稀土固体超强酸SO2-4/TiO2/La3+催化合成丁酸乙酯

研究了以固体超强酸ＳＯ４＾２－／ＴｉＯ２／Ｌａ＾３＋为催化剂,丁酸和无水乙醇为原料合成丁酸乙酯,并考察了影响反应的因素。结果表明,醇酸摩尔比为２．０：１,催化剂用量的０．５ｇ（丁酸为０．２ｍｏｌ的情况下）,带水剂苯为１５ｍＬ,反应时间为２．０ｈ,是最适宜的反应条件,酯化率达９５．６％。     

稀土固体超强酸SO42-/TiO2/La3+催化合成马来酸二戊酯

研究了以固体超强酸ＳＯ４＾２－／ＴｉＯ２／Ｌａ＾３＋为催化剂,马来酸和正戊醇为原料合成马来酸二戊酯并考察了影响反应的因素。结果表明,醇酸摩尔比为４．０：１,催化剂用量为１．０ｇ,带水剂甲苯为１５ｍＬ,反应时间为３．０ｈ是最适宜的反应条件,酯化率达９８．８％。     

稀土固体超强酸SO^2—4／TiO2／La^3＋催化合成异丁酸丁酯

研究了以稀土固体超强酸ＳＯ＾２－４／ＴｉＯ２／Ｌａ＾３＋为催化剂，异丁酸和正丁醇为原料合成异丁酸丁酯，并考察了影响反应的因素。结果表明，醇酸比为１．８１：１，催化剂用量为０．５ｇ，带水剂甲苯为１５ｍｌ，反应时间为２．０ｈ是最适宜的反应条件，酯化率达９７．２％。     

稀土固体超强酸SO^2—4／TiO2／La^3＋催化合成马来酸二丁酯

以固体超强酸ＳＯ＾２－４／ＴｉＯ２／Ｌａ＾３＋为催化剂,马来酸和正丁醇为原料合成马来酸二丁酯,考察了影响反应的因素,结果表明：ｎ（醇）：ｎ（酸）＝４．０：１,催化剂用量为１．０ｇ;带水剂甲苯为１５ｍＬ;反应时间为３．０ｈ是最的反应条件,酯化率达９７．４％。     

稀土固体超强酸SO4^2—／TiO2／La^3＋催化合成丁酸丁酯

研究了以稀土固体超强酸ＳＯ４＾２－／ＴｉＯ２／Ｌａ＾３＋为催化剂,丁酸和正丁醇为原料合成丁酸丁酯,并考察了影响反应４ 因素。结果表明,醇酸物质的量比为１．８：１,催化剂用量为０．５ｇ（本酸为０．２ｍｏｌ的情况下）,带水剂甲苯为１５ｍＬ,反应时间为２．０ｈ是合成丁酸丁酯的较适宜的反应条件,酯化率达９８．６％。     

固体超强酸SO4^2—／ZrO2—TiO2催化剂的研制及其催化合成草莓酸酯的 …

选用ＳＯ４＾２－／ＭｘＯｙ型固体超强酸催化草莓酸的酯化反应,筛选出催化剂ＳＯ４＾２－／ＺｒＯ２－ＴｉＯ２,制备该催化剂的最优条件为：钛锆物质的量比为４：１,氨水调节ｐＨ值８～９,用浓度为０．５ｍｏｌ／Ｌ硫酸浸渍,马弗炉５５０℃焙烧３ｈ;使用该仙化剂合成草莓酸酯的最优酯化条件为：催化剂用量３ｇ／ｍｏｌ,酯化时间３ｈ,其催化合成草莓酯戊酯产率可达９０．８％。     

TiSiW12 O40/Ti2催化合成葡萄糖五丁酸酯

报道了新型催化剂ＴｉＳｉＷ１２Ｏ４０／ＴｉＯ２催化酯化合成工区２糖五丁酸酯的糖酸比、催化剂用量、反应时间、反应温度诸因素对产率的影响。实验表明：ＴｉＳｉＷ１２Ｏ４０／ＴｉＯ２是合成葡萄糖五丁酸酯的良好催化剂,最佳反应条件为：糖酸摩尔比１：６,催化剂的用量为反应物料总量的２．０％,酯化反应时间为２．０ｈ,反应温度９０￣９５℃,反应产率可达８５．４％。     

稀土改性SO^2—4／TiO2催化合成尼泊金酯

以稀土改性的固体超强酸ＳＯ＾２－４／ＴｉＯ２为催化剂，无水ＭｇＳＯ４作脱水剂，合成了尼泊金丁酯。考察了影响收率的诸因素，其最佳条件为：醇酸摩尔比为３：１，催化剂用量２０ｇ／ｍｏｌ酸，回流温度下反应３．０ｈ，收率达到９０．４％。     

