598-55-0Relevant articles and documents
CH3COONa as an effective catalyst for methoxycarbonylation of 1,6-hexanediamine by dimethyl carbonate to dimethylhexane-1,6-dicarbamate
Sun, Da-Lei,Xie, Shun-Ji,Deng, Jian-Ru,Huang, Cai-Juan,Ruckenstein, Eli,Chao, Zi-Sheng
, p. 483 - 490 (2010)
Methoxycarbonylation of 1,6-hexanediamine (HDA) by dimethyl carbonate (DMC) was carried out, using, for the first time, CH3COONa as catalyst. The effects of the solvent, reaction temperature, reaction time, and catalyst amount, were investigated. A yield as high as 99.0% of dimethylhexane-1,6- dicarbamate 2 has been obtained at a temperature of 348 K and a reaction time of 6 h. Mechanistic studies revealed that N-substituted acetamide, as the active intermediate product, and NaOH were first formed via the reaction between HDA and CH3COONa. A further reaction between the N-substituted acetamide and DMC generated carbamates and methyl acetate, via a hexatomic ring intermediate. The CH3COONa catalyst was finally recovered through the reaction between NaOH and methyl acetate, which thus completed the catalytic cycle.
Synthesis of dimethyl carbonate from methanol and urea over zinc-strontia mixed oxide catalysts
D., Dhana Lakshmi,B., Srinivasa Rao,Lingaiah
, p. 1 - 4 (2019)
A series of ZnO-SrO mixed oxide catalysts were prepared by co-precipitation with different compositions and tested for dimethyl carbonate synthesis from urea and methanol. The catalysts were characterized by BET surface area, XRD, NH3-TPD and CO2-TPD. The catalyst with 1:1 mol ratio exhibited high DMC yield of 35%. The uniform distributions of moderate to strong basic sites along with considerable number of acidic sites are accountable for high activity. Different reaction parameters were also screened and best possible conditions were established. The catalyst was easily recovered and reused with consistent activity.
Dimethyl carbonate synthesis over ZnO-CaO bi-functional catalysts
Wu, Xiaomin,Kang, Min,Zhao, Ning,Wei, Wei,Sun, Yuhan
, p. 46 - 50 (2014)
ZnO-CaO catalysts were prepared and tested for the synthesis of dimethyl carbonate (DMC) from urea and methanol. Meaningfully, the bi-functional catalysts ZnO-CaO exhibited noticeable DMC yield (41.2%) with the Zn/Ca molar ratio of 4:1, which might ascribe to the synergistic effect between ZnO and CaO. The plausible mechanism for the DMC synthesis was as follows: urea was activated to generate metal isocyanato group on the acid sites and subsequently nucleophilic attacked by the activated methanol on the basic sites.
Carbamate preparation method
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Paragraph 0026-0046, (2020/03/12)
The invention relates to a carbamate preparation method. According to the invention, dimethyl carbonate is used as a reaction raw material for urea alcoholysis, and a novel composite catalyst is used,so that the technical problems of high energy consumption and high equipment cost caused by cold energy ammonia removal in the prior art are avoided, and the yield of carbamate is up to more than 96%.
Preparation method of carbamate
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Paragraph 0034; 0038-0040, (2020/09/23)
The invention belongs to the technical field of synthesis of amino and carboxyl compounds connected to the same carbon frame through urea alcoholysis, and particularly relates to a preparation methodof carbamate. The preparation method of the carbamate comprises the following steps of: sequentially introducing urea, alcohol and a catalyst into a reactor, sealing, and reacting at 90-120 DEG C for8-12 hours to obtain the carbamate, wherein the catalyst includes an alumina supported metal oxide. By adopting the method for preparation of the carbamate, the side reaction of urea decomposition canbe effectively avoided, impurities such as carbamate are not detected, and the yield of the carbamate is high.
