Faria Douglas José, Moreira Dos Santos Leonardo, Bernard Franciele Longaray, Selbacch Pinto Ingrid, Carmona da Motta Resende Maria Angélica, Einloft Sandra
Post-Graduation Program in Materials Engineering and Technology, Pontifical Catholic University of Rio Grande do Sul - PUCRS Brazil
School of Technology, Pontifical Catholic University of Rio Grande do Sul PUCRS Brazil.
RSC Adv. 2020 Sep 21;10(57):34895-34902. doi: 10.1039/d0ra06034h. eCollection 2020 Sep 16.
CO emissions and global warming have increased with the growth of the world economy and industrialization. Direct synthesis of dimethyl carbonate (DMC) from CO and methanol (CHOH) has been considered a promising route from a green chemistry point of view due to global warming mitigation by CO emission reduction. However, DMC yield, when obtained by direct synthesis, is limited due to unfavorable thermodynamics and catalyst deactivation by water formation in the reaction process. This problem motivated us to investigate the effect of dehydration on DMC production by direct synthesis. Herein, different dehydrating agents (2,2-dimethoxypropane, sodium sulfate, magnesium oxide and butylene oxide) were combined with molecular sieves to remove the water and minimize the reverse reaction. A new reactor presenting a compartment to accommodate molecular sieves in the gas phase was developed as well. The chemical/product analysis was carried out by gas chromatography and the results were used to calculate methanol conversion and DMC selectivity. The highest methanol conversion value was found for the combination of molecular sieves in the gas phase with 2,2-dimethoxypropane in the reaction liquid phase (methanol conversion = 48.6% and 88% selectivity). The results showed that dehydration systems may promote increased yield in direct DMC synthesis under mild conditions. The dehydration systems tested in this work exhibited excellent conversion and yield as compared to other reported studies.
随着世界经济的增长和工业化进程，一氧化碳（CO）排放和全球变暖问题日益严重。从绿色化学的角度来看，由CO和甲醇（CH₃OH）直接合成碳酸二甲酯（DMC）被认为是一条很有前景的途径，因为它可以通过减少CO排放来缓解全球变暖。然而，直接合成法得到的DMC产率受到限制，这是由于不利的热力学条件以及反应过程中生成水导致催化剂失活。这个问题促使我们研究脱水对直接合成DMC产量的影响。在此，将不同的脱水剂（2,2 - 二甲氧基丙烷、硫酸钠、氧化镁和环氧丁烷）与分子筛结合，以去除水分并使逆反应最小化。还开发了一种新型反应器，该反应器有一个用于在气相中容纳分子筛的隔室。通过气相色谱进行化学/产物分析，并将结果用于计算甲醇转化率和DMC选择性。在反应液相中使用2,2 - 二甲氧基丙烷与气相中的分子筛结合时，发现甲醇转化率最高（甲醇转化率 = 48.6%，选择性 = 88%）。结果表明，脱水系统可以在温和条件下提高直接合成DMC的产率。与其他已报道的研究相比，本工作中测试的脱水系统表现出优异的转化率和产率。
