Preparation Technology Of Long-chain α-Chloro Fatty Acids

α-Chloro fatty acids are important intermediates employed for synthesizing fine chemicals such asα-amino acids and betaine-like amphoteric surfactants. Improving the synthesis process ofα-chloro fatty acids will extend the applicable field of biomass fatty acids to replace petroleum resource. In this paper, the catalysts used in the chlorination of palmitic acid were selected to investigate the catalytic mechanism. With chlorosulphonic acid as catalyst, oxygen as a scavenger, the prosessing condition of chlorination of palmitic acid was also investigated. The main points were as follows,The structure of target compound was characterized by infrared spectrum, melting point, mass spectrometry, etc. A fast gas chromatography (GC) method with capillary column was developed for the determination of long-chainα-chloro fatty acids (C12~C18). Base line separation of long-chain fatty acids and long-chainα-chloro fatty acids was achieved with in 5 minute with high resolution performance. The method is easy and low-cost and has the ability to achieve an accurate determination of long-chainα-chloro fatty acids.With chlorosulphonic acid as catalyst, oxygen as a scavenger, some processing parameters such as moisture in the reaction system, dosage of chlorosulphonic acid, reaction time, reaction temperature, flow rate of chlorine, rotate speed, ratio of V(Cl2) : V(air) and chlorosulphonic acid addition policy were investigated. With the guarantee of catalytic activity of chlorosulphonic acid, the yield of long-chainα-chloro fatty acids had a direct proportion with dosage of chlorosulphonic acid and flow rate of chlorine. Dosage of chlorosulphonic acid m(chlorosulphonic acid) : m(dodecanoic acid)= 2 % could be more reasonable in industry, and 100℃was the right temperature. Rotate speed not only accelerated the reaction, but also accelerated the escape of chlorine, and the seemly value was 300 rpm (linear speed 47~49 m/min). Reducing the proportion of V(Cl2) : V(air) less than 2:1 will produce poly-chlorinated fatty acids. Addition of chlorosulphonic acid at the beginning or many times at intervals had the same yield of long-chainα-chloro fatty acids. Antioxidant BHT and VE could not eliminate all the chlorin free group. Adding someα-CDA beforehand had no effect on accelerating the yield of long-chainα-chloro fatty acids. PTFE muddler was better than magnetic force and homogeneous machine.With chlorosulphonic acid as catalyst, oxygen as a scavenger, m(chlorosulphonic acid) : m(dodecanoic acid)=2%, 100℃, V(Cl2) : V(air) =2:1, V(Cl2) =20 L/h, 300 rpm,α-chloro-myr- -istic acid,α-chloro-hexadecanoic acid,α-chloro-stearic acid andα-chloro-SA-18640,α-chloro-SA-1865 were prepared.