一步法快速提取浅色甘蔗渣木质素的工艺优化

Optimization of one-step rapid extraction of light-colored bagasse lignin

以甘蔗渣为原料,利用对甲苯磺酸(p-TsOH)一步快速分离提取浅色甘蔗渣木质素(BL)。首先,采用单因素实验法,分别考察提取温度、p-Ts OH质量分数和提取时间对BL白度和得率的影响。结果显示,BL白度随着提取时间的延长、提取温度的升高和p-TsOH质量分数的增大而不断下降,BL得率随提取时间的延长逐渐降低,随提取温度的升高和p-Ts OH质量分数的增大呈现先增加后减少的趋势。采用响应曲面设计法进一步优化浅色BL提取工艺。在提取时间15min、提取温度80℃和p-Ts OH质量分数40%的优化条件下,BL白度可高达36.11%,得率为9.59%。采用FTIR和2D-HSQCNMR对BL进行了结构表征。结果显示,BL为典型的GSH型木质素,其结构中羰基和甲氧基含量的减少有利于白度的增加。

Bagasse lignin(BL) was extracted from bagasse by p-toluenesulfonic acid(p-Ts OH) in one step rapid method. The effects of extraction time, p-Ts OH mass fraction and extraction temperature on the whiteness and yield of BL were investigated via single factor test. The results showed that the whiteness of BL decreased with the increase of extraction time, extraction temperature and p-TsOH mass fraction. The yield of BL decreased with the increase of extraction time, while that increased first and then decreased with the increase of extraction temperature and p-TsOH mass fraction. The extraction process of light-colored BL was further optimized by response surface methodology. The whiteness and yield of BL reached 36.11% and 9.59% under the optimal extraction conditions of extraction time of 15 min, extraction temperature of 80 ℃ and p-Ts OH mass fraction of 40%. The structure of BL was characterized by FTIR and 2 D-HSQC NMR. The results indicated that BL was a typical GSH-type lignin, and the reductions in contents of carbonyl and methoxyl in BL structure were beneficial to an improvement in whiteness.