癸二酸二缩水甘油酯的合成

以癸二酸为原料,合成了癸二酸二缩水甘油酯(DGSE),其结构经1H NMR,MS和元素分析表征。优化反应条件为:癸二酸100 mmol,n(癸二酸)∶n(NaOH)∶n(环氧氯丙烷)=1∶2∶3,催化剂x(四乙基溴化铵)=0.5%,回流反应2 h。在优化反应条件下,DGSE的收率93.4%,纯度82.6%。     

癸二酸二辛酯非酸性催化合成

以癸二酸与２－乙基己醇为原料，铝酸盐为催化剂，合成了癸二酸二辛酯。考察了影响合成收率的各种因素。在醇酸摩尔比为２．５∶１、催化剂用量为０．０４～０．０５％、反应温度２２０～２３０℃及反应时间２．５ｈ的最佳条件下，产品收率＞９８％。     

脂肪族聚酯弹性体的合成及其性能研究

介绍了一种以癸二酸、乙二醇和甘油为原料合成可降解脂肪族聚酯的方法,并利用红外光谱、光电子能谱、示差扫描量热法、X射线衍射和力学测试等方法对聚酯的性质进行了研究.结果显示,产物表现出典型的高弹性,随着原料中癸二酸/乙二醇的比值增加,产物的弹性模量呈增加趋势,微观结构由局部有序向无序转变.产物具有良好的生物降解能力,37℃下在含猪胰脂肪酶的磷酸缓冲溶液里72h失重率在6.1%～14.4%之间.     

癸二酸二水杨酰肼的合成

分别以水杨酰肼和癸二酰氯,或水杨酰氯和癸二酸二酰肼为原料合成了癸二酸二水杨酰肼(5),其结构经1H NMR, 13C NMR, MS和元素分析表征.合成5的较适宜反应条件为:癸二酰氯13 mmol, n(水杨酰肼) ∶ n(癸二酰氯)=2.2 ∶ 1.0,三乙胺作缚酸剂,DMF作溶剂,于90 ℃反应7 h,收率80%.     

铂与社会

铂是一种重要的贵金属,是化工、能源、石油炼制上的常用催化剂,是冶金工业制备高温电阻温度计的必须材料,是制造白金首饰的基本原料.铂的化合物——顺铂更是目前结构最简单的抗癌药物.本文概述了铂的性质、应用和工业制法,介绍了白金首饰的类型和检验方法,顺铂的抗癌机理.     

反,反-2,8-癸二烯二酸的合成

以癸二酸为原料,经α-溴代反应、Finkelstein反应和消除反应合成了反,反-2,8-癸二烯二酸。本合成方法可以与基础有机化学内容相结合,考虑作为一个基础有机化学实验的内容。     

一种新型高效醛化催化剂

中国科学院兰州化学物理研究所结合催化研究室采用低压羰基合成路线,已在近期研制出铂系新型络合物催化剂,并利用乙烯和己烯为原料,低压醛化反应制丙醛和庚醛、取得了可喜的结果。铂系催化剂采用高价铂和低价铂为原料,加入配     

四氯化锡催化合成癸二酸二丁酯

在五水四氯化锡作用下,用癸二酸和正丁醇合成了癸二酸二丁酯。当癸二酸、正丁醇和四氯化锡的物质的量之比为1∶8∶0.114,回流分水60 min,酯收率达96.2%。并比较了几种Lewis酸合成癸二酸二丁酯的催化活性。     

氯化铁催化合成癸二酸二丁酯的研究

癸二酸二丁酯是无色透明的液体,具有水果香味和淡的油脂气味,它可作主增塑剂和一些树脂和橡胶的溶剂,由于本品无毒,在食品工业上可用于食品接触的包装材料,也可用于配置水果香精.它通常是在硫酸作催化剂的条件下由癸二酸和正丁醇酯化反应而得[2] ,但硫酸腐蚀性很强,化学性质很活泼,反应中副反应较多,且后处理复杂,收率不高.因此国内外许多化学工作者都在探索用更佳的催化剂取代硫酸.俞善信等发现氯化铁(FeCl3·6H2O)是催化合成低级脂肪酸酯的良好催化剂[3,4],它具有原料易得,酯化活性高,操作方便,后处理简单,腐蚀性低等优点.本文采用氯化铁作催化剂合成癸二酸二丁酯,讨论了影响反应的因素,在适当的条件下酸的转化率可达96.73%.     

纳米复合固体超强酸SO42-/ZnFe2O4的制备与催化合成癸二酸二乙酯的研究

以硫酸盐为原料,添加NaOH和NaHCO₃以制备出碱式碳酸盐前驱体,合成出新型的纳米固体超强酸催化剂SO₄^2-/ZnFe₂O₄,经XRD、BET、IR等检测,粒径为35nm,比表面积很大(137m^2-1),粒度均匀。首次以该固体酸为催化剂,癸二酸和无水乙醇为原料合成癸二酸二乙酯,考察了影响反应的因素。结果表明,醇酸摩尔比为4.0∶1,催化剂用量为1.0g(癸二酸0.1mol),带水剂苯15mL,反应时间2.5h是最佳反应条件,酯化率可达91%,并推断出该催化剂的酸强度-16.02< H_o< -14.52.     

