High-efficiency environment-friendly ketene dimer production technique

Abstract

The invention discloses a high-efficiency environment-friendly ketene dimer production technique which comprises the following steps: (1) gasifying an acetic acid water solution into acetic acid gas, mixing with a catalyst phase, and cracking in a cracking furnace at 680-698 DEG C to generate ketene gas, wherein the outlet pressure of the cracking furnace is controlled at the absolute pressure value of 2-20 KP; (2) delivering the purified ketene gas to an absorption unit with a vacuum pump, wherein the pressures before and after the pump are respectively 2-20 KP and 100-120 KP, and the temperature difference change of the absorption liquid is controlled to be less than 10 DEG C; (3) respectively sending the absorption liquid into a high temperature polymerization tank and a low temperature polymerization tank to perform primary and secondary polymerization, thereby obtaining the crude product ketene dimer; (4) carrying out vacuum rectification on the crude product ketene dimer to obtain a ketene dimer finished product; and (5) under the action of a combustion-supporting oxidizing gas medium, delivering the rectification residue to a combustion furnace to perform oxidation treatment while controlling the delivery pressure at 6-10 kgf / cm<2>. The technique has the advantages of fewer side reactions, high product yield and no solid waste generation.

Description

technical field [0001] The invention relates to a production process for producing diketene by thermal cracking with acetic acid as raw material. Background technique [0002] Diketene, also known as diketene, is a colorless or light yellow liquid with a strong pungent odor. Because diketene contains two double bonds in its structure and is highly unsaturated, it has high chemical activity and excellent reaction in organic synthesis. It is an important intermediate and acetoacetylating agent in organic synthesis, and is widely used in medicine, pesticides, dyes, food and other industries. [0003] The acetic acid cracking method is a commonly used method to produce diketene. The production process of the acetic acid cracking method is as follows: the acetic acid aqueous solution with a mass concentration of about 92% is heated and vaporized, and then mixed with a phosphate aqueous solution catalyst with a mass concentration of 10% and enters together. The preheating sectio...

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Problems solved by technology

[0004] The shortcoming of above-mentioned acetic acid cracking method to produce diketene technology is: one, in the acetic acid cracking process can produce more by-products such as carbon monoxide, carbon dioxide, methane; High polymers such as tetraketene ketone affect the quality and yield of the final product diketene; 3. A large amount of solvents are used in the treatment of rectification residue, which increases the treatment cost and the pressure of environmental protection.