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1.
以碳酸钾作为催化剂,异辛醇与碳酸甲辛酯催化酯交换-吸附法合成碳酸二异辛酯。考察了醇酯比、催化剂用量和反应时间等因素对反应的影响。通过实验得到适宜工艺条件为催化剂用量为5%,醇酯比为4∶1,温度控制在160~170℃条件下反应时间为2 h,产品碳酸二异辛酯产率为47.2%,采用气相色谱分析质量纯度99.1%。催化剂重复使用4次时,催化活性没有明显的降低。  相似文献   

2.
 乙烯裂解生产过程中存在的一个突出问题是结焦,在裂解原料中添加抑制剂是抑制结焦的一种重要方法,磷酸二异辛酯的吗啉盐是一种新型的结焦抑制剂。本实验以磷酸和异辛醇为原料,分别以活性氧化铝、活性硫酸钠、钨磷酸为催化剂,合成磷酸二异辛酯。通过改变催化剂的种类,选择催化性能良好的杂多酸钨磷酸为催化剂。实验结果表明,反应条件对目标产物收率有很大影响,钨磷酸含量为5%,催化剂用量为原料质量的2.0%,异辛醇与磷酸的物质的量之比为2.3,反应时间为4h时,磷酸二异辛酯收率最高,达72.8%。IR谱图分析结果表明产物为目标产物磷酸二异辛酯。  相似文献   

3.
以碳酸二甲酯和异辛醇为原料,碳酸钾为催化剂,采用酯交换-吸附联合工艺合成甲基异辛基碳酸酯。考察了原料配比、催化剂用量、反应时间对反应过程的影响。通过实验得到适宜的工艺条件为原料摩尔比为3∶1,催化剂用量为5%,沸腾温度下反应时间为3 h,产品产率达到97.30%。通过红外光谱分析,产物为甲基异辛基碳酸酯。  相似文献   

4.
在以顺丁烯二酸和异辛醇为原料,用DMAP/DCC催化合成顺丁烯二酸二异辛酯的实验中,考察了对甲苯磺酸、浓硫酸和N,N-二环己基碳酰亚胺(DCC)、4-二甲氨基吡啶(DMAP)等几种催化剂的催化性能.结果表明,在室温条件下DCC/DMAP的催化活性高,是一种比较好的酯化反应催化剂.同时考察了反应时间、醇酸比、催化剂用量、反应温度对合成顺丁烯二酸二异辛酯收率的影响.实验结果表明,当反应时间为4h,异辛醇与顺丁烯二酸的物质的量之比为2.2:1(mol/mol),反应温度为20℃时,顺丁烯二酸二异辛酯的收率可达到91.3%.  相似文献   

5.
以顺丁烯二酸酐和异辛醇为原料,用一种高活性的固体超强酸S O24-/SnO 2催化剂催化合成了顺丁烯二酸二异辛酯,研究了酯化反应的优化条件。当n(异辛醇):n(顺丁烯二酸酐)为2.8:1;催化剂用量为酐质量的1.0%时,反应时间120 min,反应温度145℃,顺丁烯二酸二异辛酯的收率达到98.7%。同时对用H2SO4和对甲苯磺酸催化该反应作了比较。  相似文献   

6.
邻苯二甲酸二异辛酯和邻苯二甲酸二正辛酯的合成   总被引:4,自引:0,他引:4  
采用对甲苯磺酸作催化剂合成了邻苯二甲酸二异辛酯(DOP)和邻苯二甲酸二正辛酯(DnOP),探讨了原料配比、催化剂用量、反应时间及带水剂对酯化产率的影响,并确定了最佳工艺条件.研究结果表明,当邻苯二甲酸、异辛醇、对甲苯磺酸的摩尔比为1∶3∶0.125,带水剂甲苯10 ml,反应时间1.5 h时,酯收率可达97.43%;当邻苯二甲酸、正辛醇、对甲苯磺酸的摩尔比为1∶2.5∶0.142,带水剂甲苯10 ml,反应时间1.5 h时,酯收率可达98.46%.  相似文献   

7.
固载杂多酸催化合成戊二酸二异辛酯   总被引:2,自引:0,他引:2  
研究了活性碳固载杂多酸催化戊二酸和异辛醇合成戊二酸二异辛酯的反应 ,探讨了原料配比 ,反应时间 ,催化剂用量等参数对酯化率的影响 ,在适宜工艺条件下 ,酯化率可达96.8 %  相似文献   

8.
以顺丁烯二酸酐和异辛醇为原料,用一种高活性的固体超强酸SO4^2-/SnO2催化剂催化合成了顺丁烯二酸二异辛酯,研究了酯化反应的优化条件。当n(异辛醇):n(顺丁烯二酸酐)为2.8:1;催化剂用量为酐质量的1.0%时,反应时间120min,反应温度145℃,顺丁烯二酸二异辛酯的收率达到98.7%。同时对用H2SO4和对甲革磺酸催化该反应作了比较。  相似文献   

9.
将介孔材料SBA-15与磷钨酸溶液在80℃水浴条件下蒸发浓缩制备负载型磷钨酸催化剂HPW-SBA-15作为合成癸二酸二辛酯的催化剂,并分析其酸催化性能及磷钨酸的负载量、温度、反应时间、酸醇比等因素对合成癸二酸二辛酯的影响.结果表明,在催化合成癸二酸二辛酯时,最佳反应条件为:磷钨酸负载量为50%,反应时间为2.5h,n(癸二酸)∶n(异辛醇)=1∶3.此时,酯化率最高为95.47%.  相似文献   

10.
制备固体超强酸Fe_2O_3-SO_4~(2-)催化壬二酸和2-乙基己醇合成了壬二酸二辛酯.通过实验对催化剂种类、催化剂用量、壬二酸和2-乙基己醇物质的量比、反应温度和反应时间进行对比,研究各实验因素对合成壬二酸二辛酯产率的影响.经过实验优化,当催化剂固体超强酸Fe_2O_3-SO_4~(2-)用量为壬二酸质量的0.4%、壬二酸和2-乙基己醇物质的量比为1:3、反应温度为210℃、反应时间为2.5 h时,壬二酸二辛酯产率可达97.2%.该催化剂经过5次循环使用后,壬二酸二辛酯的产率仍可达到88.7%,具有较好的催化活性和稳定性.  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.
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.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

16.
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   

17.
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   

18.
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   

19.
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   

20.
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   

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