糠醛合成富马酸二甲酯

提出了一种合成富马酸二甲酯（ＤＭＦ） 的新方法。以糠醛为原料,先用氯酸钾作氧化剂氧化制得富马酸,再用磷钨酸作催化剂与甲醇进行酯化制得富马酸二甲酯,总产率可达７３％ 。研究了催化剂用量、原料配比、反应温度、反应时间对产率的影响。确定了最佳工艺条件：（１） 糠醛１０ ｍＬ,氯酸钾２５ ｇ,五氧化二钒０－１ ｇ,在１０５ ℃下,搅拌回流反应４ ｈ,富马酸的产率可达８２％ ;（２） 富马酸５ ｇ,甲醇１０ ｍＬ,磷钨酸１－５ ｇ,回流反应４ ｈ,ＤＭＦ的产率可达８９ ％ 。     

稀土固体超强酸SO_4~(2-)/TiO_2/La~(3+)催化合成富马酸二甲酯

以固体超强酸ＳＯ_４~(２－)／ＴｉＯ_２／Ｌａ~(３＋)为催化剂,富马酸和甲醇为原料合成富马酸二甲酯,考察了影响反应的因素。结果表明：ｎ（醇）：ｎ（酸）＝６：１;催化剂用量为对０．１ｍｏｌ富马骏耗１．０ｇ催化剂,二氯甲烷为溶剂;在回流温度下反应４ｈ,酯化率达９４％以上。     

DL-天冬酰胺合成工艺研究

在一内衬钛材的不锈钢高压釜中,采用自制的Ｎ 催化剂,通过马来酸酐氨解反应合成了ＤＬ 天冬酰胺。对影响反应收率的原料配比、反应温度和反应时间以及催化剂的用量进行了研究。所得最佳合成条件如下：氨水与马来酸酐物质的量比为１０．２∶１,反应时间５ ｈ,反应温度９０℃,催化剂Ｎ与马来酸酐质量比为０．１５∶１。在最佳工艺条件下,产品总收率为７０ ％ ,纯度达到９９％ 。并通过ＩＲ光谱对产品进行了验证。     

顺丁烯二酸合成富马酸二甲酯

提出了一种合成富马酸二甲酯（ＤＭＦ）的新方法：以顺丁烯二酸为原料,先用过硫酸铵作催化剂制得富马酸,再用磷钨酸作催化剂与甲醇进行酯化制得富马酸二甲酯。确定了最佳工艺条件：富马酸０．７５ｍｏｌ,甲醇７．５ｍｏｌ,磷钨酸０．０７５ｍｏｌ,回流反应１０ｈ,ＤＭＦ收率可达９４．２％。     

富马酸二甲酯的合成研究

讨论了富马酸二甲酯合成的最佳反应条件，确定为：富马酸：甲醇＝１：６（摩尔比），催化剂浓硫酸用量为富马酸的１０％，溶剂水的用量为甲醇的９％（体积比），富马酸二甲酯的产率达９２．４％，并用红外光谱和ＨＰＬＣ对产品进行了分析。     

富马酸二甲酯的催化合成

以SnCl4·5H2O为催化剂,用马来酸酐和甲醇为原料合成富马酸二甲酯.酯化反应的工艺条件:SnCl4·5H2O 1.0g,马来酸酐与甲醇物质的量比为1:6,回流反应时间3.0h,收率达84.2%.     

由糠醛合成富马酸

以糠醛为原料,氯酸钾为氧化剂合成富马酸,研究了反应物配比、反应温度、反应时间对产率的影响。确定了最佳工艺条件：糠醛１０Ｌｍ,氯酸钾 ２５ ｇ,五氧化二钒０．２ｇ,在１０５℃搅拌回流４ｈ,富马酸的产率可达８２％。     

富马酸二甲酯的合成研究

讨论了富马酸二甲酯合成的最佳反应条件,确定为：富马酸∶甲醇＝１∶６（摩尔比）,催化剂浓硫酸用量为富马酸的１０％,溶剂水的用量为甲醇的９％（体积比）,富马酸二甲酯的产率达９２．４％,并用红外光谱和ＨＰＬＣ对产品进行了分析。     

一锅法合成富马酸二甲酯

以马来酸酐和甲醇为原料,以HCl／H3PO4作催化剂。通过精馏分水-锅法制备富马酸二甲酯,考察了醇酐比、酯化时间和异构化温度对产率的影响,确定了最佳反应条件为：醇酐物质的量比为6：1,回流反应6h．异构化温度为100℃,利用红外谱图和元素分析对产物进行了表征。     

富马酸二甲酯的合成

马来酸酐与甲醇在混合催化剂的作用下,一步合成了富马酸二甲酯。确定了最佳工艺条件:三氯化铁0 5g,浓硫酸1 0ml,浓磷酸2 0ml,硫脲1 0g,溴化钠1 0g,马来酸酐4g及甲醇,回流反应2h,产率达88%,产品纯度大于99%。该法具有操作简便、反应时间短的特点。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。