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  • 简介:译文:一个很吝啬的人决定请一次客,他给朋友打电话说:“请你今天晚上来我家,用你的胳膊肘按门铃。门开了后,再用你的脚把门推开。”

  • 标签: 小学生 英语学习 阅读知识 课外阅读
  • 简介:夏季里,黑白或是糖果色,都会成为街头的主角。相同的颜色,近似的款式,平价与品牌,美眉自己来选择吧!

  • 标签: 投资 品牌 平价
  • 简介:TheesterificationoflauricacidwithmethanolcouldbeefficientlycatalyzedbyZrOCl2·8H2O,andthisreactionwasstudiedtodevelopagreenmethodforbiodieselproduction.Theinfluencingfactors,suchasamountofcatalyst,reactiontimeandmolarratioofacidtomethanol,wereinvestigated.TheresultsindicatedthattheZrOCl2·8H2Ocatalystshowedhighcatalyticactivity,andgavea97.0%methyllaurateconversionrateunderthefollowingoptimizedconditions,viz.:alauricacid/methanolmolarratioof1:10,acatalystdosageof4%,andareactiondurationof2hatmethanolrefluxingtemperature.Thecatalystcouldbeeasilyrecoveredwhileitsactivitycouldbewellretainedafterthreecycles.TheZrOCl2·8H2Ocatalystalsoexhibitedexcellentcatalyticactivityfortheesterificationofdifferentfreelong-chainfattyacids(includingnonedibleoilswithhighacidvalue)withdifferentshortcarbonchainalcohols.Therefore,theZrOCl2·8H2Ocatalysthasgoodpotentialforthesynthesisofbiodieselfromlow-costfeedstockssuchaswastevegetableoilsandnon-edibleoils.

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