油茶籽油中邻苯二甲酸酯类塑化剂的检测方法及迁移规律的研究

该文建立了凝胶渗透色谱净化―气相色谱质谱同时测定油茶籽油中15种邻苯二甲酸酯的方法,并研究了邻苯二甲酸酯类污染物迁移规律。结果表明:该方法在线性范围内具有良好的线性关系,相关系数均大于0.999,检测限在0.10~0.90 mg/kg之间,平均回收率在84.3%~109.2%范围内,相对标准偏差为1.86%~9.21%。另外,储存温度越高,储存时间越长,邻苯二甲酸酯类污染物的特定迁移量越大。     

双氧水稳定剂HDPS的合成和应用

叙述了膦酸酯低聚物的合成过程及在氧漂中的作用机理,并与不同稳定剂进行了稳定性效果比较。经应用试验表明:膦酸酯低聚物是一种理想的新型氧漂稳定剂,产品白度和其他指标超过目前采用的水玻璃,且无硅垢;强碱条件下用镁复盐作稳定剂,前处理三步法可缩为一步法,大大节约能源,提高经济效益.     

Enzymatic synthesis of monoacylglycerol citrate optimized by response surface methodology

The ability of immobilized lipase B from Candida antarctica (Novozym 435) to catalyze the direct esterification of citric acid (CA) and monoglyceride (MG) for citrate esters of monoacylglycerols (CITREM) preparation was investigated. The effects of substrate concentration, molecular‐sieve amount, substrate molar ratio, reaction temperature, time, and enzyme load on the conversion of CA in the reaction were investigated. Enzyme screening and the effect of solvent on the esterification were also investigated. RSM was used to optimize the effects of the reaction temperature (45–55°C), the enzyme load (6–10%; relative to the weight of total substrates), and the reaction time (24–48 h) on the conversion of CA. Validation of the RSM model was verified by the good agreement between the experimental and the predicted values of CA conversion. The optimum preparation conditions were as follows: CA concentration 0.12 mol/L, molecular‐sieve 120 g/L, molar ratio of MG/CA 2:1, temperature 54.18°C, enzyme load 9.0% (relative to the weight of total substrates), and reaction time 47.5 h. Under the suggested conditions, the conversion of CA was 77.4%. Repeated reaction tests indicated that Novozym 435 could be used eight times under the optimum conditions with 92% of its original catalytic activity still retained.     

A comparison of the indirect and direct quantification of glycidol ester by kinetic analysis

In a comparison of the German society's official indirect method and the direct LC‐MS method to determine the levels of glycidol fatty acid esters (GEs) in edible oils, the indirect method showed lower GE levels in cases of a high level of GEs and/or containing partial acylglycerols (PGs). The present study used kinetic analysis to compare the scope of both methods. A kinetic model combination of reversible decomposition of GEs and 3‐monochloro‐1,2‐propanediol forming substances (MCPD‐FS) generated from PGs accurately predicted a persistent level of underestimation of commercial vegetable oils when the indirect method was used. The results of the kinetic prediction showed that the underestimation in the indirect method was proportional to the PG and GE levels in oils. Although most conventional cooking oils are low in GEs and PGs, significant error may occur in oils such as palm oil, which are reported to have a higher content of GEs and DAGs. The direct method was affected by neither the GEs nor the PGs, and proved to be a truer and more accurate determinant of GE levels in a wide range of edible oil products.     

亚磷酸三双酚A酯的合成研究

以三氯化磷和双酚A为原料合成了抗氧剂亚磷酸三双酚A酯.探索了反应溶剂、三氯化磷滴加时间、滴加温度及物料配比等反应条件对产率的影响.结果表明:反应溶剂为乙醚,三氯化磷滴加时间为20 min,滴加温度为25℃,物料配比[n(双酚A)∶n(三氯化磷)]为3.00∶1.05.在最适宜工艺条件下所制得的产品为白色固体,熔点为64...     

羧酸酯加氢金属催化剂研究进展

羧酸酯通过催化加氢可以制备高附加值的醇、醛和酸,该类反应得到了广泛地研究.回顾了羧酸酯催化加氢所使用的金属催化剂,重点讨论了铜基催化剂、锰氧化物催化剂、贵金属铑、钌、铂和钯催化剂在羧酸酯加氢反应中的应用,并对羧酸酯加氢反应中环境友好的新型催化剂进行了展望.     

