Rates of carbonate bond formation: Implications for macrocyclization

High yields of cyclic oligomeric carbonates can be prepared using an amine-catalyzed reaction of bisphenol A–bischloroformate. We have studied the mechanistic aspets of this carbonate macrocyclization by the isolated study of key chemical events. Using stopped-flow FT-IR spectroscopy, we have found that the rate of carbonate formation between the intermediate acyl ammonium salt and 4-isopropylphenol is the same for the acyl ammonium salt derived from tri-n-butylamine, triethylamine and diethylmethylamine. Previously, we found that conversion of acyl ammonium salt to urethane was also insensitive to amine structure while the formation of acyl ammonium salt is profoundly dependent on amine structure. These results are consistent with a mechanism in which the selectivity toward macrocyclization versus linear oligomer or high polymer formation is related to acyl ammonium salt concentration.     

Lewis酸、碱催化碳酸二甲酯与苯酚酯交换反应

研究了几种Lewis酸、碱作催化剂对碳酸二甲酯与苯酚的酯交换反应催化活性 ,其中Pb(Ac) 2 ·3H2 O具有较高的催化活性和选择性。以Pb(Ac) 2 ·3H2 O为催化剂对反应的催化剂用量、原料配比、反应温度和反应时间等工艺条件进行了研究。实验表明 :当n(碳酸二甲酯 )∶n(苯酚 )∶n(Pb(Ac) 2 ·3H2 O) =1∶4∶0 0 4,反应温度 175℃ ,反应时间15h时 ,酯交换反应基本上达到平衡 ,苯酚的转化率为 2 4 80 % ,MPC的选择性为 76 49% ,DPC的选择性为2 3 5 1%     

阿克库勒凸起奥陶系控油地质特征

阿克库勒凸起位于塔里木盆地沙雅隆起中段的南翼，奥陶系碳酸盐岩具有广阔的油气勘探前景，但受区域构造背景及储集体发育程度控制明显，油气分布不均，通过奥陶系油气藏类型及其分布，控油地质特征等方面分析，并预测了奥陶系油气藏有利成藏分布范围，认为阿克库勒凸起南部斜坡区的岩溶潜丘与强变形地带发育，并保留了有效的储集体和存在多期次的油气运聚成藏，封盖条件较好，是形成大型油气藏的有利部位。     

Improvement in the Microbiological Quality of Ready-To-Use Desalted Cod

ABSTRACT: To reduce the microbial load of ready-to-use desalted cod, 2 different concentrations of sodium chloride (3.13% and 5.78% in water phase), potassium sorbate (0.14% and 0.20% in water phase), and citric acid (pH 6.10 and 5.77), with 2 kinds of packaging procedures (air or vacuum), have been used. The vacuum packaging was effective only in the samples with 3.13% salt after 28 d of storage, whereas no important differences between both packaging procedures were observed in samples with 5.78% salt. This last salt level only limited the Pseudomonas growth, however it was necessary to combine this salt concentration with potassium sorbate plus citric acid to inhibit mesophilic, psychrotrophic, and molds and yeasts.     

临盘油田临95断块成岩作用研究

通过对临95断块沙一段、沙二段储层岩性、储层物性与沉积微相分布的关系、成岩作用的类型及成岩作用对储层物性的控制因素研究．认为不同沉积微相下的成岩作用差别造成储层物性的差异，并指出碳酸盐胶结怍用是该区储层变差的主要原因，颗粒周围的粘土薄膜是抑制碳酸盐的胶结、导致储层物性好的重要因素。     

In situ FTIR spectra at the Cu electrode/propylene carbonate solution interface

In situ Fourier transform infrared spectroscopy (FTIR) spectra measurements were obtained for a Cu electrode/solution of lithium perchlorate in propylene carbonate (PC). The dependence of potential on the concentration of PC in the vicinity of the electrode was investigated. The bands due to free PC and PC solvated to lithium ions in the solution were distinguished by the single reflection attenuated total reflection (ATR) spectra. In the FTIR spectra, the reversible change in the concentration of free PC and solvated PC in the diffuse double layer was observed to be accompanied by a change in potential. As the potential decreased, the free PC concentration increased, while the concentration of the PC solvated to lithium ions decreased. Thus, it can be concluded that the equilibrium shifts from Li⁺(PC)₄ to Li⁺(PC)₃ + PC as the potential decreases. Furthermore, Li⁺(PC)₃ orientates itself so that it is parallel to the electrode surface.     

松南20丛式井组钻井完井液技术

根据松南地区后五家户构造气藏储层特点和直井钻井经验，首次选择了适合丛式钻井的ＰＫＺ－Ｉ型屏蔽暂堵式钾聚合物钻井完井液体系。经松南２０丛式井组的５口定向井验证，该体系具有良好的润滑性、防塌性、滤失性及携岩能力，有利于保护储层和提高钻速，效益显著     

南海石炭系潜山储层特征及地震识别

南海某盆地A凹陷基底石炭系碳酸盐岩遭受了二叠纪-白垩纪期间漫长地质时期的风化和侵蚀，发育了大量的优质碳酸盐岩岩溶型储集层。但碳酸盐岩潜山岩溶型储层发育的复杂性，一直制约着对其进一步的勘探。为此，通过对岩溶型储集层的划分对比，认为该区岩溶型储集层可以划分为表层岩溶带、渗流岩溶带和潜流岩溶带；其储集层主要以溶蚀孔洞、洞穴以及构造裂缝组成，其中溶蚀孔洞、洞穴是主要的储集空间，构造裂缝主要起着连通基质孔隙、溶蚀孔洞、洞穴和改善储集层渗滤条件的作用。利用钻井资料对岩溶型储集层进行标定后，认为表层岩溶储集层为弱振幅、弱连续（低相干）和低阻抗的特征，内幕储集层则为短轴状强振幅、高能量和低阻抗的特征，能够利用地震属性对岩溶型储集层进行识别。     

Viscosity and thermal conductivity of binary eutectics of alkali metals in the vapor phase

Values calculated for the dynamic viscosity and thermal conductivity are presented for vapors of binary eutectics of the alkali metals at temperatures from 800 to 1500 K and at pressures from 100 to 8×10⁵ Pa. Data are presented for the vapors of the systems Li + Na, Na + Rb, Na + Cs, K + Rb, K + Cs, Na + K, and Rb + Cs. The values of the concentrations of the five components in the vapor phase of each binary eutectic are also presented. The accuracy of the calculated viscosities is estimated to be within 4–5% and the accuracy of the calculated thermal conductivities is estimated to be within 8–10%.     

On the texturization of monocrystalline silicon with sodium carbonate solutions

The texturization of monocrystalline silicon wafers using sodium carbonate solution has been investigated. This etching process has been evaluated in terms of the surface morphology and the reflectance value. The results show that for low concentration of sodium carbonate the increase of texturing time decreases the reflectance value because of the change in morphology from hillocks to pyramidal; on the contrary for intermediate and high concentrations the increase of time has a detrimental effect on texturization because it increases both the pyramid sizes and their non-uniform distribution. However, a good cell performance could be obtained by etching at high concentrations and short times.