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1.
以四氯化硅、苯酚和环氧氯丙烷为原料,合成一种硅卤协同阻燃增塑剂硅酸三(二氯丙基)苯酯.用正交试验探讨反应物质的量比,反应温度以及反应时间等对产率的影响,筛选出最适宜的工艺条件为四氯化硅与苯酚的物质的量比为1∶1,四氯化硅与环氧氯丙烷的物质的量比为1∶3.3,反应温度为90℃,反应时间为8h,产率为98.2%.并采用FT...  相似文献   

2.
以活性炭负载硫酸钛作为催化剂,冰乙酸和异戊醇为原料合成乙酸异戊酯,研究了影响反应的各种因素.结果表明,当冰乙酸和异戊醇的物质的量比为2.5∶1,催化剂中Ti SO4 2与活性炭的质量比为3∶1,反应时间2.5 h,反应温度为120℃时,酯化率可达到93.86%.  相似文献   

3.
用金属氯化物做催化剂,碱金属卤化物做助剂,催化葡萄糖脱水制备5-羟甲基糠醛(5-HMF).在原料与催化剂的质量比为10∶1,原料与助催化剂的质量比为1∶1的情况下,考察金属氯化物、助剂、溶剂、温度、时间对5-HMF收率的影响.结果显示:Al Cl3做催化剂、Na I做助剂、溶剂为N,N-二甲基乙酰胺(DMAC)、反应温度为130℃、反应时间为15 min时5-HMF收率可达30.6%.  相似文献   

4.
H_4PMo_(11)VO_(40)催化氧化2-甲基萘制备甲萘醌   总被引:1,自引:1,他引:0  
以磷钼钒杂多酸H4PMo11V1O40为催化剂、乙酸为溶剂,用双氧水氧化2-甲基萘制备2-甲基萘醌.实验表明:H4PMo11V1O40具有一定的催化活性.通过正交试验和单因素试验考察了催化剂用量、乙酸用量、双氧水用量、反应时间、反应温度等对收率的影响,获得较佳的合成条件:杂多酸∶2-MN(质量比)=7%,乙酸∶2-MN(质量比)=10.5∶1,双氧水∶2-甲基萘(摩尔比)=4.2∶1,较适宜的温度为40~50℃,反应时间为30 min.  相似文献   

5.
以二苯乙醇酸为原料合成9-芴甲酸,探讨了反应时间、反应温度、催化剂的种类和用量、溶剂的种类和用量等因素对产物收率的影响,并对产物进行了红外吸收、HPLC和核磁共振表征。最佳合成条件为:反应时间2.5 h,原料与溶剂的质量比为1∶13,原料和催化剂的物质的量的比为1∶3,反应温度控制在回流状态下。  相似文献   

6.
探讨了反应温度、反应时间、催化剂及其用量和溶剂(环氧氯丙烷)用量等主要制备工艺条件对单体转化率的影响.以甲基丙烯酸和环氧氯丙烷为原料,十六烷基三甲基溴化铵为相转移催化剂,制备了无甲醛交联性单体甲基丙烯酸缩水甘油酯.研究结果表明,在最佳制备工艺条件下(催化剂对甲基丙烯酸钠质量百分数5.5%、反应温度95~100℃、反应时间150~160min、环氧氯丙烷与甲基丙烯酸钠的摩尔比为5.5:1.0),甲基丙烯酸钠盐的转化率接近95%,产物的纯度大于96%.  相似文献   

7.
本文研究了合成N-甲基哌嗪的新方法.即以二乙醇胺和甲胺为原料,选用不同类型催化剂,通过固定床反应器,气固相催化环合制取N-甲基哌嗪的方法.并对反应温度、压力、物料配比等因素对反应的影响作了系统的研究.确定了该环合反应所用最佳催化剂为硅铝比为30的HZSM-5型分子筛催化剂,最佳反应条件为反应温度为300℃,操作压力为8 MPa,二乙醇胺和甲胺的物质的量比为1∶2,空速为0.5 L./h.在此条件下,N-甲基哌嗪的收率可达80%以上,选择性可达90%.  相似文献   

8.
在固定床反应器中,以自制挤条成型的ZSM-5型含钛(TS-1)分子筛为催化剂,采用丙烯气相进料,并预先与双氧水的甲醇溶液混合,系统考察了液体空速、丙烯与过氧化氢摩尔比、反应温度、双氧水甲醇混合溶液中双氧水浓度以及水含量等工艺条件对丙烯直接环氧化连续反应的影响。结果表明:当反应压力为0.7MPa,反应温度为50℃,进料中wH2O2=0.015,进料液体的质量空速为48h-1时,双氧水的转化率和环氧丙烷的选择性分别在90%和85%以上。  相似文献   

9.
采用逐级优化的单因素实验考察钛硅-1分子筛(TS-1)催化丙酮氨氧化合成丙酮肟的反应条件.结果表明:催化剂用量、氨酮摩尔比、氧酮摩尔比、氨水及双氧水滴加时间、氨水及双氧水滴加组合模式、叔丁醇与水体积比及反应温度等因素对反应效果影响较显著.适宜的反应条件为:每mol丙酮催化剂用量4g以上,氨酮摩尔比2.0以上,氧酮摩尔比1.0~1.4,氨水及双氧水滴加时间不小于1 h,且同时滴加完毕,后续反应时间不小于1h,V(叔丁醇)/V(水)=2.3,反应温度70 ℃.在此优化反应条件下,丙酮转化率可达95%,丙酮肟选择性为98%.  相似文献   

10.
钛硅分子筛催化苯乙烯氧化制苯甲醛   总被引:5,自引:0,他引:5  
将采用四丙基溴化铵(TPABr)为模板剂、硅溶胶为硅源合成的钛硅分子筛TS-1用于苯乙烯氧化反应。与采用经典法合成的TS-1相比,采用廉价原料合成的TS-1在苯乙烯氧化反应中的活性较低,但苯甲醛选择性高。钛硅分子筛中的骨架钛物种催化苯乙烯转化为苯乙醛,而部分缩合六配位钛物种催化苯乙烯转化成苯甲醛。与丙酮做溶剂相比,苯乙烯氧化反应选用醇类溶剂苯甲醛选择性高,其中,甲醇做溶剂时反应结果最好。V(甲醇)/V(苯乙烯)=3时,苯乙烯转化率最高,采用廉价原料合成的TS-1催化苯乙烯氧化制得的苯甲醛不含氯,可用于食品工业。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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