乳酸氧气氧化法制备丙酮酸

丙酮酸是一种重要的有机合成和药物合成中间体 ,研究了以乳酸为原料 ,氧气催化氧化合成丙酮酸 ,并探讨了催化剂组成、用量、氧气用量、温度、反应时间等因素对合成反应的影响 ,确定了最佳合成条件 ,其条件为以 Pt/Pb( NO3) 2 /C为催化剂 ,其组成比为 3%∶ 5 %∶ 92 %(质量比 ) ,Pt用量为 0 .1 5 g(铂与乳酸的摩尔比为 1 .92× 1 0 -3) ,O2 加入量为 2 .33L/h(空气为 1 1 .1 L/h) ,在 45°C下反应 2 h时 ,收率为 66.0 %     

丙酮酸镁合成工艺的研究

研究了丙酮酸与碳酸镁反应合成丙酮酸镁的工艺过程.通过考察不同的原料配比、反应温度、反应时间以及终点控制,确定了最佳的合成条件:n(丙酮酸):n(碳酸镁)=2.1:1,在温度为65℃下反应60min,反应终点pH在4左右;在此条件下,丙酮酸镁的收率可达94.4%.     

VPO/TiO2催化乳酸乙酯绿色合成丙酮酸乙酯

以V_2O_5和磷酸为原料,采用有机相法制备负载型钒磷氧(VPO)催化剂,并考察了其在乳酸乙酯氧化合成丙酮酸乙酯反应中的催化性能。结果表明,n(P)∶n(V)=1.4∶1.0,TiO_2为载体制备的VPO/TiO_2最好;合成丙酮酸乙酯的最适宜条件为:n(乙腈)∶n(H_2O_2)∶n(乳酸乙酯)=12∶2∶1,催化剂添加量为10%(以乳酸乙酯质量计),反应温度65℃,反应时间5 h;在该条件下,乳酸乙酯的转化率为85.24%,丙酮酸乙酯的收率可达80.96%。催化剂重复利用5次,丙酮酸乙酯收率仍稳定在70%以上。通过对催化剂进行XRD、FTIR、XPS和钒价态分析,提出了反应机理可能涉及以V4+和V5+动态变化为活性中心的氧化还原循环。     

丙酮酸甲酯的合成

本文介绍了以丙酮酸和无水甲醇为原料,加入合适的催化剂合成丙酮酸甲酯的过程。通过对反应物配比、带水剂、反应时间等影响因素进行对比试验,确定以四氯化碳为带水剂,最佳反应配比为:丙酮酸∶无水甲醇∶四氯化碳=1∶2.5∶0.28,产物收率可达73.9%。该工艺过程简单,易操作,适合工业化大生产。     

丙酮酸的发酵代谢机理研究

近年来,丙酮酸广泛用于医药、化工、保健品等行业中,应用领域不断扩大,世界上需求量不断增长。发酵法生产丙酮酸由于具有成本低廉、产品纯度高、反应条件温和、对环境友好而得到发展。论述了代谢分析在丙酮酸发酵中的应用,包括乙酸渗漏菌株的筛选、能量代谢调控等,同时指出了今后的研究方向。     

一种高效无污染合成丙酮酸乙酯的新方法

研究了由次氯酸钠和溴化钠催化氧化乳酸乙酯合成丙酮酸乙酯新工艺。并通过正交试验设计方法 ,得出最佳实验操作条件 :温度为 30℃以下 ,反应时间为 8h ,溴化钠与乳酸乙酯的摩尔比为 1∶2 ,盐酸与溴化钠的摩尔比为1∶1. 4,不采用光照 ,并由此得到丙酮酸乙酯最好收率为 82 . 86 %(文献值为 80 . 2 %) ,乳酸乙酯的转化率为10 0 %。     

超细硼酸锌的水热法合成及表征

硼酸锌是一种环境友好型无机阻燃剂。以二水乙酸锌和硼酸为原料,以三乙胺为模板剂,利用水热法合成超细硼酸锌。采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)和扫描电子显微镜(SEM)等分析测试手段对制备的产品进行表征,并研究各因素对水热合成反应的影响,确定适宜的反应条件:n硼酸∶n乙酸锌为4∶1、晶化时间为15h,晶化温度为180℃。合成的产品为棒状晶体、粒度在2～3μm左右,颗粒大小均匀,分散性较好,符合超细产品的要求。     

