微波辅助抽提煤的实验研究

在微波辅助下,以四氢呋喃、乙醇和乙酸为溶剂抽提神府煤,考察了抽提温度、抽提时间、溶剂用量及煤粒度对抽提率的影响;同时探讨了上述三种溶剂对不同变质程度的攀枝花煤、铜川煤、神府煤、华亭煤和依泰煤在微波辅助下的抽提效果.结果表明,抽提率在一定的抽提温度、时间、溶剂用量及煤粒度下均有最佳值;变质程度相似的煤在相同抽提条件下抽提率不同.运用红外光谱现代分析技术,对神府脱灰煤和其抽提残煤的结构特征进行了对比分析,结果表明,抽提并没有破坏煤的大分子结构;利用GC/MS测定了铜川煤的乙醇微波辅助抽提物的组成.     

温度对神府煤微波辅助萃取影响的实验研究

为进一步研究温度对微波辅助萃取(microwave-assisted extraction,MAE)的影响,采用四氢呋喃作为萃取溶剂,在不同温度水平下对神府煤进行了微波辅助萃取实验研究。结合柱层析分离和傅立叶红外光谱(FTIR),分别定量半定量分析研究了萃取温度对萃取物组成及萃取残煤化学结构的影响。结果表明:随着萃取温度的增加,神府煤的MAE萃取率在140℃下达到最高值,并在150℃左右受到活性含氧化合物(主要为萃取物极性组分)裂解反应的影响。随着萃取温度从100℃增加至140℃,萃取残煤中脂肪族化合物含量比芳香族化合物含量受萃取温度影响更为明显,而MAE萃取率则与萃取残煤中含氧官能团C=O与C—O的相对含量之比(β)存在反相关关系,这表明温度的升高明显促进了溶质内含C=O官能团与溶剂的溶剂-溶质相互作用。     

微波辅助萃取煤的实验研究

在微波辅助下,以神府煤为主要研究对象,四氢呋喃、丙酮、甲醇为溶剂,考察了萃取温度、时间、溶剂量及煤粒度对萃取率的影响,结果显示:使上述3种沸点接近的不同溶剂萃取率达到最佳值,所需要的萃取温度、溶剂量及煤粒度相差大;同时探讨了以四氢呋喃、丙酮、N,N-二甲基甲酰胺为溶剂,对不同变质程度煤的微波辅助萃取效果,结果是变质程度相似的煤在相同萃取条件下萃取率不同。运用红外光谱现代分析技术,对神府脱灰煤和四氢呋喃抽提残煤的结构进行对比分析,结果表明萃取并没有破坏煤的大分子结构。     

神府煤的液化性能及其重质产物结构表征

利用管式高压反应釜,以四氢萘为溶剂、FeS和S为催化剂,对神府煤进行了加氢液化研究,考察了催化剂、反应温度和反应气氛等因素对煤液化性能和产物组成分布的影响,同时对液化产物进行了红外光谱、元素分析以及酸性含氧官能团等结构表征。结果表明,FeS+S催化神府煤液化的最高四氢呋喃(THF)抽提率和油+气收率分别为69.5%和35.9%;未加催化剂时,神府煤液化THF抽提率和油+气收率都是最低的。     

褐煤腐植酸的抽提及其对褐煤吸水性能的影响

褐煤腐植酸含量高,腐植酸中含有多种活性基团,在工业、农业、畜牧业等领域有多种用途。褐煤直接燃烧利用率不大,因此在开发利用褐煤资源前对其进行腐植酸抽提是一种较好的提质方式。本文采用碱浸法对褐煤进行腐植酸的抽提,研究了煤样粒度、抽提条件等因素对腐植酸抽提率的影响,以及干燥的原煤、腐植酸抽提残煤和脱灰煤的水分复吸性能。结果表明:粒度在0.2mm以下的煤样,在超声波条件下抽提腐植酸效果较好;抽提残煤水分复吸率明显高于原煤,但将抽提残煤脱灰处理后,水分复吸率有明显下降,且与原煤脱灰后吸水性能相近,说明抽提残煤的吸水性与煤的孔隙率及表面的极性官能团有关,特别是碱浸法抽提腐植酸时生成的强吸水性羧酸盐类对抽提残煤吸水性有显著影响。     

两种萃余煤的温和氧化产物的组成分析

分别用二硫化碳 ( CS2 ) /四氢呋喃 (体积比 1∶ 2 )混合溶剂和环己酮对义马煤和美国Pocahontas No.3( P3)标准煤样进行了彻底萃取 ,在 60℃下用 30 %双氧水溶液分别氧化了所得的两种萃余煤 ,用 GC/MS对反应混合物中的水溶液的苯可溶物和水不溶物的 CS2 可溶物进行了分析 .结果表明 :在所得水溶液的苯可溶物中都检测出苯酚 ;在由义马萃余煤氧化所得的水不溶物的CS2 可溶物中检测出多种含氧有机化合物和长链烷烃 ,而在 P3萃余煤氧化所得的水不溶物的 CS2可溶物中只检测到一系列长链烷烃 .     

神府镜煤光氧化产物的组成和结构研究

在紫外光照射下,用氧气对神府镜煤进行了光催化氧化研究。探讨了氧化时间对氧化煤中腐植酸含量的影响。通过溶剂抽提,FTIR分析及GC/MS分析对神府镜煤光氧化产物进行了组成和结构分析。研究表明:控制光氧化时间,可以获得不同腐植酸含量的光氧化产物,在光氧化4 h时,镜煤中腐植酸含量最高;镜煤在光氧化产物过程中,芳香结构较难打开,主要是醚键等含氧官能团发生反应,生成羧基和甲基等。     

神府煤石油醚萃取物组成及萃取过程分析

采用自行研制的萃取系统对神府煤进行了石油醚溶剂萃取,并结合GC/MS技术对萃取物进行了定性和定量分析,讨论了萃取物的化学组成及其萃取过程.结果显示,神府煤石油醚萃取物的GC/MS可测组分主要由脂肪烃、芳烃及含氧杂原子化合物组成,其中含氧化合物相对含量达到72%;各次循环萃取量经历了从低到高、再从高到低的过程;各分子化合物在溶剂中的溶解析出规律有较大差异.     

神府煤甲醇萃取物的GC/MS及FTIR分析

用GC/MS和FTIR技术结合气相色谱外标定量分析方法,对神府煤甲醇萃取物进行了定性和定量分析,讨论了神府煤甲醇萃取物的化学组成及其结构特征.结果显示,神府煤甲醇萃取物的GC/MS可测组分主要由多环芳烃和含氧化合物组成,其中芳烃以2～3环的烷基取代稠环芳烃为主,含氧化合物中以酮类和酯类化合物居多;结果还检测到种类较多的含氮化合物和少量的含硫、磷、氯的化合物.GC/MS不可测组分的IR分析显示,其中主要官能团有各类羟基、羰基、芳环和亚甲基、甲基等,表明其中可能存在分子量较大的稠环芳香族或其酚、酸、酮、酯类及烷基衍生物的化合物.     

义马萃余煤NaOCl氧化产物的GC/MS分析

用四氢呋喃/二硫化碳混合溶剂对义马煤进行了彻底萃取.在超声波辐射条件下用次氯酸钠水溶液氧化所得的萃余煤,用GC/MS对从反应混合物分离所得的水溶液中的苯可溶物进行了分析.结果表明,在该苯可溶物中共鉴定出16种有机化合物,其中蒽的含量高达85%,其次是棕榈酸、蒽酮和蒽醌,含量各为3%左右,其他化合物的含量都小于1%.     

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.     

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。     

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…     

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。