降低上面发酵小麦啤酒头痛感的酿造条件优化

啤酒上头的原因主要是较高的醇酯比和乙醛含量。为降低上面发酵小麦啤酒头痛感,对其发酵条件进行优化,并通过气相色谱（GC）检测啤酒中高级醇、酯类和乙醛等风味物质含量。结果表明,最优发酵条件为发酵温度18 ℃（醇酯比2.02、乙醛含量3.51 mg/L）、发酵压力0.12 MPa（醇酯比2.01、乙醛含量2.75 mg/L）和零代酵母（醇酯比2.20、乙醛含量2.76 mg/L）。在此条件下发酵的小麦啤酒醇酯比为2.0～2.5,乙醛含量＜4 mg/L,不易引起上头。     

Predicting cetane numbers of n-alcohols and methyl esters from their physical properties

Cetane numbers (C#) for the homologous series of straight-chain, saturated n-alcohols, C₅−C₁₂ and C₁₄, were determined according to ASTM D 613. Measured C# ranged from 18.2–80.8 and increased linearly with carbon number (CN). Regression analyses developed equations that related various physical properties or molecular characteristics of these alcohols to calculated C#. The degree of relationship between measured and calculated C# was expressed as R². The decreasing order of the precision with which these properties correlated with C# was: boiling point (bp)>melting point (mp)>CN>heat of combustion (HG)>refractive index (n²⁰ _D)>density (d). This ranking was based upon R² (0.99–0.96) and the Average % error (2.8–7.2%). C# were also determined for straight-chain homologs of saturated methyl esters with CN of 6, 10, 12, 14, 16 and 18. C# ranged from 18.0–75.6 and increased curvilinearly with CN. Equations were also developed that related physical properties of these esters to C#. The precision with which these properties correlated with C# was: bp>viscosity (V)>heat of vaporization (HV)>HG>CN>surface tension (ST)>mp>n²⁰ _D>d. R² ranged from 0.99 for bp to 0.98 for d. Equations for the alcohols were linear or quadratic, while equations for the esters were linear, quadratic or cubic based upon statistical considerations that included a Student’s t-test. With related physical properties and these equations, accurate predictions of C# can be made for saturated n-alcohols and methyl esters.     

无配体碘化亚铜催化碘代芳烃与氨基醇的胺化反应研究

在40%的nBu4N+OH-水溶液中,采用碘化亚铜催化碘代芳烃与醇胺类物质进行胺化反应,合成了一系列含氮芳烃,并且效果很理想。该方法无需任何配体,同时具有经济、高效、环保等特点。产物的结构经1 H NMR、13C NMR、MS和元素分析证实。     

直接醇类燃料电池工作原理及研究进展

综述了直接醇类燃料电池的工作原理及最新进展,简述了此类电池存在的主要问题及关键技术,对发展质子交换膜和电催化剂技术提出了建议。     

计算脂肪醇沸点的新方法

直接从脂肪醇的分子结构提取4个结构参数:烷基的极化效应指数PEI、碳原子数目Nc、羟基所连接碳原子上的氢原子个数α-H和羟基与支链相对位置差ΔN,与118种脂肪醇的沸点进行相关分析,得到相关模型方程。运用留一法确证模型方程具有较好的稳定性和预测能力。方程所选用的参数计算简单,物理意义明确,能够被广泛使用。     

CO加氢合成低碳混合醇催化剂研究进展

介绍了低碳混合醇的性质及主要用途,对可用于CO加氢合成低碳混合醇的改性甲醇合成催化剂、改性F-T合成催化剂及Mo系催化剂的最新研究进展进行了介绍,并分析了现有催化剂存在的问题及发展的方向。     

气相色谱法测定合成气制烯烃水相产物中低碳醇、醛、酮、酸化合物

采用气相色谱法建立了合成气制烯烃(SGTO)水相产物中低碳醇、醛、酮、酸的测定方法,对分离条件进行优化,使用标准试样测定了线性范围和工作曲线,考察了方法的精密度和准确度,并采用该方法对SGTO实际水相产物中低碳醇、醛、酮、酸进行了测定。实验结果表明,在一定质量浓度范围内,低碳醇、醛、酮、酸各组分均呈现良好的线性关系,相关系数大于0.99。标样的回收率在93.4%~109.8%之间,6次重复测定的相对标准偏差小于3.9%。SGTO实际水相产物中低碳(C1~6)醇、醛、酮、酸的分析结果表明,SGTO实际水相产物中低碳(C1~6)醇、醛、酮、酸的总含量(w)在1.5%~3.0%之间;其中,乙醇的含量最高,丙酮其次。     

Japan Flavour and Fragrance Materials Association’s (JFFMA) safety assessment of food-flavouring substances uniquely used in Japan that belong to the class of aliphatic primary alcohols,aldehydes, carboxylic acids,acetals and esters containing additional oxygenated functional groups

ABSTRACT

We performed a safety evaluation using the procedure devised by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) of the following four flavouring substances that belong to the class of ‘aliphatic primary alcohols, aldehydes, carboxylic acids, acetals, and esters containing additional oxygenated functional groups’ and are uniquely used in Japan: butyl butyrylacetate, ethyl 2-hydroxy-4-methylpentanoate, 3-hydroxyhexanoic acid and methyl hydroxyacetate. Although no genotoxicity study data were found in the published literature, none of the four substances had chemical structural alerts predicting genotoxicity. All four substances were categorised as class I by using Cramer’s classification. The estimated daily intake of each of the four substances was determined to be 0.007–2.9 μg/person/day by using the maximised survey-derived intake method and based on the annual production data in Japan in 2001, 2005 and 2010, and was determined to be 0.250–600.0 μg/person/day by using the single-portion exposure technique and based on average-use levels in standard portion sizes of flavoured foods. Both of these estimated daily intake ranges were below the threshold of toxicological concern for class I substances, which is 1800 μg/person/day. Although no information from in vitro and in vivo toxicity studies for the four substances was available, these substances were judged to raise no safety concerns at the current levels of intake.     

国内外脂肪醇展望

本文介绍了脂肪醇，尤其是高碳醇的生产发展过程、国内生产能力、生产方法概述及主要生产方法和其开发应用情况，并呼吁要大力发展油脂和其衍生物脂肪醇相关工业，利用好脂肪醇促进国民经济腾飞．