One-Pot Synthesis of Dimethyl Carbonate from Methanol, Propylene Oxide and Carbon Dioxide Over Supported Choline hydroxi
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One-Pot Synthesis of Dimethyl Carbonate from Methanol, Propylene Oxide and Carbon Dioxide Over Supported Choline hydroxide/MgO Chunyan De Æ Bin Lu Æ He Lv Æ Yuanyuan Yu Æ Yu Bai Æ Qinghai Cai
Received: 1 October 2008 / Accepted: 9 November 2008 / Published online: 26 November 2008 Ó Springer Science+Business Media, LLC 2008
Abstract A basic ionic liquid, namely choline hydroxide, was prepared and supported on MgO to form Choline hydroxide/MgO material. The supported ionic liquid material was characterized by XRD, FT–IR and TG and used as a catalyst in one-pot synthesis of dimethyl carbonate from propylene oxide, methanol and carbon dioxide. A good catalytic performance was obtained with 98% conversion of epoxide and selectivity of above 90% to DMC ? PC over the composite catalyst. However, the catalyst could be reused three times without a significant change in its catalytic activity. Keywords Ionic liquid Dimethyl carbonate Methanol Carbon dioxide Propylene oxide
1 Introduction Dimethyl carbonate (DMC) is a green chemical that has been paid too much attention in recent years. It can be effectively used as an environmentally benign substitute for highly toxic phosgene and dimethyl sulfate in carbonylation and methylation reaction, as monomer for several types of polymers and an intermediate in the synthesis of pharmaceutical and agricultural chemicals [1]. Also, DMC can be used as a promising octane booster due to its high oxygen content [2]. Currently, DMC is produced by
C. De B. Lu H. Lv Y. Yu Y. Bai Q. Cai (&) College of Chemistry and Chemical Engineering and Provincial Key Lab for Nano-Functionalized Materials and Excitated State, Harbin Normal University, No. 50 Hexing road Nangang District, 150080 Harbin, People’s Republic of China e-mail: [email protected]
phosgene and non-phosgene route, but phosgene route is limited for the use of toxic phosgene. For the non-phosgene route, DMC is mainly prepared by the oxidative carbonylation of methanol and the two-step transesterification from epoxide, methanol and CO2 in the bulk production. However, the oxidative carbonylation of methanol suffers from the low production rate, the need for corrosion resistant reactors, the toxicity and potential explosion of carbon monoxide. Besides, the major disadvantages of this two-step process are high energy consumption, high investment and production costs due to the requirement of the intermediate separation, i.e., cyclic carbonate. The onepot synthesis of DMC from carbon dioxide, methanol and ethylene or propylene oxide shown in Scheme 1 was, therefore, developed in order to avoid the separation of the intermediate ethylene or propylene carbonate in the two step trans-esterification. Several catalysts, such as inorganic base composites and/or basic metal oxide [3–6], Re(CO)5Cl/K2CO3 [7], KOH/4A molecular sieve [8], n-Bu4NBr/n-Bu3 N [9], [bmim]/BF4 [10], Mg containing. Smectite [11], heterogeneous anion exchange resins [12] and inorganic base/phosphonium halide functionalized polyethylene glycol [13] et
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