Dimethyl carbonate (DMC) electrolytes – the effect of solvent purity on Li–ion intercalation into graphite anodes

Graphite electrodes cycled in single solvent electrolytes based on dimethyl carbonate (DMC) exhibit surprising and unfamiliar behavior. The electrochemical performance of graphite anodes cycled vs. Li metal in DMC electrolytes, containing 1 M LiPF₆ is strongly dependent on the solvent purity. The behavior of the graphite anodes in electrolytes containing “pure” DMC is dependent mainly on the identity of the contamination present in the native solvent. It was found that methanol is causing deterioration in the electrochemical performance of the cycled graphite electrode, while carbon dioxide and mainly carbonochloridic acid methyl ester are enhancing the performance. It was established that it is essential to investigate and understand the processes and materials used during the production of battery grade solvents, in order to clarify the roll of traces of chemical compounds responsible for the variation and modification in the electrochemical behavior of the cycled electrodes.     

Occupational exposure to low levels of organic and inorganic substances in a chemical plant for the production of terephtalic acid dimethyl ester

The aim of our study was the evaluation of personal exposure to chemical pollutants in workers employed in a plant for the production of terephtalic acid dimethyl ester. Chemical agents have been included in the monitoring program on the basis of the industrial process. In the plant, the oxidation of p-xylene is performed by air and the resulting acid is esterified with methyl alcohol. Purified terephtalic acid dimethyl ester is then utilized for the production of polyethylene terephtalate. The environmental monitoring included terephtalic acid dimethyl ester, p-toluic acid methyl ester, terephtalic acid, p-xylene, methylacetate, methylbenzoate, formic acid, acetic acid, methanol, and the catalysts cobalt acetate and manganese (II) acetate tetrahydrate. Personal exposure to the cited airborne substances was performed in the breathing zone of six workers. Air samplings were carried out by drawing air through glass fibre filters (terephtalic acid dimethyl ester, p-toluic acid methyl ester and terephtalic acid aerosols), by active adsorption (methanol, formic and acetic acids vapours). p-Xylene, methylacetate and methylbenzoate vapours were collected by passive sampling. Cellulose nitrate filters were used for cobalt and manganese salts samplings. Analyses were performed by UV detection high-performance liquid chromatography (terephtalic acid dimethyl ester, p-toluic acid methyl ester and terephtalic acid), flame ionization detection gas chromatography (p-xylene, acetic acid methyl ester and benzoic acid methyl ester), ion chromatography (formic and acetic acids) and inductively coupled plasma-mass spectrometry (cobalt and manganese). The results were evaluated according to the threshold limit values (TLVs) of the American Conference of Governmental Industrial Hygienists (ACGIH) and indicated that the environmental levels of the workplace pollutants were well below the threshold limit values-time weighed average (TLV-TWA) adopted by the American Conference of Governmental Industrial Hygienists for 2002, although for three substances the TLVs were not available.     

Reactions of arylaldehydes and N-sulfonated imines with dimethyl acetylenedicarboxylate catalyzed by nitrogen and phosphine lewis bases

[reaction: see text] In the reaction of arylaldehydes or N-sulfonated imines (0.5 mmol) with dimethyl acetylenedicarboxylate (DMAD) (0.6 mmol) catalyzed by pyridine or DMAP (20 mol %), we found that (E)-2-aryl-but-2-enedioic acid dimethyl ester 1 or (E)-2-[aryl-(toluene-4-sulfonylimino)methyl]-but-2-enedioic acid dimethyl ester 2 was formed in good yields at 60 degrees C in THF. A plausible mechanism has been proposed.     

Platinum Nanosheets Intercalated into Natural and Artificial Graphite Powders

Insertion of sheet-type platinum particles (platinum nanosheets) between graphite layers was achieved by a thermal treatment of a mixture of platinum chloride (IV) and graphite powder (natural graphite or artificial graphite) under 0.3 MPa of chlorine at 723 K, followed by the treatment under 40 kPa of hydrogen pressure. Similar platinum nanosheets, which were 1–3 nm in thickness and 100–500 nm in width and had a number of hexagonal holes and edges with 120° angle, were formed between the layers of both natural graphite or artificial graphite; however, their location in the graphite layers depended on the type of graphite used. A number of platinum nanosheets were observed in the edge region of natural graphite particles which have flat surface. On the other hand, a number of platinum nanosheets were found inside and away from the edge of the artificial graphite particles especially in the vicinity of the cracks. Both the platinum nanosheet-containing artificial and natural graphite samples showed high selectivity to cinnamyl alcohol in cinnamaldehyde hydrogenation under supercritical carbon dioxide conditions, while spherical platinum particles, which were located on the surface of natural and artificial graphite, showed lower selectivity.     