稀土固体超强酸SO_4~(2-)/TiO_2/La~(3 )催化合成异丁酸丁酯

研究了以稀土固体超强酸 ＳＯ_４~（２－）／ＴｉＯ_２／Ｌａ~（３＋）为催化剂，异丁酸和正丁醇为原料合成异丁酸丁酯，并考察了影响反应的因素。结果表明，醇酸比为 １． ８∶ １，催化剂用量为 ０． ５ｇ，带水剂甲苯为 １５ｍｌ（异丁酸为 ０．２ｍｏｌ的情况下），反应时间为 ２．０ｈ是最适宜的反应条件，酯化率达９７． ２％。     

固体超强酸SO4^2—／ZrO2催化合成对羟基苯甲酸乙酯

以固体超强酸ＳＯ４＾２－／ＺｒＯ２为催化剂合成了对羟基苯甲酸乙酯，并研究了催化剂等条件对反应的影响，在最佳反应条件下，酯收率达到８０．１％。     

Self-organized nano-crystallisation of BaF2 from Na2O/K2O/BaF2/Al2O3/SiO2 glasses

In glasses with the compositions (100 ? x)(2Na₂O·16K₂O·8Al₂O₃·74SiO₂)xBaF₂ (with x = 0 to 6), the glass transition temperature decreases with increasing BaF₂-concentration. Samples with x = 6 were thermally treated at temperatures in the range from 500 to 600 °C for 5–160 h. This leads to the crystallisation of BaF₂. The quantity of crystalline BaF₂ increases with increasing time of thermal treatment, while the mean crystallite size remains constant within the limits of error. The glass transformation temperature of partially crystallised samples increases with increasing crystallisation time and approaches a value equal to the temperature, at which the samples were treated. This is explained by the formation of a highly viscous layer enriched in SiO₂ which is formed during crystallisation. This layer acts as a diffusion barrier and hinders further crystal growth.     

复合固体超强酸SO42-/ZrO2-Al2O3催化合成乳酸正丁酯的研究

合成了几种不同Zr、Al原子比的SO42-/ZrO2-Al2O3复合固体超强酸,将其用于催化乳酸与正丁醇的酯化反应,均有较好的催化活性,尤以ZrAl=12的催化效果最好,经济性优于ZrO2超强酸催化剂.其最佳反应条件为酸醇摩尔比为13,催化剂用量为乳酸质量的10%,反应时间2～2.5h,酯化率达96.9%.该催化剂具有制备容易、催化活性高、不污染环境、可重复使用的优点.     

The System Na2O-CaO-SiO2-H2O

A portion of the quaternary phase diagram for Na₂O-CaO-SiO₂-H₂O has been constructed. Plotting concentrations as their 10th roots allows compounds having solubilities which differ by several orders of magnitude to be represented on a single diagram. The compositional relationships among sodium-substituted calcium silicate hydrate, calcium-substituted sodium silicate hydrate, calcium bydroxide, a quaternary compound of approximate composition 0.25Na₂O · CaO · SiO₂· 3H₂O, sodium hydroxide monohydrate, and miscellaneous sodium silicate hydrates are presented. The quaternary diagram constructed shows the quaternary compound to exist in equilibrium with sodium-substituted calcium silicate hydrate and calcium hydroxide. Conditions in concrete pore solutions which favor the formation of this quaternary compound may also favor the occurrence of the alkali-silica reaction.     

Prediction of Immiscibility Boundaries of the Systems K2O-SiO2, K2O-Li20-SiO2, K20-Na2O-Si02, and K2O-BaO-SiO2

In earlier work, a prediction method of the immiscibility boundary of a ternary silicate glass system was developed involving two known binary immiscibility boundaries and a measured immiscibility temperature of one ternary glass composition. In the present work, the method is extended to the case where one of the two binary immiscibility boundaries is not known and is applied as an example to ternary silicate systems containing K₂O. First, the immiscibility boundary of the system K₂O-SiO₂ is estimated by measuring the immiscibility temperatures of three glasses in the system K₂O-Li₂O (or Na₂O)-SiO₂. Using this result the immiscibility boundaries of the systems K₂O-Li₂O-SiO₂, K₂O-Na₂O-SiO₂, and K₂O-BaO-SiO₂ are estimated. The results agree reasonably well with the experimentally determined immiscibility temperatures at selected compositions.     

