oxygen, and a fraction containing the reformed monomers is taken off overhead. The base product may previously be treated to remove any volatile monomers present therein, for example by treatment in a film evaporator as disclosed in Specification 923,594. Atmospheric pressure is preferred for the cracking reaction but higher or lower pressures may be used and a stream of inert gas such as nitrogen may be passed through the liquid material being cracked. A cracking catalyst may be present and may be the esterification catalyst present in the base product as withdrawn from the esterification reactor. Examples are given of the treatment of a base product obtained according to Specification 923,594, the products being principally ethyl acrylate and acrylic acid.ALSO:A high-boiling base product containing polymeric material which is obtained in the production of an alkyl ester of acrylic acid by reaction between an alkanol and acrylic acid is depolymerized by heating to a temperature of about 200 DEG to about 350 DEG C. in the substantial absence of molecular oxygen, and a fraction containing the reformed monomers is taken off overhead. The base product may previously be treated to remove any volatile monomers present therein, for example by treatment in a film evaporator as disclosed in Specification 923,594. Atmospheric pressure is preferred for the cracking reaction but higher or lower pressures may be used and a stream of inert gas such as nitrogen may be passed through the liquid material being cracked. A cracking catalyst may be present and may be the esterification catalyst present in the base product as withdrawn from the esterification reactor. Recovered acrylic acid may be recycled to the esterification. Examples are given of the treatment of a base product obtained according to Specification 923,594 and specific products obtained by the cracking reaction are acetaldehyde, diethyl ether, ethanol, ethyl acetate, ethyl acrylate, acetic acid, acrylic acid, ethyl b -ethoxypropionate and ethyl b -acetoxypropionate.</p> |
