香料2,3-丁二酮的合成现状及展望

介绍了香料2,3-丁二酮合成的国内外研究现状,其中着重介绍了微生物发酵法生产中的菌种、工艺以及目标产物的检测方法及高产策略,并对利用微生物发酵法生产2,3-丁二酮存在的问题提出了一些解决方法,以期待减少环境压力,提高香料安全.     

气相色谱法分析2,3-丁二酮

建立了一种利用气相色谱测定丁二酮的定量分析方法。采用FID检测器和HP-5毛细管色谱柱,对2,3-丁二酮进行定量分析。以该方法测定2,3-丁二酮的平均回收率为101.5%,标准偏差（峰面积响应值）为18.5818,变异系数为0.59%,线性决定系数（r2）为0.9999。结果表明该方法适用于2,3-丁二酮的定量分析。     

2,3-丁二醇的发酵生产

能源危机和环境污染使得化工行业的发展举步维艰,亟待开发新的发展模式,以可再生能源为原料的生物炼制技术成为可行的途径之一。2,3-丁二醇的发酵生产是现代生物炼制的重要课题之一。2,3-丁二醇作为一种大宗的化学产品具有广泛的应用价值,尤其在化工、食品、燃料、医药等领域。本文简要描述了2,3-丁二醇在微生物体内的代谢途径,着重讨论了2,3-丁二醇的发酵生产,对发酵的菌种种类、菌种诱变和定向改造、各种发酵影响因素（包括底物、pH值、溶氧、温度以及发酵方式）进行了详细的归纳总结,同时展望了2,3-丁二醇发酵生产的研究发展方向。     

香料2,3-丁二酮在电子烟中的应用、管控及分析进展

近年来,随着电子烟的迅猛发展,由其导致的系列疾病也引起人们的重视,各国已开始关注电子烟中的化学组分可能带来的健康危害。2,3-丁二酮作为一种食品用香料被用在了电子烟液中,但研究发现它的使用会引起呼吸道疾病。本文总结了近年来国内外对2,3-丁二酮规定的相关标准和管控情况,同时也总结了色谱法检测2,3-丁二酮的最新进展。     

2,3-二甲基吡嗪的合成与应用概述

本文论述了以丁二酮与乙二胺和丁二醇与乙二胺等不同物质为原料的多种合成2,3-二甲基吡嗪方法,并对其在医药、农药、香料和分析化学等方面的应用做了概述。本文认为,2,3-二甲基吡嗪的合成发展趋势应采用气固相催化反应的方法,建议以价廉的丁二酮取代以往气相法中以2,3-丁二醇为原料的路线。     

在线红外光谱对2,3-丁二酮单肟钠盐的合成反应过程研究

利用在线红外光谱对2,3-丁二酮单肟钠盐的合成反应进行了在线监测,通过监测反应物2-丁酮（1719cm?1）、中间体2,3-丁二酮单肟（1693cm?1和3249cm?1）和乙醇（1026cm?1）以及最终产物2,3-丁二酮单肟钠盐（1643cm?1）特征峰的变化,推断了反应体系中各组分浓度的变化规律,从而比较清楚地了解了该反应的进程。结果表明,在线红外光谱能够快速、简便、准确地确定出反应结束时间,从而达到对合成反应过程进行控制的目的。     

生物基化学品2,3-丁二醇的研究进展

从2,3-丁二醇的发酵研究(菌株、非粮碳源、发酵工艺)和下游处理技术两方面对生物法生产2,3-丁二醇的研究进展进行了概述,并对不同的分离方法进行了比较,指出降低2,3-丁二醇的生产成本应从菌种选育、发酵工艺优化及高效廉价节能的分离工艺研究出发,并在此基础上进行系统优化、展开2,3-丁二醇的应用研究是今后生物法生产2,3-丁二醇研究应关注的问题.     

