正交设计优化石韦多糖的纤维素酶法提取工艺

采用单因素试验和正交试验,以石韦多糖得率为指标,研究pH值、酶用量、酶解温度和时间对石韦多糖提取效果的影响。优选纤维素酶法提取石韦多糖的工艺条件。正交试验结果表明,影响石韦多糖得率的因素次序:酶解温度酶解pH值酶解时间酶用量。得出纤维素酶法提取的最佳工艺条件为:酶解pH6.0,酶用量为8.0mL,酶解温度50℃,酶解时间50min。在优化的条件下进行提取实验,石韦多糖得率为6.58%。说明纤维素酶法提取石韦多糖省时高效,可为石韦多糖的大规模生产提供可借鉴的新方法。     

复合酶协同超声提取葫芦巴中薯蓣皂苷的工艺研究

研究复合酶协同超声提取葫芦巴中薯蓣皂苷的工艺。以葫芦巴中薯蓣皂苷得率为考察指标,通过单因素试验及L_9(3~4)正交试验,探讨纤维素酶、果胶酶复合酶制剂的使用量、酶解时间、酶解温度、pH值对薯蓣皂苷得率的影响,优化复合酶协同超声提取葫芦巴中薯蓣皂苷的工艺条件。结果表明,最佳酶解条件为复合酶制剂用量为2.5%,酶解温度为30℃,pH值为6.0,酶解时间为2h。在此条件下,葫芦巴中薯蓣皂苷的得率为2.29%,经比较,复合酶协同超声提取薯蓣皂苷的得率比直接超声提取增加了36.3%。     

SFP-AQ法预处理麦秸秆对酶解还原糖得率的影响

用SFP-AQ法(亚硫酸钠和甲醛―蒽醌)预处理麦秸秆,研究预处理条件对酶解还原糖得率的影响。结果表明,较适宜的预处理和酶解条件分别为:蒸煮温度150℃,保温时间1 h,Na2SO3用量为12%,纤维素酶、木聚糖酶、β-纤维二糖酶三种复合酶用量为20 FPU/g,pH值4.8,酶解温度50℃,酶解时间48 h。此时,还原糖得率可达到46.4%。     

响应面法优化莲子壳中黄酮类物质的提取工艺

利用酶辅助法对莲子壳中总黄酮的提取工艺进行优化。在单因子试验结果的基础上,采用响应面法研究了酶用量、酶解时间、p H值和酶解温度对莲子壳中总黄酮提取得率的影响。结果表明:纤维素酶具有较好的酶解能力,当酶用量为6.5 mg/g,酶解时间为1.5 h,p H 4.7,温度为46℃时,总黄酮得率达到7.1%。     

正交实验优化酶解预处理提取银杏叶黄酮和内酯的工艺

采用酶法预处理银杏叶,考察酶用量、酶解时间、酶解温度、pH值对银杏叶总黄酮和总内酯提取率的影响。结果表明,采用复合酶(纤维素酶∶果胶酶=1∶1)、用量为银杏叶的1/300、酶解4.0 h、温度50℃、初始pH为5.0时酶解效果最佳,该工艺条件下,总黄酮提取率为92.38%,总内酯提取率为91.74%。     

正交实验优化酶解预处理提取银杏叶黄酮和内酯的工艺

采用酶法预处理银杏叶,考察酶用量、酶解时间、酶解温度、pH值对银杏叶总黄酮和总内酯提取率的影响。结果表明,采用复合酶(纤维素酶∶果胶酶=1∶1)、用量为银杏叶的1/300、酶解4.0 h、温度50℃、初始pH为5.0时酶解效果最佳,该工艺条件下,总黄酮提取率为92.38%,总内酯提取率为91.74%。     

复合酶法提取白术多糖的工艺研究

研究了复合酶(纤维素酶和果胶酶)提取白术多糖的最佳工艺条件。分别比较了酶解温度、酶解pH、酶解时间以及酶量对多糖提取率的影响。并采用正交设计优化提取条件,确定最佳提取工艺:酶解温度为50℃,酶解pH为5.0,酶解时间为50 min,复合酶量为0.7%。在最佳提取工艺下,多糖的得率为43.00%。     

