Study On The Application Performance Of Scpa And Its Sodium Salt In Pickling And Tanning

In order to discuss the application performance of sulfosalicylic acid and itsderivatives4-sulphone-2-carboxy phenoxyacetic acid in the leather making,sulfosalicylic acid was etherificated to obtain4-sulphone-2-carboxy phenoxy-acetic acid by chloroacetic acid firstly in this research. Then, sulfosa-licylic acidand its derivatives4-sulphone-2-carboxy phenoxyacetic acid were used in theexperiment of less-salt pickling; sulfosalicylic acid sodium and SCPAS wereused as chrome tanning auxiliaries to detect and analyse the chrome tanningwaste float, crust and leather. Finally, the comprehensive applicationperformance of sulfosalicylic acid and its derivatives SCPA was explored.The sulfosalicylic acid was etherified by chloroacetic acid, and its yield wasdetermined by the dosage of the unreacted sulfosalicylic acid in the production.The influence of etherification reaction temperature, the ratio of raw material,etherification time and other factors on etherification degree were investigatedby single factor analysis. The results showed that the molar ratio of sulfosalicylicacid and chloro-acetic acid was1:1.05, temperature was100℃, reaction timewas3h, the yield of4-sulphone-2-carboxy phenoxyacetic acid was95.64%.Sulfosalicylic acid and SCPA are weak swelling acid, they were used inless-salt pickling. When the amount of sulfosalicylic acid was0.7%, or theamount of the SCPA was0.5%was used in less-salt pickling, the amount of saltcan be reduced to2%in pickling process, the absorption of chrome also hadraised of certain level, the indicators and performance to crust and leather bothcould meet the ordinary process requirements.Sulfosalicylic acid sodium and SCPAS were used as chrome tanning auxil-iaries in chrome tanning, the optimize application process of sulfosalicylic acidsodium was as follows: the amount of chrome powder reduced to5%in theconventional chrome tanning process,1.75%sulfosalicylic acid sodium were added in the late of chrome tanning. The optimize application process of SCPASwas as follows: in the conventional pickling chrome tanning process, the amountof chromium powder was4%, and0.75%SCPAS was added in the late ofchrome tanning.According to the uses of sulfosalicylic acid, SCPA and their sodium salt inless-salt pickling and chrome tanning, their comprehensive application processwere optimized. The optimize process of sulfosalicylic acid and its salt was that,in pickling process, the amount of salt was2%,0.8%sulfosalicylic acid wasused as pickling agent, then5%chrome powder was added, in the late of chrometanning1.2%sulfosalicylic acid sodium was used. The optimize process ofSCPA and its salt was that, the amount of pickling agent SCPA was0.5%, and2%salt was added in pickling, then4%chrome powder was added, in the late ofchrome tanning0.4%SCPAS was used to improve the absorption of chrome.The performance of the crust and leather which obtained by the comprehensiveapplication process optimization system was similar to the conventional chrometanning. The content of the chrome tanning in waste chromium was significantlyreduced, comprehensive applications effect of SCPA and its sodium salt wasbetter, the shrinkage temperature was more than95℃, which could meet withthe basic requirements of the hydrothermal stability on chrome tanned crust, andthe chromium content in the chrome tanning waste was only about30%of theconventional chrome tanning, the process approach was a viable less-saltpickling, less-chrome tanning method.