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1.
以乙酸和异戊酸为原料,采用硫酸氢钠为催化剂合成了乙酸异戊酯,当反应时间为1h,醇酸物质的量比为1:3,催化剂用量为醇酸总量的3.0%,反应温度为130~135℃,酯的产率可达85%以上。  相似文献   

2.
以固体超强酸树脂为酯化催化剂合成了戊二酸二丁酯,考察了醇酸摩尔比、带水剂用量、催化剂用量及反应时间对酯化率的影响,通过极差分析,确定了合成戊二酸二丁酯的优化反应条件:以0.25mol戊二酸二丁酯为基准,醇酸摩尔比为3.0,催化剂用量为0.6%,带水剂环己烷24ml,反应时间为90min,戊二酸二丁酯收率可达99.3%以上。  相似文献   

3.
对甲苯磺酸催化合成异丁酸丁酯   总被引:7,自引:0,他引:7  
以对甲苯磺酸为催化剂催化合成了异丁酸丁酯,确定了酯化优化条件。实验结果表明,最佳反应条件是:醇酸摩尔比为1.4:1.0,异丁酸用量为0.1mol的情况下,催化剂用量为0.5g,带水剂苯为5mL,反应时间2.0h,反应温度为108℃~124℃,精酯的收率达到92.4%。  相似文献   

4.
固体超强酸TiO2/SO2-4催化合成乙酸戊酯的研究   总被引:2,自引:0,他引:2  
对以固体超强酸TiO2/SO^2-4为催化剂,冰醋酸和戊醇为原料,催化合成乙酸戊酯的反应进行了研究,探讨了催化剂用量、醇酸比、反应时间等对酯化反应的影响。结果表明:醇酸摩尔比为1:3,催化剂用量为1.5g,反应时间为1.5h,酯的产率达94.6%。  相似文献   

5.
以柠檬酸和正丁醇为原料,钛酸四丁酯为催化剂合成柠檬酸三丁酯,用单因素分析法研究醇酸摩尔比、催化剂用量、反应时间及反应温度对酯化反应的影响。结果表明,酯化反应的最佳条件为:n(醇):n(酸):3.6:1.0,催化剂用量为柠檬酸质量的0.40%,反应时间4h,反应温度130~140℃,酯化率达到94.51%,纯度大于99.1%。  相似文献   

6.
以四氯化锡为催化剂,正丁酸和正戊醇为原料合成了丁酸戊酯,并考察了影响该酯化反应的诸因素。结果表明:催化剂用量为反应物总量的3.0%,醇酸摩尔比为1.30:1,反应时间为60min,酯收率可达93.6%。  相似文献   

7.
研究了以氨基磺酸为催化剂,苯甲酸和乙醇为原料合成苯甲酸乙酯,并考察了影响反应的因素。结果表明,醇酸摩尔比为8:1,催化剂用量为3.0g(苯甲酸以50mmol计),反应时间为8.0h是最适宜的反应条件,酯产率达87.4%。  相似文献   

8.
TiSiW12O40/TiO2催化合成乳酸正丁酯   总被引:10,自引:2,他引:8  
报道了新型催化剂TiSiW12O40/TiO2的制备方法,实验考察了该催化剂催化酯化合成乳酸正丁酯的醇酸比、催化剂用量、带水剂、反应时间等因素对酯收率的影响。实验表明,在以苯为带水剂时,催化剂的用量为总反应物质量的1.3%,醇酸摩尔比为2.0:1,酯化反应时间为110min,乳酸正丁酯的收率达95%。  相似文献   

9.
H3PW12O40/SiO2催化合成季戊四醇四庚酸酯的研究   总被引:1,自引:0,他引:1  
以正硅酸乙酯为硅源,采用溶胶-凝胶法制备硅载磷钨酸催化合成了季戊四醇四庚酸酯.考察了催化剂用量、醇酸摩尔比、反应温度、反应时间以及催化剂重复使用对酯含量的影响.实验表明,在催化剂用量(质量分数)为总体系的2%、醇酸摩尔比1:6、反应温度120℃~200℃、反应时间4h的条件下,酯化率可达96%以上,且催化剂重复使用效果好.  相似文献   

10.
硫酸-石墨层间化合物催化合成丙酸戊酯的研究   总被引:5,自引:0,他引:5  
研究了硫酸-石墨层间化合物催化丙酸与戊醇的酯化反应,探讨了催化剂用量、反应时间及醇、酸摩尔比对酯产率的影响。当醇、酸摩尔比为0.1:0.2,催化剂量为醇酸总质量的3.7%,反应时间为40min时,酯产率可高达95.6%以上。  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.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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   

16.
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   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
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