The new process of abies ethanol lignin sulfation by a low-toxic mixture of sulfamic acid and urea in 1,4-dioxane medium was optimized, and the structure of sulfated ethanol lignin was studied. The process of lignin sulfation is described by a first-order equation in the temperature range 70–100 °C. The value of the rate constants is weakly dependent on the ratios of lignin and sulfating complex (sulfamic acid–urea mixture). The activation energy of the sulfation process decreases from 11.5 to 7.5 kJ/mol with an increase in the content of the sulfating complex (SC). The optimal conditions for sulfation of abies ethanol lignin with a high yield of water-soluble sulfated lignin [(100% of mass) with sulfur content of 7.9%] were found: temperature 95–100 °C, L/SC ratio 1:2.3–1:2.9, time 2 h. The composition and structure of water-soluble sulfated ethanol lignin were determined by elemental analysis, FTIR spectroscopy, two-dimensional NMR spectroscopy and gel permeation chromatography. It was shown that only alcoholic OH groups of ethanol lignin react with sulfamic acid. Sulfated ethanol lignin has a higher molecular weight and a lower degree of polydispersity compared to the initial ethanol lignin.

中文翻译：

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氨基磺酸-尿素混合物在1,4-二恶烷介质中枞木乙醇木质素硫酸化工艺优化

以氨基磺酸和尿素的低毒混合物在1,4-二氧六环介质中硫酸化冷杉乙醇木质素的新工艺进行了优化，并对硫酸化乙醇木质素的结构进行了研究。在 70-100 °C 的温度范围内，木质素硫酸化的过程由一阶方程描述。速率常数的值微弱地取决于木质素和硫酸化复合物（氨基磺酸-尿素混合物）的比例。随着硫酸化配合物(SC)含量的增加，硫酸化过程的活化能从11.5 kJ/mol降低到7.5 kJ/mol。发现了具有高产水溶性硫酸化木质素 [(100% 质量)，硫含量为 7.9%] 的枞木乙醇木质素硫酸化的最佳条件：温度 95–100 °C，L/SC 比 1:2.3 –1:2.9，时间 2 小时。通过元素分析、红外光谱、二维核磁共振光谱和凝胶渗透色谱法确定了水溶性硫酸化乙醇木质素的组成和结构。结果表明，只有乙醇木质素的醇羟基与氨基磺酸反应。与初始乙醇木质素相比，硫酸化乙醇木质素具有更高的分子量和更低的多分散度。