乙醛酸/2-氨基-1,4-苯二磺酸Schiff碱的制备与助浸酸性能

Preparation of A Schiff Base of Glyoxylic Acid and 2-Amino-1,4-Benzenedisulfonic Acid and its Application in Pickling Process

以乙醛酸和2-氨基-1,4-苯二磺酸为原料,制备了一种富含磺酸基和羧基的Schiff碱,将得到的Schiff碱作为浸酸助剂应用于制革浸酸过程,采用FTIR、1HNMR、ESEM、EDS对其结构进行了表征,对酸皮膨胀度、蓝皮收缩温度(Ts)、废液铬含量进行了测试。结果表明:质量分数2.0%(以灰皮质量为基准,下同)的浸酸助剂应用于无盐浸酸,皮块膨胀度为4.15%,在此基础上复配质量分数1.0%的Na Cl,皮块不膨胀。将质量分数4.5%的铬粉应用于少盐浸酸铬鞣,Ts可以达到105.5℃,与常规铬鞣蓝湿革Ts(106.3℃)相当;与传统浸酸铬鞣相比,废液中Cr_2O_3的质量浓度从3.305 g/L下降至1.546 g/L,Cl-的浓度从374.2 mmol/L下降至59.6 mmol/L。ESEM结果表明:少盐浸酸铬鞣蓝湿革纤维分散均匀,粒面平整,毛孔清晰。EDS结果表明:铬元素的皮块纵切面方向分布均匀。少盐浸酸铬鞣工艺处理的成革抗张强度、断裂伸长率及撕裂强度较传统浸酸铬鞣工艺分别提高至32.8 MPa、56.8%和80.2 N/mm。

A Schiff base containing sulfonic acid group and carboxyl group was prepared from glyoxalic acid with 2-amino-1,4-benzenedisulfonic acid and then used in pickling process as pickling auxiliary.Subsequently,the structure of the compound,the swelling rate of acidic pelts,shrinking temperature of wet-blue leather,Cr2O3 content of the tanning wastewater were determined by FTIR,1HNMR,ESEM and EDS. The result showed that when 2. 0% pickling auxiliary（ based on limed pelts weight,the same below） was used in salt-free pickling,the swelling degree of pickled pelts was 4. 15%,however,when1. 0% sodium chloride was added into the above system,pickled pelts didn＇ t swell. Moreover,when4. 5% chrome powder was applied to the above-mentioned less salt pickling chrome tanning,the shrinking temperature（ Ts） of wet-blue leather reached 105. 5 ℃,Tsof traditional pickling chrome tanning was 106. 3 ℃. Compared with traditional pickling chrome tanning process,this process made the concentration of Cr2O3 and Cl^-of waste tanning liquor reduced from 3. 305 g / L and 374. 2 mmol /L to 1. 546 g / L and 59. 6 mmol / L,respectively. The ESEM observation showed that the fiber of wetblue leather dispersed evenly,with smooth grain and clear pores during less salt pickling process. And the EDS measurement revealed that chromium elements were uniformly dispersed in cross section of pelts. The tensile strength,elongation at break and tear strength were up to 32. 8 MPa,56. 8% and80. 2 N / mm,respectively.