乙酸异丙酯催化合成研究进展

对乙酸异丙酯合成的催化剂研究进展进行了报道,综述了液态酸催化剂、固体酸催化剂、离子交换树脂催化剂、杂多酸（盐）催化剂。对以乙酸与丙烯或异丙醇为原料合成乙酸异丙脂的合成方法,特别是对乙酸的转化率、乙酸异丙脂的选择性作了详细的介绍。     

A reaming test for cutting fluid evaluation

As an alternative to tapping torque measurement and thread finish evaluation, a reaming test is suggested for the evaluation of the lubricating efficiency of cutting fluids. An investigation was carried out where results from tapping torque measurements were compared with those from measuring torque, feed force, and surface roughness in reaming. Two different tap geometries and two different reamer geometries were used. Technically-pure aluminium was used as the workpiece material and four laboratory water-based cutting fluids as well as a commercial cutting oil were investigated. The results show that lubricants have a significant and similar effect with respect to both tapping torque and reaming torque, when tools with straight flutes are used. In reaming, a more comprehensive picture of lubrication can be obtained if torque measurement is accompanied by determination of the surface roughness. In a subsequent investigation, the reaming torque and roughness test was used to evaluate two different water-based cutting fluids and a neat oil, using austenitic stainless steel as the workpiece material.     

无糖高纤维山楂醋饮料的研制

本文主要研究了以发酵型山楂原醋、麦芽糖醇、复合膳食纤维等原材料进行调配生产无糖高纤维山楂醋饮料的最佳配方及工艺,并对成品进行风味和稳定性检测实验.膳食纤维的最佳添加方式为:制成凝胶体后切成凝胶粒,再加入到饮料中.最佳配方为:山楂原醋15%,麦芽糖醇10%、柠檬酸0.2%、安赛蜜0.035%,大豆纤维素5.8%、魔芋葡甘聚糖0.4%、果胶0.3%、黄原胶0.1%、刺槐豆胶0.05%、阿拉伯胶0.05%.     

Ni-P/Si3N4复合镀层在醋酸溶液中腐蚀行为的研究

通过阳极极化曲线、交流阻抗谱和腐蚀失重实验研究了化学镀N i-P/S i3N4复合镀层在20%醋酸溶液中的腐蚀行为,并用SEM观察腐蚀前后镀层的形貌。实验结果表明:镀态N i-P/S i3N4复合镀层的耐蚀性能略高于N i-P合金;镀层中P质量分数升高,镀层的耐蚀性能增强;400℃热处理后复合镀层耐蚀性能明显降低。交流阻抗谱显示,N i-P/S i3N4镀层在醋酸溶液中的电极过程是受电荷转移和扩散步骤混合控制的。     

Water‐Tolerant and Reusable Catalysts for Direct Ester Condensation between Equimolar Amounts of Carboxylic Acids and Alcohols

ZrOCl₂⋅8 H₂O and HfOCl₂⋅8 H₂O are highly effective, water‐tolerant, and reusable homogeneous catalysts for direct ester condensation between equimolar amounts of carboxylic acids and alcohols. Notably, zirconium(IV) salts such as ZrOCl₂⋅8 H₂O and Zr(OAc)_x(OH)_y are potential green catalysts due to their low toxicity, commercial availability at low cost, ease of handling, high catalytic activity, and reusability.     

Thermal analysis of alternative diesel fuels from vegetable oils

The relatively poor cold-flow properties of monoalkyl esters of vegetable oils and animal fats (biodiesel) present a major obstacle to their development as alternative fuels and extenders for combustion in direct injection compressionignition (diesel) engines. In this work, differential scanning calorimetry (DSC) heating and cooling curves of methyl soyate (SME), methyl tallowate (TME), SME/TME admixtures, and winterized SME were analyzed. Completion of melt, crystallization onset (Onset), and other temperatures corresponding to melting and freezing peaks were correlated to predict cloud point (CP), pour point (PP), cold filter plugging point (CFPP), and low-temperature flow test (LTFT) data. Effects of treating methyl esters with cold-flow improvers were examined. Low-temperature flow properties of biodiesel may be accurately inferred from subambient DSC analyses of high-melting or freezing (β-form) peaks. The temperature of maximal heat flow for freezing peaks gave the best accuracy for predicting CP, PP, and CFPP, while freezing point gave the best accuracy for predicting LTFT. Onset also gave good correlations with respect to predicting PP, CFPP, and LTFT. Cooling scan parameters were more reliable than heating scan parameters. Presented at the 88th American Oil Chemists’ Society’s Annual Meeting & Expo, Seattle, Washington, May 11–14, 1997.     

