反应精馏法制备高纯度醋酸甲酯

在中试反应精馏塔中以浓硫酸为催化剂进行了醋酸与甲醇反应制备醋酸甲酯的试验。反应精馏塔的精馏段为填料,反应段为立体催化精馏塔板,采用连续操作,考察了回流比、甲醇进料位置、停留时间、催化剂用量对反应精馏的影响。试验结果表明,当回流比为1.2、甲醇进料位置为第11～15块塔板、停留时间为2.2～2.5h、催化剂与醋酸的质量比为1.07∶100时,塔顶醋酸甲酯的质量分数达到99.50%以上,醋酸的转化率达到99.85%以上。     

Photocatalytic degradation of methyl orange using heteropolytungstic acid-encapsulated TiSBA-15

Heteropolyphosphotungstic acid (H₃PW₁₂O₄₀) (HPA)-encapsulated titanium-supported SBA15 nanoporous materials (HPA-TiSBA-15) were synthesized as a new photocatalyst, and they were characterized by FT-IR and ³¹P NMR MAS spectroscopic methods. Their photocatalytic effects on degradation of methyl orange in water were investigated under natural conditions, and it was found that a 4-fold increase in the photodegradation rate is observed in the presence of HPA-TiSBA-15 as compared to the rate observed in the presence of titanium-supported SBA15 nanoporous materials (TiSBA-15) without HPA.     

三种新型流量计在醋酸装置中的应用

阐述了阿牛巴、超声波、电磁等3种流量计的性能特点、选用原则和安装要点。重点分析了低压甲醇羰基化生产醋酸装置中的各种介质的特点如强腐蚀性、两相流、低电导率等,根据不同介质的特点和工艺要求选用不同类型的流量计,并且总结了这些流量计替代原有孔板、涡街、涡轮流量计的实际使用情况以及经验教训。     

纤维素的辐射裂解及其化学性质

纤维素经高能射线辐照,能产生一系列的化学和物理性质的变化。本文报道在不同剂量的~(60)Coγ射线辐照下,稻草中的水溶性糖、易水解糖、难水解糖,以及氨基酸、蛋白质等物质的化学变化;用辐射与加泡涨剂相结合的方法处理稻草,可以降低剂量、提高效应。     

利用高酸值餐饮废油脂制备生物柴油

以高酸值餐饮废油脂为原料,在酯化反应后再经两步酯交换反应制备生物柴油。在酯化反应中添加吸水剂可降低油脂的酸值,经一次酯化反应即可将油脂的酸值降至2m g/g左右,满足酯交换反应的要求。考察了酯化反应中吸水剂的添加方式、种类及其用量对酯化反应的影响,以及酯交换催化剂的种类及用量对脂肪酸甲酯(FAME)收率和产物组成的影响。实验结果表明,以凹凸棒土为吸水剂(用量为餐饮废油脂中游离脂肪酸质量的3%),且在酯化反应30m in时加入,酯化效果较好;以质量比为1∶1的NaOH和KOH混合物为催化剂进行两步酯交换反应时,催化剂的最佳用量依次为1.00%和0.75%(质量分数,基于油脂的质量),FAME收率最高达到96.33%。     

Antioxidative ability of native and thermized sour whey in oxidation‐catalysed model systems†

Antioxidative properties of sour (cottage) were evaluated with (thermized) and without (native) heat treatment (80°C for 30 min). A model system comprising a Tween 20 stabilized peanut oil in phosphate buffer (pH 7.0) emulsion containing lipid oxidation catalysts, FeCl ₃, H₂O₂ and ascorbate was used. Native sour whey powder (SWP) was significantly better than thermized whey in terms of limiting the formation of thiobarbituric acid‐reactive substances and peroxide value. Antioxidative ability was best at pH 3.0 and decreased with increasing pH. SWP (20%, w/v) was significantly better than all commonly used antioxidants tested after 96 h of incubation at 40°C.     

Fatty acids from Macoma sp. of bivalve mollusc

Fatty acids of the total lipids of flesh and hepatopancreas of Macoma sp. have been determined. The level of 20:5w3 (ca 17%), a biologically important fatty acid, was found to be considerably high. Other major component fatty acids were 16:0, 16:1, 18:1 and 22:4w6. High levels of 22:5w6 (8%), 22:5w3 (8%) and 22:6w3 (ca 15%) were found in flesh lipid. Nonsaponifiables were also high (28–30%). Alkyl ether acyl glycerols were found in flesh (1.3%) and hepatopancreas (3.8%).     

Phytic Acid Degradation in Complementary Foods Using Phytase Naturally Occurring in Whole Grain Cereals

Complementary foods based on cereals and legumes often contain high amounts of phytic acid, a potent inhibitor of mineral and trace element absorption. The possibility to degrade phytic acid during the production of complementary foods by using whole grain cereals as the phytase source was investigated. Whole grain rye, wheat, or buckwheat (10%) were added to cereal‐legume‐based complementary food mixtures, and phytic acid was shown to be completely degraded in a relatively short time (1.5 to 3 h) when incubated at optimal conditions for cereal phytase. The potential usefulness of the method for industrial production was demonstrated with a complementary food based on wheat and soybean.     

磷铝杂原子固体酸催化剂催化合成乙酸异丙酯

以丙烯和乙酸为原料 ,自制的磷铝杂原子固体酸作催化剂催化合成了乙酸异丙酯 ,考察了反应温度、反应压力、反应空速 (LHSV)及催化剂用量对酯化反应的影响 ,同时考察了固体酸催化剂的重复使用性。确定了最佳合成条件 :反应压力 1 5MPa,反应温度 1 60℃ ,反应空速2 0h-1,催化剂用量 2 0g。在此条件下 ,酯化率可达 91 5 % ,乙酸异丙酯选择性达 99 0 % ,且催化剂的重复使用性良好。     

影响硼酸结晶形状的因素

从硼酸的结晶机理入手,探讨了影响硼酸结晶形状及大小的因素,在合理地控制操作条件的同时,加入合适的晶习改性剂,可以加大硼酸结晶体的粒状比例。