SFP-AQ法预处理麦秸秆酶解葡萄糖得率的变化规律

对SFP-AQ法(亚硫酸钠和甲醛―蒽醌)预处理麦秸秆酶解葡萄糖得率进行了研究。结果表明:葡萄糖得率随着预处理中Na2SO3用量的增加先升高后降低,在12%时葡萄糖得率最高;葡萄糖得率随着酶用量的增加而迅速升高,当酶用量超过20 FPU/g时,提高缓慢;蒸煮最高温度和保温时间对葡萄糖得率的影响不明显。较适宜的预处理和酶解条件分别为:蒸煮最高温度150℃,保温时间1 h,Na2SO3用量为12%,纤维素酶、木聚糖酶、β-纤维二糖酶三种复合酶用量为20 FPU/g。此时,葡萄糖得率可达到31.7%,酶解葡萄糖对原料中葡萄糖的转化率为91.6%。     

纤维素酶法提取葶苈子多糖的工艺研究

优化纤维素酶法提取葶苈子多糖及其纯化。通过单因素实验和正交实验,研究酶解温度、提取时间、酶用量和pH值对葶苈子多糖提取率的影响,并经脱脂、热水抽提、乙醇沉淀、Sevage法脱蛋白得到葶苈子多糖。纤维素酶法提取的优化工艺条件为:pH值为5,加酶量4mL,酶解温度50℃,提取时间1h。在此条件下,葶苈子多糖的提取率平均为4.8%,RSD为0.12%。纤维素酶法提取葶苈子多糖省时高效,多糖的纯化方法简便,易操作,纯度高。     

银杏黄酮的酶法提取工艺研究

研究了银杏叶中黄酮的酶法提取工艺,银杏叶原料经纤维素酶预处理后浸提,总黄酮得率显著提高,对叶得率可达到2.01%。其酶解过程的最优参数为:料液中酶的质量浓度为0.125g/L,酶与底物配比为1∶1200,酶解温度45℃,自然pH值,酶解时间2h。     

In-situ monitoring of the stabilization with hydrogen of free radicals thermally induced from coal using high pressure e.s.r., d.t.a. and p.d.a. equipment

High temperature, high pressure e.s.r. measurements of the hydrogenation reaction of Taiheiyo coal in the presence of catalysts were carried out to understand the stabilization of thermally and/or catalytically induced free radicals. A decrease in free radical concentration with increasing temperature was observed for ZnCl₂ and SnCl₂ · 2H₂O catalysts at 10MPa under hydrogen gas. High pressure modified single-cell d.t.a. and p.d.a. equipment augmented the uniquely designed high temperature, high pressure e.s.r. cell. The hydrogenation reaction was monitored under the same experimental conditions as for e.s.r. From the results of the combination of high temperature, high pressure e.s.r. with high pressure d.t.a. and p.d.a., it was established that H₂ molecules can react efficiently with free radicals from coal molecules created by the presence of ZnCl₂ and SnCl₂ · 2H₂O catalysts.     

Characterisation of separated melamine—formaldehyde adducts (methylolmelamines) and adduct mixtures by h.p.l.c. and by n.m.r. and u.v. spectroscopy

Most of the individual methylolmelamines that occur in melamine–formaldehyde adduct mixtures have been separated by preparative high-performance liquid chromatography (h.p.l.c.) and recovered in amounts sufficient to allow their characterisation by high-field ¹H- and ¹³C-n.m.r. Particular attention has been paid to the chemical shifts of the aromatic azine carbons of the melamine nuclei. These carbon shifts are shown broadly to be in agreement with some values previously published, but additional assignments have been made. It is shown that a satisfactory quantitative analysis of the methylolmelamines in a melamine–formaldehyde adduct mixture can be carried out either by h.p.l.c. or by ¹³C-n.m.r.     

Two-dimensional n.m.r. characterization of cycloaliphatic epoxy resins

The cycloaliphatic epoxy resins were studied by various two-dimensional nuclear magnetic resonance (2D n.m.r.) spectroscopies. The ¹³C n.m.r. spectra of the epoxy resins were assigned by using DEPT and 2D INADEQUATE techniques and the ¹H n.m.r. spectra were assigned by using 2D ¹H---¹H and ¹H---¹³C COSY techniques. Complete characterization of the samples synthesized by the oxidation of cyclohexene derivatives not only revealed the existence of the stereochemical isomers resulting from the structural difference of the oxide rings in the samples but also provided the composition ratio of the isomers.     