复分解反应合成二烷基二硫代磷酸锌

以丁铵(二正丁基二硫代磷酸铵)和氯化锌为原材料,采用复分解反应合成二正丁基二硫代磷酸锌(ZBPD)。在合成中用正交方法对合成条件与产品产率的关系进行研究,最终确立了优化的合成工艺反应温度为30-40℃、物料摩尔比为2∶1-2∶1.1的丁铵和氯化锌反应4 h,此时所得到的产物ZBPD产率约为75%,锌含量11.3%-12.9%。并且讨论了产品后处理过程中脱水步骤与产品含水量的关系。     

1,2-丙二醇合成丙酮酸及丙酮酸甲酯

在常压下,以1,2-丙二醇为原料,采用两步法合成丙酮酸及丙酮酸甲酯.首先在固定床上以负载银的分子筛为催化剂,空气中的氧为氧化剂,气相氧化1,2-丙二醇合成丙酮醛,丙酮醛与甲醇气相预混合,以NbFeAPSO-5双功能分子筛为催化剂进行氧化酯化反应合成丙酮酸及丙酮酸甲酯.考察了反应温度、氧气与1,2-丙二醇(或丙酮醛)的物质的量比和1,2-丙二醇(或丙酮醛)液空速对反应的影响.结果表明,第一步丙二醇氧化反应制丙酮醛较优的工艺条件为320℃,氧醇物质的量比为1.2,1,2-丙二醇液空速为1.0 mL/(g·h);第二步丙酮醛的氧化酯化反应较优的工艺条件为140℃,甲醇的液空速为1.1 mL/(g·h),氧醛物质的量比为2.2.在此条件下,1,2-丙二醇的转化率可到达67.27%,丙酮醛的选择性为78.61%,丙酮酸和丙酮酸甲酯总的收率可达53.52%.     

水性油墨助剂十二胺基氯乙酸钠的合成与性能研究

以十二胺和二氯乙酸为原料合成十二胺基氯乙酸钠(DSC)。粗产品十二胺基氯乙酸(DCA)的较佳合成工艺条件为:n(二氯乙酸)∶n(十二胺)=1∶1.5,催化剂用量为1%,于120℃下反应18 h,产率为58.91%。对目标产物DSC采用IR进行结构表征,由表面活性分析可知其cmc为3.38×10-3mol·L-1,γcmc为27.43 mN·m-1,通过吸光度及粒径分析得到对水溶性油墨色浆分散性较好时其用量为1.6%。     

色氨酸酶重组基因表达及其酶法合成L-色氨酸

为实现色氨酸酶高效、低成本催化合成L-色氨酸,利用p ET30a为载体在宿主细胞E.coli BL21(DE3)中重组表达了产气肠杆菌(Enterobacter aerogenes)来源的色氨酸酶,以丙酮酸、吲哚和氨为底物,探究其酶学性质,考察了反应温度、起始p H、底物摩尔比对酶促反应的影响,并利用丙酮酸发酵液为底物酶法合成L-色氨酸。结果表明,色氨酸酶重组表达成功,色氨酸酶最佳反应条件为:温度35℃,起始p H=9.0,底物摩尔比n(吲哚)∶n(丙酮酸)=0.6∶1,底物丙酮酸浓度为0.17 mol/L。利用重组色氨酸酶全细胞催化100 m L浓度为0.57 mol/L丙酮酸发酵液,流加浓度为4.27 mol/L吲哚酒精溶液6.5 m L,反应28 h后,L-色氨酸浓度达0.25 mol/L,吲哚摩尔转化率达91.8%。     

抗癌药物比卡鲁胺

介绍过期专利抗癌药物比卡鲁胺的基本性能和作用。并概述了分别以溴丙酮、2-甲基丙烯酰氯、2-甲基丙烯酸甲酯、2,3-二羟基-2-甲基丙酸以及丙酮酸或丙酮酸酯为起始原料合成比卡鲁胺的方法。其中以丙酮酸或丙酮酸酯为原料的合成方法为最佳。     

