Studies On The Preparation Of Quaternary Phosphonium-type Triphase Catalysts And Catalytic Activity Based On CPS

Quaternary phosphonium-type triphase catalysts have been used to catalytic the organic reactions system of triphase liquid-liquid and liquid-solid; this is one of the most important domains of triphase catalysts at present. Three kinds of quaternary phosphonium -type triphase catalysts which have spacer arms with different lengths were prepared based on crosslinked polystyrene microspheres (CPS). Focus on exploring the relationship between catalysts structure and catalytic activity. This has important scientific significance and application value in the study field of phase transfer catalysis and chemical production practice.Friedel-Crafts acylation reaction of crosslinked polystyrene microspheres was conducted using two kinds ofω-chloroacyl chloride, chloroacetyl chloride and chlorobutyryl chloride, and chloroacylation crosslinked polystyrene microspheres were prepared. The chemical structure and composition of the product microspheres were characterized and determined by infrerad spectroscopy and Volhard methods. The effects of various factors on the chloroacylation reaction were investigated. The experimental results show that the chloroacylation process is always attended by Friedel-Crafts alkylation reaction, which is a side reaction leading to additional crosslinking. This side reaction not only decreases the content of the chloroacyl groups on CPS microspheres, but also makes the property of the microspheres tobe poor. The additional crosslinking reaction can be avoided so as to enhance the content of the chloroacyl groups by adopting suitable reaction conditions and controlling some factors, for example, using SnCl4 as catalyst and CHCl3 as solvent, as well as effectively controlling the reaction time. The result still indicates that the chlorine content of CACPS microspheres is the highest is 9% and the chlorine content of CBCPS microspheres is the highest is 12% in the appropriate reaction conditions. Three kinds of modified microspheres CACPS, CBCPS and CMCPS were transferred into quaternary phosphonium-type triphase catalysts via quaternary phosphonium (QP) reaction and with triphenylphosphine as reagent. Three kinds of quaternary phosphonium-type triphase catalysts QP-CPS (QP-CACPS, QP-CBCPS and QP-CMCPS) which have spacer arms with different lengths were obtained. The chemical structure and composition of the triphase catalysts were characterized and determined by infrerad spectroscopy. And the quaternary phosphonium degree was gained by the spectra of UV/Vis. The effects of main factors on quaternary phosphonium reaction were examined. The experimental results indicate that the quaternary phosphonium degree of QP-CACPS is the highest is 47% with CH2Cl2 as solvent at 35℃. In the appropriate conditions, the modified microspheres CBCPS and CMCPS were quaternary phosphonium reaction. Due to steric effect, modified microspheres with a shorter spacer arm have slower the rate of quarter phosphonium. By controlling the reaction time, the catalyst which has different quaternary phosphonium degree can be obtained.The phase-transfer catalysis activities of the prepared triphase catalysts were investigated using the reaction system of the esterification between benzyl chloride and sodium acetate as a model system of phase-transfer catalysis and carried out in-depth study from the reaction kinetics. The experimental results indicate that the prepared quaternary phosphonium-type tricatalysts have higher activities for the synthesis of benzyl acetate. Reaction after 13 hours, benzyl chloride conversion reaches 65% in the precence of QP-CACPS catalyst with CHCl3 as solvent at 57℃. In comparison with quaternary ammonium-type (QN) catalyst QN-CPS, the quaternary phosphonium-type triphase catalysts QP-CPS have higher catalytic activity. The catalyst QP-CPS with a longer spacer arm has higher catalytic activity.The reaction that phthalimide as the reagent of nucleophilic substitution reacts with 1-bromobutane to synthetic N-butyl phthalimide via N-alkylation reaction is an important organic reactions. The activity of QP-CPS and the effects of various factors on the phase-transfer catalysis reaction were examined using this reaction system of as a model system of phase-transfer catalysis. Focus on exploring the relationship between catalysts structure of spacer arm and catalytic activity and carried out in-depth study from the reaction kinetics. The experimental results indicate that the prepared quaternary phosphonium-type tricatalysts have higher activities for the synthetic N-butyl phthalimide. The optimal reaction conditions include that the nitrobenzene as the organic phase, using the catalyst (QP-CBCPS) of longest spacer arm structure, water phase volume ratio of 1:4, and the agitation rates higher than or equal to 550 r/min, and the conversion of 1-bromobutane can reach 87% when the amount of catalyst was 4mmol, at a reaction temperature of 90℃for 12 h in the appropriate reaction conditions. From the effect of quaternary phosphonium-type triphase catalysts QP-CPS which have spacer arms with different lengths, we can see that the longer the spacer arm of the QP-CPS, the stronger the catalytic activity.