The chitosan phosphotungstate was prepared and used for synthesis butyl acetate from n-butyl alcohol and acetic acid.The influences of catalyst quantity,molar ratio of n-butyl alcohol to acetic acid,reaction time and ...The chitosan phosphotungstate was prepared and used for synthesis butyl acetate from n-butyl alcohol and acetic acid.The influences of catalyst quantity,molar ratio of n-butyl alcohol to acetic acid,reaction time and the pH of catalyst preparation on the yield were studied.The results show that chitosan phosphotungstate offer good catalytic activity in esterfication.When the catalyst was prepared in acidic aqueous solution,mass ratio of catalyst to acetic acid was 5%,molar ratio of alcohol to acid was 1.3∶1 and the reaction time was 5h,the yield of n-butyl alcohol was up to 54%.The catalyst can be used repeatedly.展开更多
Cyclohexanone ethylene glycol ketal was synthesized from cyclohexanone and ethylene glycol in the presence of chitosan sulfate.The influence factors were investigated.The results showed that the appropriate conditions...Cyclohexanone ethylene glycol ketal was synthesized from cyclohexanone and ethylene glycol in the presence of chitosan sulfate.The influence factors were investigated.The results showed that the appropriate conditions were as follows:the amount of cyclohexane was 10mL per 0.1mol cyclohexanone,the molar ratio of cyclohexanone to ethylene glycol was 1∶1.5,mass ratio of catalyst to cyclohexanone was 3% and the reaction time was 90 minutes.The yield of cyclohexanone ethylene glycol ketal reached over 85%.The catalyst could be used repeatedly.展开更多
介绍了以环氧乙烷、乙酸乙酯为原料,Mg Al O体系(镁铝复合氧化物,LDO)作为催化剂,一步合成乙二醇单乙醚醋酸酯(EGEEA)的方法。系统考察了催化剂前体-水滑石(LDH)的制备条件和后期煅烧条件,如滴加方式、滴加过程的pH值、镁铝比、煅烧时...介绍了以环氧乙烷、乙酸乙酯为原料,Mg Al O体系(镁铝复合氧化物,LDO)作为催化剂,一步合成乙二醇单乙醚醋酸酯(EGEEA)的方法。系统考察了催化剂前体-水滑石(LDH)的制备条件和后期煅烧条件,如滴加方式、滴加过程的pH值、镁铝比、煅烧时间、晶化时间和煅烧温度等对LDO性能的影响。实验结果表明,未经晶化的水滑石制得的催化剂活性偏低。部分制备条件影响LDO的选择性。对LDO的煅烧条件研究结果表明,煅烧温度、煅烧时间均影响LDO的活性和选择性。乙二醇单乙醚醋酸酯收率为39 83%。展开更多
文摘The chitosan phosphotungstate was prepared and used for synthesis butyl acetate from n-butyl alcohol and acetic acid.The influences of catalyst quantity,molar ratio of n-butyl alcohol to acetic acid,reaction time and the pH of catalyst preparation on the yield were studied.The results show that chitosan phosphotungstate offer good catalytic activity in esterfication.When the catalyst was prepared in acidic aqueous solution,mass ratio of catalyst to acetic acid was 5%,molar ratio of alcohol to acid was 1.3∶1 and the reaction time was 5h,the yield of n-butyl alcohol was up to 54%.The catalyst can be used repeatedly.
文摘Cyclohexanone ethylene glycol ketal was synthesized from cyclohexanone and ethylene glycol in the presence of chitosan sulfate.The influence factors were investigated.The results showed that the appropriate conditions were as follows:the amount of cyclohexane was 10mL per 0.1mol cyclohexanone,the molar ratio of cyclohexanone to ethylene glycol was 1∶1.5,mass ratio of catalyst to cyclohexanone was 3% and the reaction time was 90 minutes.The yield of cyclohexanone ethylene glycol ketal reached over 85%.The catalyst could be used repeatedly.
文摘介绍了以环氧乙烷、乙酸乙酯为原料,Mg Al O体系(镁铝复合氧化物,LDO)作为催化剂,一步合成乙二醇单乙醚醋酸酯(EGEEA)的方法。系统考察了催化剂前体-水滑石(LDH)的制备条件和后期煅烧条件,如滴加方式、滴加过程的pH值、镁铝比、煅烧时间、晶化时间和煅烧温度等对LDO性能的影响。实验结果表明,未经晶化的水滑石制得的催化剂活性偏低。部分制备条件影响LDO的选择性。对LDO的煅烧条件研究结果表明,煅烧温度、煅烧时间均影响LDO的活性和选择性。乙二醇单乙醚醋酸酯收率为39 83%。
文摘研究海带多酚提取物对冷藏中国对虾品质变化的影响,以延长冷藏对虾的保鲜期.在预实验的基础上,用0.2%海带多酚提取物处理对虾120 min,置于(4±0.5)℃下贮藏,以去离子处理为对照;定期测定贮藏期间对虾的细菌总数(TVC)、pH值、挥发性盐基氮(TVB-N)、硫代巴比妥酸(TBA)、K值、感官和质构等指标的变化.结果表明:海带多酚提取物可以显著延缓冷藏过程中对虾TVC值、pH值、TVB-N值、TBA值和K值的上升,抑制对虾弹性的下降,降低腐败劣变的速度.与对照相比,0.2%海带多酚提取物处理可延长冷藏中国对虾保鲜期2 d.
