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• 2018-12-07 00:23发布了问答

  如何选择反应釜材质及搅拌器

  　

  220人看过

• 2018-11-21 10:26发布了问答

  反应釜密封有摩擦声音，是不是缺密封油了

  　

  341人看过

• 2018-11-19 13:52发布了问答

  反应釜风量问题？

  现在有一个反应釜的吸风口连接到焚烧炉，要求吸风口的流量，计算方法是否是管径截留面积乘以风速？

  264人看过

• 2018-11-17 13:49发布了问答

  谁能告诉我 合成体 的概念，谢谢！

  　

  284人看过

• 2018-03-18 13:27发布了问答

  与化学合成药相比，生物药物分析有何特点?

  与化学合成药相比，生物药物分析有何特点?

  856人看过

• 2017-10-14 03:34发布了问答

  如何对催化剂的寿命和再生进行评价或表征

  　

  409人看过

• 2017-02-11 19:54发布了问答

  水热反应釜的安全性？

  　

  676人看过

• 2015-05-25 16:25发布了问答

  饲料中能添加化学合成的叶黄素吗

  　

  456人看过

• 2015-04-15 19:36发布了问答

  搅拌反应釜电机该怎么弄

  做毕业设计发现搅拌轴的转速要变，但是我不知道该怎么弄。 液体洗涤剂生产工艺简介： 该液体洗涤剂各种原料由高位储料槽依次加入反应釜至规定液位，加料完毕后，用蒸汽加热物料，并低速搅拌（n=40rpm）。当温度升至500C后改为高速（n=85rpm）搅拌。温度... 做毕业设计发现搅拌轴的转速要变，但是我不知道该怎么弄。 液体洗涤剂生产工艺简介： 该液体洗涤剂各种原料由高位储料槽依次加入反应釜至规定液位，加料完毕后，用蒸汽加热物料，并低速搅拌（n=40rpm）。当温度升至500C后改为高速（n=85rpm）搅拌。温度升至600C时进入恒温搅拌过程，3小时后停止加热搅拌，Z后用冷水降温至400C出料包装。 展开

  526人看过

• 2015-01-14 21:48发布了问答

  怎么安装才能保证反应釜搅拌轴同心

  　

  532人看过

• 2008-11-30 22:53发布了问答

  手机 电脑 电视 微波等辐射对人的危害以及FZ

  多吃水果和喝茶是吧... 多吃水果和喝茶是吧 展开

  448人看过

• 2008-05-21 01:00发布了问答

  英语翻译(2)

  Keywords:Epoxides;Amines;2-Aminoalcohols;Yttriumnitratehexahydrate;RegioselectivityAminoalcoholsconstituteanimportantclassofcompoundshavingbothchemicalandbiologicalapplic... Keywords: Epoxides; Amines; 2-Amino alcohols; Yttrium nitrate hexahydrate; Regioselectivity Amino alcohols constitute an important class of compoundshaving both chemical and biological applications. They are important pharmacophores present in various inhibitors and are used as building blocks for the synthesis of biologically active natural products， insecticidal agents and chiral auxillaries for asymmetric reactions.1a–f They act as starting materials for the synthesis of oxazolines which are useful in the polymer industry.1g Owing to their widespread applications， the synthesis of amino alcohols has received much attention in recent years. Traditionally， 2-amino alcohols are prepared by heating an epoxide with an excess of amine at elevated temperature. The use of a high temperature leads to undesired side reactions and also limits the applicability towards temperature sensitive substrates. To overcome these drawbacks various promoters such as ZnCl2，2 ScOTf，3 MgBr2OEt2，4 67 9 bismuth salts，5 CoCl2， CuBF4， DIPAT，8 Ti(OiPr)4， 1011 12TaCl5， ZrCl4， Sm(OTf)3， potassium dodecatungstocobaltate， 13 and aluminosilicate14 have been employed for the above transformation. The use of non-conventional techniques such as microwave irradiation at elevated temperaturehas also been reported.15 Recently， the use of Al(OTf)3 (1 mol %) as catalyst in toluene at reflux has also been reported.16 Although significant advances have been made in this area， low regioselectivity， longer reaction time， use of elevated temperature， high catalyst loading， toxic solvents and lower substrate compatibilitylimit their applications.Thus there is a need to develop an efficient catalytic protocol for ring opening of various epoxides with aliphatic， aromatic andheteroaromatic amines under ambient conditions 展开

  308人看过

• 2006-07-14 08:17发布了问答

  核裂变和核聚变分别是怎么一会事

  核裂变和核聚变分别是怎么一会事... 核裂变和核聚变分别是怎么一会事 展开

  442人看过