红壤性水稻土可溶态稀土分布特征及与酸度调控的关系

测定了具有代表性的4种母质发育、3种水育型的红壤性水稻土及起源土壤的可溶性稀土(REEs)和稀土总丰度(∑REE),分析了REEs的分布特征及与∑REE的相关,研究了经酸碱调节后土壤REEs与pH值的关系,结果表明:(1)不同母质发育的供试土壤REEs平均值依石英闪长岩母质土壤系列、凝灰岩母质土壤系列、黑云母花岗岩母质土壤系列、玄武岩母质土壤系列顺序递减。(2)供试土壤REEs与∑REE的相关不显著。(3)起源土壤剖面中REEs具有明显自上而下增大的趋势,而不同水育型水稻土剖面的REEs分布各有特征,但总的趋势是自上而下减少。(4)经酸度调节后供试土壤的REEs随着土壤pH值的提高而下降,呈显著的幂函数相关。     

提高羧甲基纤维素钠酸黏比的研究

以乙醇为溶剂,精棉、氯乙酸和氢氧化钠为原料,加入价廉的、对人体无害的添加剂来加深碱化与醚化反应的深度,可制备出高酸黏比(小试达1.00左右)的羧甲基纤维素钠(CMC)。运用数理统计与正交试验法研究了物料配比、添加剂种类与用量、反应温度、反应时间以及其它强化碱化与醚化深度的多种因素,从而确定了提高CMC酸黏比的优化反应条件,为中试与扩大试验提供了参考的依据。     

水蒸气处理对渣油加氢催化剂性质的影响

研究了水蒸气处理对渣油加氢催化剂载体性质的影响。结果表明处理时间、空速及焙烧温度对催化剂载体的孔结构和表面酸度均有显著影响;与在空气中焙烧相比,在有水蒸气存在的条件下焙烧,载体的相对酸度由1.000下降为0.491~0.884,相对比表面积由100下降为66~79,相对孔容由1.00上升为1.13~1.22,相对孔径由1.0上升为1.3~1.9。     

Red Beet Pigment Composition. Effects of Fermentation by Different Strains of Saccharomyces cerevisiae

Pasteurized red beet juice was inoculated with seven strains of Saccharomyces cerevisiae after adjusting pH to 5.8. Fermentation was at 26°C. The decay of red beet pigments was spectro-photometrically determined and expressed as betanine. Average percentages of betanine, isobetanine, betanidine, isobetanidine and the saccharide components were monitored by HPLC. After 40 hr fermentation, the strains Oenoferm, IO90 and Tokaj 76D showed pigment retentions and sucrose concentrations (g.L^-1) of 62% and traces, 58% and 3.4, and 56% and 1.4 respectively, and were considered the most suitable.     

Enhancement of surface acidity and catalytic activity by glass formation of calcium metaphosphate

Effective acid sites for the dehydration of 2-propanol and isomerization of 1-butene were found to be generated by glass formation of calcium metaphosphate. The number of these sites with strong acidity remarkably decreased by the crystallization of the glass, where the condensation of hydroxyl groups were significant. Thus, the sites must be the monohydrogen phosphate protons.     

载体酸碱性对钒基催化剂丙烷氧化脱氢性能的影响及其IR和EPR研究

应用ＩＲ和低温ＥＰＲ等方法研究了载体酸碱性对钒基催化剂丙烷氧化脱氢性能的影响。从ＶＳｎＯ、ＶＳｉＯ、ＶＴｉＯ、ＶＡｌＯ到ＶＭｇＯ，随着载体的碱性增强，丙烷转化率和丙烯选择性均提高，然而从ＶＭｇＯ、ＶＣａＯ、ＶＳ－ｒＯ到ＶＢａＯ，随着载体碱性的进一步增强，丙烯选择性仍提高，但丙烷转化率显著降低。这些结果表明，只有适度增强催化剂的碱性，才有利于生成Ｖ４＋离子，减少表面碳酸盐的生成，并缩短脱氢中间体在催化剂上的停留时间和促进丙烯的脱附，减少Ｃ－Ｃ键断裂和转化为ＣＯｘ的机会，从而有利于丙烷氧化脱氢生成丙烯。     

正己烷在几种改性分子筛上的氢转移反应

以正己烷为模型化合物，在接近工业催化裂化(FCC)过程的反应温度下，考察了几种改性分子筛在催化裂化过程中的氢转移反应性能。结果表明，分子筛中引入适量的磷、硼以及经过酸改性，可以有效地提高选择性氢转移反应而抑制非选择性氢转移反应。     

Effect of harvesting time and fruit size on titratable acidity, soluble solid and distribution of limonin in Thai tangerine juice

The effect of fruit size and harvesting of Thai tangerine fruit ( Citrus reticulata , Blanco) at different growth stages, 8–12 months after fruit set, on the distribution of limonin in whole fruit as well as in the individual fruit parts and extracted juice was investigated. The highest limonin concentration was observed in seed, followed by albedo, flavedo, segment membrane and juice sacs in decreasing order. The limonin concentration in juice as well as in whole fruit was decreased when fruit was harvested 8–12 months of fruit set. Increasing harvesting time from 8 to 12 months showed corresponding decreases in the amount of limonin in flavedo, albedo and seed. There was a decrease in titrable acidity and increase in total soluble solid and total soluble solid/titrable acidity ratio of juice with a later than normal harvesting time. However, fruit size showed no effect on limonin content and other properties of juice extracted from tangerine.     

TiO_2载体表面酸性的研究

利用NH_3吸附和吡啶吸附红外技术研究TiO_2的制备条件对其表面酸性的影响。结果表明,用NH_3水中和TiCl_4溶液方法制备的TiO_2(A)表面有较强的L酸中心,中和条件对表面酸性中心数目和强度有显著影响。由TiOSO_4水解方法制备的TiO_2(B)表面具有较强的L酸中心和较弱的B酸中心,引入不同添加剂可有效地调变TiO_2载体表面的酸性。     

Sulfated zirconia catalysts: Are Brønsted acid sites the source of the activity?

The thermal decomposition products of pyridinium sulfate differ from those of pyridinium sulfate supported on zirconia which in turn differs from that of pyridine adsorbed on a sulfated zirconia. Unsupported pyridinium sulfate decomposes to produce pyridine and sulfuric acid, and these subsequently react to produce oxides of carbon and sulfur. Zirconia that is sulfated and then exposed to pyridine does not release detectable amount of pyridine during heating in an inert gas; rather the pyridine undergoes oxidation reduction reactions simultaneously to release CO₂ and sulfur compounds. Pyridinium sulfate supported on zirconia decomposes upon heating to release pyridine and sulfuric acid, which reacts with the zirconia. The desorption of pyridine in one case and only CO₂/SO_x in the other case suggests that sulfated zirconia does not contain Brønsted acidity that can form pyridinium sulfate.