微生物发酵法生产2,3-丁二醇的研究进展

从发酵菌株、发酵底物、发酵工艺以及分离提取方法等方面概述了微生物发酵法生产2,3-丁二醇的研究进展,并讨论了2,3-丁二醇发酵过程中存在的问题,同时指出,选育理想菌株并进一步对2,3-丁二醇的生化代谢途径中不同酶的动力学行为展开针对性的研究、应用数学工具优化发酵工艺并在此基础上对2,3-丁二醇的系列衍生物进行开发应用是今后研究的重点。     

2,3,5,6-四甲基吡嗪合成新技术研究

采用2,3-丁二酮为生产原料,在过量液氨及过渡金属催化剂的存在下,将羰基还原为氨基,进而分子间缩合生成四甲基哌嗪,在催化剂络合Ni固载的催化下,逐步升温至脱氢温度,最终得到四甲基吡嗪产品。该项目生产成本低廉,反应步骤简单易操作,突破了副反应多,产品收率低的技术瓶颈。     

两株Klebsiella pneumoniae菌发酵生产2,3-丁二醇的比较

对两株克雷伯氏菌(Klebsiella pneumoniae)批式流加发酵生产2,3-丁二醇进行了研究,结果表明,K. pneumoniae CICC 10011代谢产生的各种有机酸和乙醇浓度均明显低于K. pneumoniae DSM 2026,发酵56 h,目标产物(2,3-丁二醇+乙偶姻)浓度为85.61 g/L,生产强度为1.53 g/(L×h),葡萄糖质量转化率为45%. 对2株克雷伯氏菌发酵的代谢流量分析表明,K. pneumoniae CICC 10011是生产2,3-丁二醇的优良菌株.     

Some carbonyl flavor compounds of oxidized soybean and linseed oils

Evidence is presented that 2,3-pentanedione, as well as diacetyl, contributes to the buttery flavor found in the early stages of oxidation of soybean oil. Components with a fishy and potatoey flavor were found in distillates from soybean oil that had a fishy or paint-like flavor. Linseed oil proved a reliable source of these flavor compounds. The fishy compound was identified ascis-4-heptenal and the potatoey compound is probably 2,4-pentadienal. Mechanisms for the production of these compounds are suggested. Journal Paper No. J-6183 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 1517.     

微生物合成2,3-丁二醇的代谢工程

2,3-丁二醇（2,3-BD）是一种重要的微生物代谢产物,广泛应用于食品、医药、化工等多个领域。微生物合成2,3-BD的效率不高一直制约着其生物制造工业化进程,应用代谢工程的理论和方法优化微生物的代谢途径有望解决这一问题。本文全面总结了近年来微生物合成2,3-BD研究过程中的菌株改造和构建技术,包括过表达合成途径中的关键酶编码基因、敲除旁路代谢途径关键酶编码基因、应用辅因子工程手段对天然菌株代谢网络进行重新设计和合理改造,以及利用合成生物学技术在模式菌株中构建全新的代谢途径,实现2,3-BD的高效生物合成。最后,本文对未来的研究方向进行了展望,提出了进一步利用先进的合成生物学方法构建高效细胞工厂的指导性建议。     

中国白酒风味化学物质指纹图谱库构想及实践

采用分析色谱技术,定量分析了飞天茅台、五粮液、枝江、白云边、山西汾酒、牛栏山二锅头及桂林三花酒等5大类7种不同香型的中国白酒。将其微量化学物质按国家卫生标准、体现白酒普通香味的微量化学物质以及具有特征香味的微量化学物质分为三大类,并按其含量和一定顺序用柱状图进行表达,从而得到其微量风味化学物质指纹图谱。尝试建立一种利用白酒微量化学物质指纹图谱鉴别白酒品质和香型的简易方法。     

Diacetyl as the buttery flavor component in soybean oil

Soybean oil often exhibits a buttery flavor in the early stages of autoxidation. Molecular distiliates from “buttery” soybean oil consisted of aqueous and oily layers. The aqueous layer contained the buttery flavor. During gas chromatography, the buttery flavor compound had a retention time similar to diacetyl on both polar and nonpolar columns. Diacetyl-bis-2,4-dinitrophenyl-hydrazone was isolated from the aqueous layer of the distillate. Diacetyl added to fresh soybean oil faithfully reproduced the buttery flavor. Journal Paper No. J-5107 of the Iowa Agricultural and Home Economics Experiment Station, Ames, Iowa Project No. 1517. Presented at the AOCS Meeting, Houston, April 1965.     