Totalsynthese von Betalainen

Total Synthesis of Betalaines cis-4-Oxo-2,6-piperidinedicarboxylic acid dimethyl ester ( 10 ) was transformed (44%) into the semicarbazone of 2,3-dihydrobetalamic acid dimethyl ester ( 13/14 ) by a modified Horner-Wittig reagent 12 . Oxidation of 13/14 afforded 41% of a mixture of stereoisomers of betalamic-acid-dimethyl-ester semicarbazone ( 4 ), key intermediate for the synthesis of betalaine pigments. The utility of 4 in this respect was demonstrated on a small scale by its conversion to the dimethyl ester of indicaxanthine ( 9 , 11%) and to the trimethyl ester of betanidine ( 7 , 87%). Hydrolysis of 7 gave betanidine ( 6 ). We further describe the synthesis of the trimethyl ester of an oxidized form of betalamic acid ( 20/21 ) as well as model condensation reactions on the carbonyl group of cyclohexanone, cis-4-oxo-2,6-diphenylpiperidine ( 23 ) and its N-formyl derivative 27 . Reaction of 4-oxo-1,2,3,4-tetrahydro-2,6-pyridinedicarboxylic-acid dimethyl ester ( 40 ) with acetic anhydride or with triethyloxonium tetrafluoroborate resulted in O-acylation or in O-alkylation along with dehydrogenative aromatization to yield the derivatives 39 or 42 , respectively, of chelidamic acid.     

食品包装材料中13种增塑剂的毛细管气相色谱法测定

建立了索氏提取、固相萃取净化浓缩、毛细管气相色谱法测定塑料食品包装材料中13种增塑剂的方法.优化了固相萃取淋洗剂、洗脱剂和洗脱剂体积等参数.样品经正己烷索氏提取后,用硅胶小柱净化浓缩.以正己烷-甲苯为淋洗剂,2 mL乙酸乙酯为洗脱剂.过滤后的洗脱液用气相色谱仪分析.结果显示,13种增塑剂在0.1～1000 mg/L范围...     

新型5-[10-(9-羧基蒽基)]-间苯二甲酸的合成及荧光性质

以5-氨基-间苯二甲酸二甲酯为原料,经重氮化溴取代、Miyaura硼酸酯化反应生成3,5-二甲氧羰基苯硼酸频哪醇酯(3)。此外,以9-蒽甲酸为原料,经溴化、酯化反应生成10-溴-9-蒽甲酸甲酯(6)。最后以化合物3和6为原料,经Suzuki偶联、水解反应得到目标化合物5-[10-(9-羧基蒽基)]-间苯二甲酸。其结构经1H NMR、13C NMR和高分辨质谱表征。研究结果表明,该化合物钠盐水溶液具有发蓝光的性质,最大发射波长为425nm,同时也有较好的荧光量子效率。     

Stability of Gold and Platinum Nanowires on Graphite Edges

The stability of coinage and noble metal nanowires supported on graphite steps is examined by density functional theory. In particular, we study the stability of supported gold and platinum wires and compare their chemical properties with those of surfaces and bare wires. A substantially stronger bond with graphite was found for platinum wires due to unfilled antibonding states, which are occupied in the case of gold. This difference has direct consequences for the adsorption of hydrogen. This reaction can occur either on the wire or directly on graphite steps. In the case of gold, the reaction is favoured on steps, while on platinum wires, it has no thermodynamical preferences. Our results suggest that, in early stages of wire formation, hydrogen could desorb gold from graphite, but not platinum.     

Platinum Nanosheets between Graphite Layers

Two‐dimensional platinum nanosheets were obtained by the hydrogen reduction of platinum tetrachloride intercalated between graphite layers, the latter was prepared by the treatment of the mixture of platinum tetrachloride and graphite powder under chlorine atmosphere. The size of platinum nanosheets was 1–3 nm in thickness with a width in the range of 5–300 nm. These nanosheets contain a number of hexagonal holes and edges with an angle of 120°. This review discusses the reduction and oxidation behavior of platinum species and structure of platinum nanosheets between graphite layers. The selective hydrogenation catalyzed by these platinum nanosheets entrapped between the graphite layers is also demonstrated.     

Synthesis of 2-Hydroxy-3-methyl-2-cyclo-pentenone,Corylone, from 2-Ketoglutaric Acid

Treatment of 2-ketoglutaric acid with diazomethane gave 2-(metoxycarbonyl)-oxiranepropanoic acid methyl ester (2) wich lead to 2-hydroxy-2-methyl-glutaric acid dimethyl ester (3) by catalytic hydrogenation, wich was further processed to the title compound.