Chemistry of Pyruvate Enolates: anti‐Selective Direct Aldol Reactions of Pyruvate Ester with Sugar Aldehydes Promoted by a Dinuclear Zinc Catalyst

A chiral dinuclear zinc complex can effectively catalyse the direct aldol reactions of pyruvic acid ester with various chiral sugar aldehydes, thus functionally mimicking the pyruvate‐dependent type II aldolases. Application of sterically hindered aryl esters allows for the elusive aldol reaction of the pyruvate donor with controlled anti‐selectivity en route to the short and efficient synthesis of 3‐deoxy‐2‐ulosonic acids. Pyruvic acid ester is here used as a chemical equivalent of phosphoenol pyruvate (PEP) in imitation of the synthetic principle used in nature. The presented biomimetic methodologies use enol formation for the highly efficient and flexible formation of various C₆–C₉ ulosonic acids. Particularly, efficient and concise syntheses of 3‐deoxy‐D ‐erythro‐hex‐2‐ulosonic acid (KDG, overall 50% yield), 3‐deoxy‐D ‐ribo‐hept‐2‐ulosonic acid (DRH, overall 53% yield) and 3‐deoxy‐D ‐glycero‐D ‐talo‐non‐2‐ulosonic acid (4‐epi‐KDN, overall 78% yield) are described. This direct efficient application of pyruvic esters does not require additional demasking steps and thus surpassess previously methodologies utilising masked pyruvic synthons such 2‐acetylthiazole and pyruvic aldehyde dimethyl acetal.

     

Process development and modeling of pyruvate recovery from a model solution and fermentation broth

The mono- and bi-polar electrodialysis processes for pyruvate recovery and pyruvic acid generation, respectively, were examined in order to determine their feasibility for application in the pyruvate production process. Under optimum process conditions (constant current mode i = 39.7 A m⁻², pyruvate model solution c_p = 50 g dm⁻³ in the monopolar electrodialysis experiment pyruvate flux reached 367 g m⁻² h⁻¹ and specific energy consumption was 1.4 kWh kg⁻¹. In the bi-polar electrodialysis experiment under optimum process conditions (constant current mode i = 9.6 A m⁻², pyruvate model solution c_p = 48 g dm⁻³, pyruvate flux reached 125 g m⁻² h⁻¹ and specific energy consumption was 1.5 kWh kg^-1. Generally speaking, performances of the bi-polar electrodialysis were equal to the best process conditions observed with mono-polar electrodialysis. On the other hand, current densities investigated in the bi-polar electrodialysis experiments were four-fold lower than those applied in the mono-polar electrodialysis experiments. Additionally, a mathematical model to represent the ion and water transport behavior of an electrodialysis process for concentrating pyruvic acid under the influence of different current density was developed. Estimation of both the model parameters and model validation were demonstrated in the work.     

π-氧化樟脑的合成

以(+)-樟脑为原料,先经二次溴化、还原得(+)-π-溴代樟脑,再经酯化、水解和氧化反应合成了强心药物π-氧化樟脑。确定了较佳工艺条件:(1)溴化反应:n〔(+)-樟脑〕∶n(Br2)=1∶1.4,冰醋酸为溶剂,80℃下反应6h,(+)-α-溴代樟脑收率88.5%;n〔(+)-α-溴代樟脑〕∶n(Br2)=1∶1.1,氯磺酸为助剂,室温下反应2 h,(+)-α,π-二溴代樟脑收率80.1%。(2)还原反应:n〔(+)-α,π-二溴代樟脑〕∶n(Zn)=1∶3,冰醋酸为溶剂,冰浴反应3h,(+)-π-溴代樟脑收率66.3%。(3)酯化-水解反应:n〔(+)-π-溴代樟脑〕∶n(CH3COOK)=1∶1.5,冰醋酸为溶剂,190℃下反应30 h,除去溶剂后用V(CH3CH2OH)∶V〔w(KOH)=55%的水溶液〕=1∶9的水解液,回流反应2.5 h,(+)-π-羟基樟脑收率78.1%。(4)氧化反应:选用氯铬酸吡啶嗡盐(PCC)作氧化剂,n(PCC)∶n〔(+)-π-羟基樟脑〕=2∶1,CH2Cl2作溶剂,氮气保护下室温反应2 h,π-氧化樟脑收率95.5%。目标产物总收率35%。中间体及目标产物结构经IR、GC-MS和1HNMR确证。     

