摘要
根据丙二酸、乳酸脱铬过程中脱铬液pH值、铬含量和胶原水解量的变化,研究了羧基、羟基对羧酸脱铬性能的影响。结果表明:乳酸脱铬前期以H^+为主,而丙二酸脱铬随着反应温度的升高及反应时间的增加,由以H+为主转变为以酸根为主;丙二酸的脱铬性能优于乳酸,即羧基更有利于铬的脱除,羟基则加重胶原的水解;有机酸对皮胶原水解能力并不取决于其酸性的强弱,而与其脱铬时所进攻的铬的结合位点有关;胶原水解物对脱铬体系的pH值有缓冲作用,胶原水解物量越多,缓冲作用越强。
The effects of carboxyl and hydroxide groups on dechroming performance of carboxylic acids were studied according to the changes of pH values and the amounts of chrome complexes and hydrolyzed collagen proteins in the deehroming solutions when using malonic acid and lactic acid. The results showed that H＋ had higher priority for lactic acid at the early stage of dechroming process. As for malonic acid, the priority of H＋ for dechroming changed to the priority of the earboxylic group with the increase of temperature and time. The deehroming performance of malonic acid is better than that of lactic acid. This is to say that the carboxyl group enhanced the deehroming rate and hydroxide group aggravated the hydrolysis of collagen. The crucial factor influencing the ability of hydrolysis of collagen is not the acidity intensity, but the binding sites between chromium complexes and collagen which are substituted when dechroming. The collagen hydrolysis of dechroming solutions possessed buffer effect, and more amount of the collagen hydrolysis would make the stronger buffer effect.
出处
《西部皮革》
2015年第24期16-20,共5页
West Leather
关键词
丙二酸
乳酸
脱铬性能
羧基
羟基
malonic acid
lactic acid
dechroming performance
carboxyl group
hydroxide group
