Stearoyl chloride phosgene recovery method

Abstract

The invention provides a stearoyl chloride phosgene recovery method. The method comprises the following steps that firstly, tail gas generated stearoyle chloride production is introduced into a falling-film absorption tower; secondly, the temperature-increased gas is introduced into a cooling tower; thirdly, the cooled materials are introduced into a NaOH solution; thirdly, the discharged materials are transferred into a synthesizing kettle to be heated; fourthly, the materials of which the gas is exhausted are heated and filtered, and meanwhile the exhausted gas is continuously introduced into the NaOH solution; lastly, the gas is introduced into a filtering tank with drying agents, and then the gas is recovered. According to the stearoyl chloride phosgene recovery method, the production technology is adopted, and meanwhile temperature control is very important; the rest gas in the tail gas can be removed, and environmental pollution caused by direct emission of the tail gas is avoided; meanwhile, phosgene can be further recovered, the cost is lowered, the overall phosgene waste can be reduced, and the purity of the recovered recoverable phosgene is 69.9%-78.9%.

Description

technical field [0001] The invention relates to the field of plastic fine chemical production, in particular to a phosgene recovery method of stearoyl chloride. Background technique [0002] Stearoyl acid chloride (Stearoyl acid chloride, also known as octadecanoyl chloride) is a pesticide intermediate, and also a raw material for the production of neutral sizing agent for papermaking - alkyl ketene dimer (AKD). Under the catalysis of methyl formamide (DMF), it reacts with phosgene. [0003] In the process of catalytic photochemical reaction, DMF, stearic acid and stearyl chloride have side reactions to generate complex tar-like colored substances. Stearyl chloride is a heat-sensitive substance. When it exceeds a certain temperature, it will undergo a polymerization reaction to produce tar, and the tar The amount produced increases rapidly with the increase of temperature and the extension of heating time. Therefore, only rapid gasification under lower temperature conditio...

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Problems solved by technology

Therefore, only rapid gasification under lower temperature conditions can successfully achieve distillation decolorization. Under conventional rectification conditions, the tar generation rate is too high, and activated carbon is generally used for decolorization. Diverse, for example, phosgene will be excessive, so that stearic acid can be completely reacted, but phosgene will react with water at the same time to produce hydrogen chloride gas and carbon dioxide gas, as well as the tail gas produced by some other side reactions, because the tail gas cannot be processed directly Exhausting it into the air will affect the environment, and at the same time, a large amount of exhaust gas such as phosgene cannot be recycled, which will cause a certain amount of waste