Fatty acid and sterol synthesis by rat small intestine in vitro

Slices of rat jejunum were incubated with [2-¹⁴C]pyruvate, [1-¹⁴C]acetate, or [³H]H₂O to determine lipogenic activity. Under all conditions studied, pyruvate acted as a better precursor than acetate for fatty acid synthesis but not for the synthesis of sterol. Exogenous glucose significantly (P≤0.05) increased the conversion of both pyruvate and acetate to fatty acids. By contrast, fasting resulted in a decrease (p≤0.05) in lipogenic activity. The highest levels of lipogenesis were observed when [³H]H₂O + glucose at a concentration of 20 mM was used. From such experiments, the absolute rate of fatty acid synthesis in the tissue preparation was calculated: 734±54 nmoles acetyl units incorporated into fatty acids/g tissue/hr.     

2-(4-苯氧基苯基)乳酸乙酯的合成研究

以二苯醚与丙酮酸乙酯为原料,经傅克酰基化一步合成恶唑菌酮关键中间体2-(4-苯氧基苯基)乳酸乙酯,考察了溶剂、投料比、AlCl3用量、缚酸剂、温度对收率的影响。-25℃,CH2Cl2为溶剂,NaHCO3为缚酸剂,n(二苯醚)∶n(丙酮酸乙酯)∶n(AlCl3)=1.4∶1.0∶1.2,2-(4-苯氧基苯基)乳酸乙酯收率86.2%,目标产物结构经IR、1 H NMR确证。     

Dendritic polymers from vinyl ether

1-[(2-Vinyloxy)ethoxy]ethyl acetate (1) was prepared by the addition reaction between ethylene glycol divinyl ether and acetic acid. 1 contains both a cationically polymerizable C=C double bond and a dormant initiating moiety for cationic polymerization. It can, therefore, undergo self condensing cationic polymerization in the presence of a Lewis acid activator, such as zinc chloride. Using this procedure, a novel dendritic polymer consisting of vinyl ether was prepared and its hyperbranched molecular structure confirmed by FT-IR and ¹H NMR spectra. Received: 22 May 1997/Revised: 17 July 1997/Accepted: 6 August 1997     

甘氨酸锌螯合物的合成与结构表征

以甘氨酸和碱式碳酸锌为原料合成了甘氨酸锌螯合物 ,最佳工艺条件为 :n (甘氨酸 )∶n(碱式碳酸锌 ) =1 0 0∶0 35 ,温度 95℃ ,反应时间 8h ,产率≥ 92 %。用元素分析、红外光谱、热重差热分析、X射线粉末衍射对螯合物进行了表征 ,其组成为 [Zn(NH2 CH2 COO) 2 ]·H2 O。X射线粉末衍射数据指标化结果表明所合成的螯合物属于单斜晶系 ,晶胞参数为 :a =0 76 42nm ,b =1 182 7nm ,c =1 6 46 5nm ,β=81 75° ,V =1 472 7nm3 。     

Effect of Exogenous Factors on Bacteriocin Production from Lactobacillus paracasei J23 by Using a Resting Cell System

A resting cell system was developed for bacteriocin Lac-B23 production from Lactobacillus paracasei J23. The resting cell medium contained (g/L): Glucose 20, Sodium acetate 5.0, MnSO₄ 0.25 MgSO₄ 0.5, Ammoniumhydrogencitrate 1.0, KH₂PO₄ 1.0. The resting cell incubation time and temperature were 20 h and 37 °C and the effects of exogenous factors, including amino acids, glycerol, pyruvic acid, and α-ketoglutaric acid were investigated. Cys and Gly could stimulate the production of bacteriocin, while no stimulus effect was observed for Glu, Tyr and Ala. Glycerol and pyruvic acid increased bacteriocin production and the optimum concentrations were 1% and 30 g/L, respectively. Bacteriocin could act as an inducer of its own biosynthesis. These findings are of importance for the further study of bacteriocin biosynthesis regulation and for the improvement of bacteriocin production yields.