2,3,5-三甲基吡嗪的合成新工艺

以1,2-丙二胺与丁二酮为原料,用一步法合成2,3,5-三甲基吡嗪。最佳反应条件是:缩合起始温度为0℃,脱氢时间为9h,催化氧化剂的用量(摩尔比)为:丁二酮:碱=1:1,丁二酮:HL-2=1:3,在该最佳反应条件下产率达85％,精制后纯度达99％,沸点90～92℃/6.67kPa。     

Structure and properties of polyimide‐bonded magnets processed from prepolymers based on diacetyl derivatives of aromatic diamines and dianhydrides

We report a novel method of polyimide (PI) synthesis from prepolymers based on dianhydrides and diacetyl derivatives of aromatic diamines that facilitate the preparation of a melt processable mixture at 300 ± 10°C of the prepolymer and magnetic Nd‐Fe‐B alloy to provide PI‐bonded magnets with enhanced properties. It is shown that chemical structure of the prepolymers strongly influences viscosity behavior via crystallization of the oligoimide in the melt, leading to formation of PI with rigid‐rod like structure. This structural ordering of the prepolymers based on diacetyl derivative of diamine used in this study, if not controlled, leads to exponential increase of melt viscosity with time, making it practically impossible to prepare melt processable mixture of the magnetic particles and the PI prepolymers at elevated temperatures. The results obtained demonstrate that appropriate dianhydrides and diacetyl derivatives of diamines that do not lead to crystallization of oligoimides in prepolymer mixture can be used under controlled processing conditions to prepare melt‐processable PI‐bonded magnets containing rigid‐rod like PI structure that significantly increases thermal stability of the magnets. The temperature dependencies of the magnetic properties of the PI‐bonded magnets under conditions that they are likely to encounter during their service life were found to be remarkably similar to that of commercial thermoplastic magnets such as injection‐molded nylon magnets. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 478–485, 2006     

二乙酰己二胺与异氰酸酯合成聚脲反应动力学

采用酰基化方法对扩链剂1,6-己二胺进行了改性,并用凯氏定氮法,傅立叶红外光谱(FT-IR)和核磁共振氢谱(1H-NMR)分析了改性产物,确定产物为二乙酰己二胺.以二乙酰己二胺为扩链剂,与半预聚物4,4'-二苯甲烷二异氰酸酯(MDI)反应合成新型聚脲,考察了扩链剂1,6-己二胺改性对聚脲凝胶时间的影响,并采用FT-IR研究聚脲合成的反应动力学.结果表明,采用二乙酰己二胺为扩链剂,反应活性降低,凝胶时问延长,有利于动力学反应研究.在常温下,二乙酰己二胺与MDI合成聚脲的反应为二级反应,表观活化能为43.414 kJ/mol.     

Correlation of the flavor scores of vegetable oils with volatile profile data

One of the most important quality parameters to users of commercial vegetable oils is the flavor. For years, taste panels have been used to rate the overall quality of oils in terms of flavor scores. However, flavor scores are subjective, vary considerably among individuals and laboratories, and are not really diagnostic. The need for more adequate quality evaluation of oils has focused attention on chemical changes and sensitive instrumental methods which can be used to differentiate the stage of freshness or deterioration. Dupuy’s direct gas Chromatographic method for the examination of the volatile profile of vegetable oils has been applied to 23 fresh soybean oils, and the same 23 oils aged 5 wk in the light at 22 C. High correlation between the volatile profile data and the flavor scores was found. The most significant peaks which were positively correlated with flavor score and those which were negatively correlated were obtained, and a prediction equation of flavor score was calculated from the volatile profile data. Presented at the AOCS Meeting, New Orleans, April 1976.