The Syntheses Of Alkylamides And The Laws Research Of Extracting Carboxylic Acids With Alkylamides

Organic acids are widely used in many fields. Currently, Extraction and Separation of organic acids in the fermentation broth has some drawbacks, such as extractant easy to emulsify, loaded organic phase hard to stripping, serious environmental pollution and so on. This thesis focuses on the development of new alkyl amide extracting agent, and the extractions of organic acids with alkylamides extractant. Finally N214 solves the technical problem of hydroxy acid extraction separation.The five kinds alkyl amides of N214, N216, N103, N504, N266 were synthesized with the way of acyl ahloride. Through single factor test, the best synthesis conditions are optimized as follows: the material ratio of amine with an acyl chloride 2:1, dropping temperature 0 ~ 5 oC, dropping rate of 1 s / drop. Synthesis conditions of N214 alkylamide using the way of acid anhydride are optimized as follows: material ratio of amine with acid anhydride 1:1, dropping temperature 5 ~ 10 oC, dropping rate of 3 s / drop, concentrated sulfuric acid as catalyst.The effects of alkylamides extractants, phase modifier and solvents in the extraction system on extraction rate, back extraction ratio and degree of emulsification are studied. The results are as follows: Alkane diluent was an inert diluents, alcohol diluent was a reactive diluents; There was chemical complex extraction between the hydroxy acid and alcohol diluents and physical extraction between alcohol diluent and non-hydroxy acid; Non-hydroxy carboxylic acid and unsaturated carboxylic acids were ready to extract while hydroxy carboxylic acid is difficult to extract by alkylamides extractants. The research of two phases distribution equilibrium theory clear polar organic carboxylic acids and organic acids with two immiscible phases intermolecular forces that affect the main reason for its extraction performance.Extracting non-hydroxy acid with alkylamide extractants, the results show that extraction rate keeps steady at 30%, while extracting hydroxy acid with these extractants, the result is not optimistic and the extraction rate is less than 5%. To our surprise, hydroxy acids are difficult to be extracted, which problem was solved with N214 as extractant. The optimum conditions were as follows: extraction temperature 30 oC, phase ratio 1:1, back-extraction temperature 60 oC, reaction time 10 min. The countercurrent extraction stages were 9 stages and the countercurrent back extraction stages were 5 stages. The target separation of citric acid from the fermentation broth was achieved and the qualified citric acid products was obtained. The complex structure is determined by double logarithmic method and IR spectroscopy analysis, indicating that extraction reaction of complex agent with citric acid occurs through ion association and hydrogen bond, A118 does not participate in the chemical reaction. This thesis analyzed the thermodynamic extraction process, the process of alkylamide extracting polybasic acids was exothermal process. The monohydroxy carboxylic acids extraction is nearly dependent of temperature. Therefore, the extraction operation of alkylamide extracting multiple carboxylic acids should be completed under the normal temperature.