Some Properties of the System Na2O-NaF-B2O2-H2O

It was first shown that the enamel slips which have the best suspnding characteristics contain equal amounts of Na₂O and B₂O₃ and at least a moderate amount of NaF. The solubilities of mixtures of Na₂O, NaF, and B₂O₃ were then investigated. The pH of these solutions and the primary crystalline phases separating on evaporation also were determined. The solubility data obtained at room temperature were summarized. When the solutions were evaporated, NaF was the first crystalline phase to separate from a large proportion of the mixtures investigated. It was concluded that the desirable handling characteristics of enamels whose mill liquors contain the proper proportion of Na₂O, NaF, and B₂O₃ are not due to the formation of complex salts but to the following combination of properties: (1) the presence of salts with a moderate solubility which changes very slightly with temperature, (2) a moderate pH of about 10 in a probably well-buffered solution, (3) a relatively stable crystalline material, NaF, as a primary phase, and (4) a secondary phase which crystallizes slowly with relatively little shrinkage.     

固体超强酸SO^2—4／TiO2催化合成尿囊素的研究

用固体超强酸SO42/TiO2为催化剂,以尿素和乙醛酸为原料合成了尿囊素。得到最佳条件为TiO2在1mo1·L-1H2SO4溶液中浸渍12h,再在600℃焙烧3h;尿素与乙醛酸摩尔比3.51,催化剂9％,时间3h,温度72℃～75℃,产率达57.4％。     

Photocatalytic activity of Cu2O/TiO2, Bi2O3/TiO2 and ZnMn2O4/TiO2 heterojunctions

Cu₂O/TiO₂, Bi₂O₃/TiO₂ and ZnMn₂O₄/TiO₂ heterojunctions were studied for potential applications in water decontamination technology and their capacity to induce an oxidation process under VIS light. UV–vis spectroscopy analysis showed that the junctions-based Cu₂O, Bi₂O₃ and ZnMn₂O₄ are able to absorb a large part of visible light (respectively, up to 650, 460 and 1000 nm). This fact was confirmed in the case of Cu₂O/TiO₂ and Bi₂O₃/TiO₂ by photocatalytic experiments performed under visible light. A part of the charge recombination that can take place when both semiconductors are excited was observed when a photocatalytic experiment was performed under UV–vis illumination. Orange II, 4-hydroxybenzoic and benzamide were used as pollutants in the experiment. Photoactivity of the junctions was found to be strongly dependent on the substrate. The different phenomena that were observed in each case are discussed.     

Phase Diagrams for the Systems MgCl2-MgF2, CaCl2-MgF2, and NaCl-MgF2

Equilibrium phase diagrams for the systems MgCl₂-MgF₂, CaCl₂-MgF₂ and NaCl-MgF₂ were determined by differential thermal analysis, thermal analysis, and temperature-composition equilibrium techniques. Simple eutectics were observed at 78.0±0.5 mol% MgCl₂ and 628°±2°C in the MgCl₂-MgF₂ system, at 87.5±0.5 mol% CaCl₂ and 694°±2°C in the CaCl₂-MgF₂ system, and at 95.5±0.5 mol% NaCl and 786°±3°C in the NaCl-MgF₂ system. The phase diagrams determined for these systems were compared with phase diagrams that were computed using Temkin's model. The phase diagrams of the CaCl₂-MgF₂ and NaCl-MgF₂ systems were also compared with diagrams that were computed using the expression suggested by Flood et al. for reciprocal systems. The experimentally determined and computed phase diagrams agreed for the MgCl₂-MgF₂ system but not for the CaCl₂-MgF₂ and NaCl-MgF₂ systems.     

Crystallization of zeolite L from Na2O-K2O-Al2O3-SiO2-H2O system

Zeolite L powder was prepared from the substrate mixture of Na₂O-K₂O-Al₂O₃-SiO₂-H₂O system at temperatures of 373-443 K. In order to investigate the factors which influence the synthesis outcome, a reference system which yields zeolite L in a reproducible manner was chosen and subjected to controlled changes in synthesis parameters. The crystalline zeolite L samples obtained were characterized by elemental chemical analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). It was established that phase purity, morphology, and the size of crystals of crystalline product were affected by molar ratios of the substrate, such as SiO₂/Al₂O₃, (K₂O+Na₂O)/SiO₂, Na₂O/(K₂O+Na₂O), and H₂O/(K₂O+Na₂O). Amorphous silica powder (Zeosil) was the preferred silica source, and the crystallization rate was promoted by introducing gel aging, seeding, and rapid heating rate.