Hu JiaYu, Tian Jiaxin, Wang Kai, Deng Jian, Luo Guangsheng
The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
ACS Omega. 2020 Sep 10;5(37):23736-23742. doi: 10.1021/acsomega.0c02707. eCollection 2020 Sep 22.
The selectivity of a chemical reaction is related to the effective utilization of raw materials as well as the cleanliness and economy of the process. Herein, it has been first proposed to synthesize tetraethyl thiuram disulfide (TETD) with sodium bicarbonate as the pH regulator with a reaction selectivity of ∼100%. The existence of a reaction intermediate, a sodium salt of diethyl dithiocarbamoylsulfenic acid (NaEtDTCS), has been proved by experiments and theoretical calculations. The results indicate that TETD can not only be generated from NaEtDTCS oxidized by HO directly, but also from the conjugation of NaEtDTC and NaEtDTCS generated in the first stage of oxidation meanwhile. Accordingly, an oxidation reaction pathway has been proposed. The reaction selectivity with NaHCO or CO as the pH regulator has been compared, and the selectivity control mechanism is discussed. At relatively higher pH values with NaHCO as the pH regulator, peroxidation could be almost avoided.
化学反应的选择性与原材料的有效利用以及过程的清洁度和经济性相关。在此，首次提出以碳酸氢钠作为pH调节剂合成二硫化四乙基秋兰姆（TETD），反应选择性约为100%。通过实验和理论计算证明了反应中间体二乙基二硫代氨基甲酰亚磺酸的钠盐（NaEtDTCS）的存在。结果表明，TETD不仅可以由HO直接氧化NaEtDTCS生成，还可以由氧化第一阶段生成的NaEtDTC和NaEtDTCS共轭生成。据此，提出了一条氧化反应途径。比较了以NaHCO或CO作为pH调节剂时的反应选择性，并讨论了选择性控制机制。在以NaHCO作为pH调节剂的相对较高pH值下，几乎可以避免过氧化。