Properties of rapeseed oil for use as a diesel fuel extender

Chemical and thermal analyses were carried out on degummed and filtered (5 μm) rapeseed oil (referred to as SRO, i.e., semirefined rapeseed oil) to determine its suitability as a diesel fuel extender. The upper rate for inclusion of SRO with diesel fuel is 25%. This fuel blend had a phosphorus level of 2.5 ppm, which was comparable to rape methyl esters (1.0 ppm phosphorus). Thermogravimetric analyses were used to estimate the cetane ratings of the fuels. A 25% SRO/diesel blend had an estimated cetane index of 32.4 compared to 38.1 for diesel fuel only. Differential scanning calorimetry and thermogravimetric analyses were used to compare the volatility ranges of the fuels. SRO needed higher temperatures for volatilization (i.e., 70–260°C for diesel fuel vs. 280–520°C for SRO). This indicated poorer cold-starting performance of SRO compared with diesel fuel. SRO fuel is a low-sulfur, high-oxygen fuel giving SRO a more favorable emissions profile than pure diesel fuel.     

一水合硫酸氢钠的催化酯化作用

研究了以一水合硫酸氢钠催化合成乙酸正丁酯的最佳反应条件,在相同反应条件下,利用一水合硫酸氢钠催化合成了乙酸和丙酸的８种酯,其收率在８５．９％～９６．２％之间。     

食品乳化剂柠檬酸甘油单,二酸酯的合成

采用以乙酸为溶剂,柠檬酸和单甘酯进行酯化反应合成了质量指标均符合ＦＡＯ／ＷＨＯ标准的柠檬酸甘油单,二酸酯,确定了合成的最佳工艺条件,并以此为原料配制了两种在常温下呈液态的复合型搞氧剂。试验结果表明,其抗氧化效果超过了国外同类产品,在油脂及含油食品中具有广泛应用价值。     

脱臭工艺和脱臭条件对菜籽油综合品质的影响

对菜籽油进行不同温度(210℃、230℃、250℃、270℃)、不同时间(60 min、80 min、100 min、100 min)的常规脱臭及双温脱臭(190℃/50 min+230℃、240℃、250℃、260℃、270℃/30 min),检测脱臭前后菜籽油中多环芳烃(PAHs)、3-氯丙醇酯(3-MCPD酯)、缩水甘油酯(GEs)、维生素E、植物甾醇、反式脂肪酸含量,分析研究不同脱臭工艺和脱臭条件对菜籽油综合品质的影响。结果表明：在常规脱臭工艺中,随脱臭温度升高和脱臭时间延长,PAHs脱除率提高,苯并芘(BaP)脱除率10.04%~45.08%;在适度脱臭条件下(230℃、60~120min),3-MCPD酯含量升幅均在0.3 mg/kg之内(从0.5升高至0.73 mg/kg),GEs含量升幅均在0.9 mg/kg之内(从1.19升高至2.04 mg/kg);230℃/60 min维生素E损失率为13.09%,230℃/120 min甾醇损失率15.86%,反式脂肪酸含量升高0.51%。采用190℃/50 min+260℃/30 min的双温脱臭工艺,BaP脱除率为36%;190℃/50 min+230℃/30 min双温脱臭后,3-MCPD酯和GEs含量为0.74、0.87 mg/kg,维生素E和甾醇损失率分别为7.20%、3.47%,未有反式酸生成。与单温脱臭工艺相比,双温脱臭对提升菜籽油综合品质有明显优势。