The method that adopts composite ionic liquid catalyst to synthesize tri-n-butyl citrate

Abstract

The invention provides a method for synthesizing tributyl citrate (TBC) by adopting a composite ionic liquid catalyst. The method is characterized by comprising the following steps: firstly carrying out esterification on taking citric acid and n-butyl alcohol which serve as raw materials in the presence of the catalyst, after esterification is qualified, directly utilizing the waste heat to reduce pressure and eliminate alcohol in a reaction kettle to obtain a crude product of tributyl citrate containing the catalyst, then carrying out acetylation and finally carrying out deacidification, standing, cooling, catalyst separation, neutralization, washing and reduced pressure distillation, thus obtaining the colorless transparent liquid TBC without decoloration and pressure filtration. The method has the following advantages: the same amount of the same catalyst is used in esterification and acetylation, thus realizing reuse of the catalyst; the conversion rate is high, the by-products are few and the yield is more than 98%; aftertreatment is simple and convenient, excessive alkaline water for neutralization and washing is not needed, the washing clear water can be reused and no pollutants are discharged; and the reaction temperature is low, the production period is short, the equipment investment is low, the energy consumption is low, and the cost is low.

Description

technical field [0001] The invention relates to a new energy-saving, high-efficiency and clean production process for synthesizing tri-n-butyl citrate (hereinafter referred to as TBC) with a composite ionic liquid catalyst. technical background [0002] At present, in the whole family of plasticizers, the most used type of plasticizer is o-phthalic plasticizer, accounting for about 70% of the entire market, and it is reported that the domestic market accounts for about 90%. A large number of studies have found that some plasticizers in this series of plasticizers have potential carcinogenicity and can indeed induce teratogenicity, mutagenesis and even death in animals, and their use has been strictly controlled abroad. my country has also formulated relevant laws and regulations to phase out the use of phthalates in food packaging materials, medical appliances, children's toys and personal hygiene products. Therefore, the application fields of traditional plasticizers will ...

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Problems solved by technology

[0006] For the tri-n-butyl citrate (TBC) production process, the problems of the traditional process are complex production process, long reaction cycle, dark product color, large equipment investment, serious corrosion, more waste water, complicated post-treatment, environmental pollution, and production cost advanced questions

[0007] Therefore, in order to achieve the purpose of esterification and acylation reaction at low temperature, short time, high conversion rate, high yield, no pollutant discharge, and easy post-treatment, processes such as decolorization and filtration are omitted, and catalysts are reused. In recent years, , the research and development and application of toluenesulfonic acid, inorganic salts, sulfamic acid, heteropolyacids, solid superacids and ionic liquids to replace sulfuric acid catalysts are increasing (for example, Xie Wenlei et al. "Fine Petrochemical Industry" 1998, 4: 7- 9; Deng Xuzhong et al. "Fine Chemical Industry" 2001, 18(2): 83-85; Mao Lixin et al. "Journal of Hunan Institute of Technology" 2005, 18(2): 36-38; Liu Bing et al. CN101402571A; Yan Leng et al.Angew .Chem.Int.Ed.2009, 48: 168-171; Teng Junjiang et al. "Industrial Catalysis" 2010, 18: 67-70; Cai Zhuanghong, Zhengzhou University master's thesis "Annual production of 500 tons of non-toxic plasticizer acetylcitric acid Tributyl Ester Process Design" 2005; Wang Tao et al., 200810042466.2; Yang Jianguo et al., 200610024372.3, but no reports of successful industrial production

The improvement in reaction conversion rate, selectivity, catalytic activity, product color lightening, reduction of waste water volume, catalyst recycling, environmental protection, etc. obtained by these methods cannot be said to be sufficient.

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