Identification, FT-IR, NMR (H and C) and GC/MS studies of fatty acid methyl esters in biodiesel from rocket seed oil

Biodiesel was synthesized from rocket seed oil by base-catalyzed transesterification with methanol. The synthesis of biodiesel was confirmed by FT-IR and NMR (¹H and ¹³C) spectroscopy. Various fuel properties of the synthesized biodiesel were determined using ASTM methods and discussed accordingly. A total of eleven fatty acid methyl esters (FAMEs) were identified in rocket seed oil biodiesel (RSOB) by the retention time and the fragmentation pattern data of GC/MS analysis. The identified FAMEs were, methyl 9-hexadecenoate (C16:1), 14-methyl pentadecanoate (C16:0), methyl 9,12-octadecadienoate (C18:2), methyl 9-octadecenoate (C18:1), methyl octadecanoate (C18:0), methyl 11-eicosenoate (C20:1), methyl eicosanoate (C20:0), methyl 13-docosenoate (C22:1), methyl docosanoate (C22:0), methyl 15-tetracosenoate (24:1) and methyl tetracosanoate (C24:0). The percentage conversion of triglycerides to corresponding methyl esters determined by ¹H NMR was 88.49%.     

Alkali Metal tert‐Butoxides,Hydrides and Bis(trimethylsilyl)amides as Efficient Homogeneous Catalysts for Claisen–Tishchenko Reaction

Shelf‐available alkali metal tert‐butoxides, hydrides and bis(trimethylsilyl)amides were shown to be highly efficient homogeneous precatalysts for the disproportionation of aldehydes to the corresponding carboxylic esters. Potassium compounds in combination with 18‐crown‐6 ether could drastically increase the rate of reaction in a few cases. Alternatively, efficient aldol condensations were found for aldehydes possessing an enolizable methylene group at the α‐position to the aldehyde functionality. The active species involved in this esterification using any of these alkali metal catalysts is expected to be the metal alkoxide. Potassium compounds were found to be much more efficient when compared to analogous sodium compounds and kinetic studies revealed the rate‐determining step to be a second order concerted hydride transfer from a potassium hemiacetal species to another molecule of aldehyde.     

Esterification of Fatty Acids in Greases to Fatty Acid Methyl Esters with Highly Active Diphenylamine Salts

Diphenylamine sulfate (DPAS) and diphenylamine hydrochloride (DPACl) salts were found to be highly active catalysts for esterification and substantial transesterification of inexpensive greases to fatty acid methyl esters (FAME). In the presence of catalytic amounts of DPAS or DPACl and excess methanol, the free fatty acids as well as the acylglycerols in waste greases were converted to FAME at 125 °C within 1 h. Although the DPAS and DPACl catalysts were found to have similar catalytic activities to their parent liquid acids (i.e., sulfuric and hydrochloric acids) the diphenylammonium salts are much easier to work with than concentrated liquid acids.     

饮用水中邻苯二甲酸酯的调查及去除研究

采用固相萃取-高效液相色谱法调查了淮南市某自来水厂原水、各处理工艺单元出水中4种邻苯二甲酸酯(DMP、DEP、DBP、BBP)。结果表明,4种邻苯二甲酸酯在原水中均检出,质量浓度为0.010～0.142μg/L;DMP和DEP仅在部分水样中检出,在管网水中没有检出;DBP和BBP在各水样中均检出,质量浓度分别为1.702～2.897μg/L、0.248～0.676μg/L,说明现行常规净水处理工艺不能完全去除邻苯二甲酸酯,需要进行深度处理。研究采用臭氧氧化技术、活性炭吸附技术和臭氧-活性炭技术对该水厂原水中的2种邻苯二甲酸酯(DBP、BBP)去除情况进行验证。结果表明,臭氧氧化技术不能完全去除原水中的DBP和BBP,去除率为61%～65%;活性炭吸附技术能够完全去除原水中的DBP和BBP;臭氧-活性炭技术对原水中的DBP和BBP去除率达到100%。该技术可以作为水厂深度处理工艺去除DBP和BBP的主要单元。