E.s.r. spectra of eastern oil shales

E.s.r. spectra of several oil shales from eastern and western USA have been measured at 9 and 25 GHz. The spectra of the western shales were similar to previously reported spectra and consist of a Mn²⁺ signal and a featureless organic signal. The eastern spectra consist of a V⁴⁺ signal and a complex and unusual organic signal consisting of at least four component signals. The organic signal has been characterized in terms of g factor, line-width and saturation characteristics. The effect of oxygen on the signal has also been examined. Electron nuclear double resonance (ENDOR) signals have been obtained from the organic signals of the eastern oil shales.     

Evaluation of a delayed coking process by H and C n.m.r. spectroscopy: 2. Detailed interpretation of liquid n.m.r. spectra

The ¹H and ¹³C nuclear magnetic resonance (n.m.r.) spectra of a delayed coking feedstock and products, presented in a previous paper, are analysed here in detail by matching results from inspection of both nuclei. The conventional spectra of whole samples are used in combination with elemental analysis data, and substantial agreement is obtained. Differences are explored to yield valuable information. Interpretation of some band assignments is modified to account for new results. This approach results in a detailed quantitative estimation of a few key structures that contain the main functional groups that characterize these petroleum fractions.     

An h.p.l.e. and m.s. analysis of distillate fractions of neutral oil from hydrogenated Akabira coal to elucidate chemical structures

Akabira coal-derived neutral oil was separated into 25 narrow boiling range fractions covering 183–423 °C, and subsequently separated into compound class fractions : alkanes, monoaromatics, naphthalene-type diaromatics, fluorene-type diaromatics and tri- and/or tetraaromatics, by high performance liquid chromatography (h.p.l.c.). The compound type analyses of the distillate/h.p.l.c. fractions were performed using electron impact mass spectroscopy (e.i.m.s.) or field ionization mass spectroscopy (f.i.m.s.). Aromatic/hydroaromatic compound types and the alkyl side-chain carbon distribution of the distillate/h.p.l.c. fractions were clarified, based on the separation behaviour of h.p.l.c. and the type analyses according to Z value by m.s. By the distillation/h.p.l.c./m.s. method, coal-derived oil was characterized in terms of the distribution of the numbers of aromatic rings, naphthenic rings and carbons of alkyl groups attached to these rings. The variations in chemical structure in a compound class with distillation temperature are discussed in terms of these chemical structural factors.     

活性染料SEFR值与中性固色工艺研究

根据活性染料染色特征值S．E．F．R．选择适用于中性固色工艺的活性染料，结果表明，S值高和低的活性染料对碱的浓度和温度敏感，对固色率的影响较为杂乱，但在温度为80℃时，这类染料的固色率均达到峰值：染色特征值在50-60范围内的活性染料适用于中性固色、以甲酸钠为中性固色剂对活性染料进行中性固色实验，其固色率均可达到60%左右．各项牢度均达到标准。最佳工艺条件为：甲酸钠：15g／L；尿素：20g／L；双氰胺10g／L，固色温度85℃：浴比：1：20。     

Structural characterization of Saudi Arabian heavy crude oil by n.m.r. spectroscopy

Saudi Arabian heavy crude oil was separated into six fractions, including five distillate fractions (<93, 93–204, 204–260, 260–343 and 343–454 °C) and a >454 °C distillation residue. Each fraction was analysed by ¹H and ¹³C n.m.r. spectroscopy, and combined gained information from these analyses provided reliable average structural parameters. These included estimation of aliphatic and aromatic content, average paraffinic chain length, and estimation of hydrogen, methyl and alkyl bearing aromatic carbons for each of the six fractions. The extent of branching in paraffinic chains and amount of aromatic bridgehead carbons were also calculated.     

13C n.m.r. study of raw materials for carbon black

¹³C n.m.r. spectroscopy has been applied to investigate a number of coal tar and petroleum-derived carbon black feedstocks. Application of the J-modulated spin echo technique is especially rewarding, as this method renders the quaternary carbons directly detectable. Thus the quality of carbon black feedstocks can additionally be gauged on the basis of the contents of quaternary carbons, which is a direct indication of the carbon yield in the carbon black production process.     

E.p.r. studies of outburst-prone anthracite coal

Changes in the macroscopic structure of coal have been observed as an outburst-prone area is approached. Associated with this structural change was an increase in the concentration of paramagnetic centres. Initial results suggested that this increase was not due to variation in maceral content within the coal samples but to the mechano-chemical degradation of the coal as a result of tectonic forces applied over geological time.