A Study On The Synthesis Of β-Ionone In A Higee Reactor

β-ionone is an important compound with a great commercial value as it is widely used as a spice and pharmaceutical intermediate in the chemical industry. It is commonly synthesized by cyclization reaction of pseudoionone catalyzed by sulfuric acid. This technique is typically a rapid exothermic cyclization reaction which highly requires efficient mixing of the reacting raw materials in order to minimize the occurrence of hot spots in the reaction system. As such, this synthesis method requires a large amount of organic solvent, and moreover, it has low yield and difficult to operate. Since the efficiency of mixing and mass-transfer has direct influence on the distribution of the products, it is necessary to improve the mixing and mass transfer processes in the rapid reaction system in order to improve the quality of the product.Higee reactor (RPB) is a novel device which can create a large centrifugal force field through high-speed rotation of the rotor and thereby intensifies the mixing and mass transfer processes. This technology has been extensively employed in several fields including nano-materials preparation, flue gas desulfurization and denitrification, etc.This work employed higee reactor to synthesize P-ionone and compared the product quality with those prepared in the traditional stirred tank reactor (STR). The research findings were as follows:(1) As for the aldol condensation reaction of citral and acetone in a stirred tank reactor, the optimum synthesis condition is as follows: citral/acetone mole ratio=1:9, the catalyst NaOH (10%)/citral molar ratio=0.12:1, reaction temperature 50℃, reactor residence time=3h, the highest yield of pseudoionone was 89%.(2) The optimum synthesis condition for the cyclization reaction of pseudoionone in a stirred tank reactor, is as follows: Pseudoionone/CH2C12 (vol) ratio=1:9, H2SO4/Pseudoionone molar ratio =4:1, T=20℃, reactor residence time=10 min, the highest yield of β-ionone was 90%.(3) Results of the research on the continuous synthesis process of P-ionone in Higee reactor suggest that the optimum reaction condition is as follows:H2SO4/Pseudoionone molar ratio=12:1, Pseudoionone: CH2Cl2(vol)=1:5, N=1700 rpm, T=16-20℃,β-ionone yield reaches to 90%.Results of the research on the recycle synthesis process of P-ionone in Higee reactor suggest that the optimum reaction condition is as follows: H2SO4:Pseudoionone (mol)=4:1, Pseudoionone:CH2Cl2 (vol)=1:3, rotating speed=1700 rpm, T=20℃, β-ionone yield reaches to 93%.In comparison with the traditional reactor, the Higee reactor can reduce the amount of solvent used in the synthesis; increase the yield of the β-ionone, and the throughput capacity.