Acid-Catalyzed Formation of Ethyl-Butyl Ethers in Near- and Supercritical Water

甲基叔丁基醚(一种辛烷增强剂)的全球市场在20世纪90年代的S期间预计将达到每年260亿磅。ARCO最近的一项研究得出结论，乙基叔丁基醚是一种比甲基叔丁基醚更可取的燃料添加剂。传统技术要求在合成ETBE之前先蒸馏发酵乙醇。这一建议的一个重点是在近临界或超临界水中酸催化合成ETBE，从而避免了昂贵的蒸馏。因为ETBE不溶于水，所以ETBE很容易从离开反应器的水相中分离出来。这项提议的第二个重点是在近或超临界水中由发酵产物乙醇和正丁醇在酸催化下合成乙基丁基醚(EBE)混合物。混合EBE应该具有与ETBE类似的燃料特性，并且将是一种完全可再生的高辛烷值燃料添加剂。这项研究着重于利用两个推流反应器对近临界和超临界水中酸催化的乙醚生成机理进行动力学研究。在这项工作中开发的动力学模型将对反应堆设计和放大有用。这项研究还将有助于澄清动力学在多大程度上可以用来详细说明机理。

The world-wide market for methyl tert-butyl ether (MTBE, an octane enhancer) is projected to reach 26 billion pounds per year during the 1990's. A recent ARCO study concludes that ethyl tert-butyl ether (ETBE) is a more desirable fuel additive than MBTE. Conventional technology requires distillation of fermentation ethanol prior to the synthesis of ETBE. One focus of this proposal is the acid-catalyzed synthesis of ETBE in near- or supercritical water, thereby avoiding costly distillation. Because ETBE is insoluble in water, separation of ETBE from the aqueous phase exiting the reactor is facile. A second focus of this proposal is the acid-catalyzed synthesis of a mixture of ethyl butyl ethers (EBE) in near- or supercritical water from fermentation products ethanol and 1-butanol. Mixed EBE's should have fuel properties similar the ETBE, and would be a fully renewable high octane fuel additive. The proposed research emphasizes kinetic studies of the acid-catalyzed mechanism of ether formation in near- and supercritical water using two plug flow reactors. Kinetic models developed during this work will be useful for reactor design and scale-up. This research will also help to clarify the extent to which kinetics can be used to detail mechanism.