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feng2006铜虫 (小有名气)
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[交流]
求助翻译一段话到英文---有效期至2009-8-16
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本人英语实在很差。。拜托了，能翻译几句是几句。。。。。。 2.3 温度、压力的影响 酯交换反应可在不同的温度下进行，不同的原料有不同的适宜温度。常压下，酯交换反应的温度以60℃为宜。陈秀等[8]的研究了用1%NaOH催化，醇油比为6:1，反应1h，反应最佳温度为60℃时,甲酯产率达到94%。如果反应温度从60℃继续升高，将会逐渐接近并超过甲醇的沸点，使反应系统中的大量甲醇挥发成气相，从而降低液相中甲醇浓度，会导致反应产率的下降。 超临界状态下，当反应温度、压力在甲醇临界温度239.4℃，临界压力8.09MPa附近时[9]，甲醇的超临界状态不是很好，不能很好的溶于油脂，反应速度和产率都不很高；随着压力和温度的升高，反应速度和甲酯产率都会有所提高，但温度超过甲醇的临界温度太高会有热裂解、结焦等副反应发生。压力对酯交换反应转化率有明显影响，随着压力升高，甲醇介电常数逐渐降低并接近于标准状态下一般有机溶剂介电常数，此时它表现出更近似于非极性有机化合物性质，对油脂溶解能力骤增，反应速度和产率都因此有所提高。超临界酯交换不需要催化剂，但对设备要求相当高，且能耗较大。 在超临界基础上，加入少量催化剂可使酯交换反应有较高的速度和产率，而且大大降低了超临界反应的温度和压力，降低了能耗。 [ Last edited by feng2006 on 2009-8-14 at 15:18 ] |
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feng2006(金币+20,VIP+0):谢谢。还有两段啊，大家帮忙啊！ 8-14 16:32
feng2006(金币+15,VIP+0):再送你15个 谢谢了 8-14 17:30
feng2006(金币+20,VIP+0):谢谢。还有两段啊，大家帮忙啊！ 8-14 16:32
feng2006(金币+15,VIP+0):再送你15个 谢谢了 8-14 17:30
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influence of temperature and pressure The ester exchange reaction could happen at different temperatures for different raw materials. At normal pressures, a temperature of 60 C is suitable. Xiu Chen et al, reported a maximum yield of 94%for methyl ester at the optimal reaction temperature of 60 C for 1 hour using 1% NaOH as catalyst and at an alcohol/oil ratio of 6:1. If the reaction temperature increases further to approach or even exceed the boiling point of methanol, the methanol containing in the reation system would evaporate hugely to its vapor phase, leading to the decrease of methanol concentration in the liquid phase and then the decrease of reaction yield. |
2楼2009-08-14 15:51:49
pitlord999
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feng2006(金币+65,VIP+0):谢谢了。。。。。。 8-14 17:32
feng2006(金币+65,VIP+0):谢谢了。。。。。。 8-14 17:32
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剩下的两段 At critical conditions where the reaction temperature and pressure are around 239.4 oC and 8.09 MPa, i.e., the critical temperature and pressure of methanol, respectively [9], the super-critical condition of methanol is not ideal: its solution in ester is not high, and reaction rate and production rate are not fast. As pressure and temperature increases, the reaction rate and methyl ester production rate increase correspondingly, but a much higher temperature above the critical point of methanol would lead to side reactions such as pyrolysis and coking. Pressure has an obvious impact on the production rate of the ester exchange reaction. As the pressure increases, dielectric coefficient of methanol drops gradually to the same level as that of general organic solvent at the normal condition, exhibiting characteristics of nonpolar non-organic compounds, for instance, huge increase in solution rate of ester. As a result, the reaction rate and production rate also increase. Super-critical ester exchange is catalyst free, but has more requirements on equipment, and is more energy extensive. Base on the super-critical reaction, adding a small amount of catalyst could lead to higher reaction rate and production rate. Moreover, it could also greatly reduce the reaction temperature and pressure, thus reduce the energy consumption. |
3楼2009-08-14 17:19:03