超声波辅助提取辣木籽多酚工艺研究

采用福林酚法测定辣木籽中多酚含量,并确定福林酚法测定辣木籽多酚的适宜条件为:20%Na_2CO_3溶液1 mL、1 moL/L的福林酚试剂0.4 mL、反应温度60℃、反应时间30 min。通过响应曲面试验研究超声波辅助提取辣木籽多酚的最佳工艺条件为:乙醇体积分数74%、液料比19∶1(m L/g)、提取温度67℃、超声时间25 min。此条件下,辣木籽多酚的平均提取量为4.867 mg/g,该值与理论预测值4.889 mg/g基本一致。     

西藏红景天超临界流体萃取及萃取物的GC-MS分析

探讨了西藏红景天的超临界流体萃取工艺,应用GC-MS方法对萃取物成分进行了分析.结果表明,最佳提取工艺条件为:夹带剂乙醇的体积分数为85%,萃取温度为55℃,萃取压力为30 MPa,萃取时间为2 h.此条件下红景天萃取物得率为5.65%.GC-MS分析鉴定出32种组分,主要为醇类、酯类、烷烃、烯烃等化合物,并应用峰面积归一化法测定了其相对含量.     

顶空固相微萃取-气质联用分析小麦储藏过程中挥发性成分变化

采用顶空固相微萃取(HS-SPME)和气相色谱-质谱联用(GC-MS)对不同储藏时间弱(强)筋小麦中的挥发性物质进行提取、鉴定与分析.选用复合萃取纤维二乙烯基苯-炭烯-聚二甲硅氧烷共聚物(DVB/CAR/PDMS)50 μm涂层,对萃取温度、时间、样品用量和解析时间进行优化.结果表明: HS-SPME测定挥发性物质的最佳前处理条件样品量20 g, 萃取温度75 ℃, 萃取时间60 min, 260 ℃条件下解析5 min;经鉴定分析小麦挥发性成分主要有烃类、醛类,其次为醇类、酮类;挥发性成分总含量在储藏6个月内均呈现先降后增的趋势.弱筋小麦的烃类挥发物相对量随储藏时间延长而快速增加,醛类相对含量先降后升,而酮类和醇类相对含量则逐渐下降;强筋小麦中除烃类相对含量呈先下降而后快速增加外,其余各类挥发物含量均与弱筋小麦呈现相同的规律.储藏6个月后,变化较明显的挥发性物质有己醇、己醛、2,6,10-三甲基-十二烷、十五烷和二十烷.     

超临界萃取蝼蛄脂肪酸成分及其气相色谱-质谱分析

采用超临界CO2萃取蝼蛄总脂肪酸,对影响萃取效果的各个因素应用正交设计试验,优化了各萃取参数.各个因素的影响顺序为压力＞温度＞时间＞流量.萃取的优化条件为压力35 MPa,温度50℃,时间1 h,流量45 kg/h.运用该萃取条件改善了萃取物的物理性状,脂肪酸的纯度提高,总脂肪酸的含量可达83.29%;而采用常规的有机溶剂提取法,脂肪酸的纯度仅为60%左右.甲酯化采用气相色谱-质谱分析技术对其中的16个成分进行了鉴定,并测定了相对含量,其中主要有油酸甲酯(30.40%)、十六烷酸甲酯(14.19%)、9,12-十八碳二烯酸甲酯(11.99%)、油酸乙酯(11.75%)、9-十六碳烯酸甲酯(7.77%)、十六烷酸乙酯(5.97%)、9,12-十八碳二烯酸乙酯(4.53%)及9-十六碳烯酸乙酯(2.87%)等.     

藜蒿中黄酮类化合物的微波辅助萃取研究

应用密闭微波萃取装置，分别对藜蒿茎和藜蒿叶中黄酮类化合物进行微波萃取研究。采用正交试验方法得到微波提取藜蒿中黄酮类化合物的最佳条件。微波提取藜蒿茎的最佳条件为乙醇体积分数70％，微波功率800W，提取温度80℃和料液比1：20；微波提取藜蒿叶的最佳条件为乙醇体积分数70％，微波功率600W，照射时间12min，提取温度70℃和料液比1：20；在最佳条件下，藜蒿茎和叶中总黄酮提取率分别为6．43％和7．01％。并将微波萃取与乙醇回流提取进行了比较。     

微波辅助萃取新鲜芦荟叶中芦荟甙的研究

应用密闭微波萃取装置对芦荟中的有效成分芦荟甙进行了微波萃取研究,并利用透射电子显微镜对微波萃取机理进行了初步探讨.讨论了不同萃取剂、溶剂浓度、萃取时间和微波功率等对提取率的影响.在萃取剂为乙醇-水体系,溶剂(乙醇)体积分数为70%、萃取时间为4min及微波功率为340W的条件下,萃取效果最佳.与索氏提取及超声波萃取法相比,本法具有萃取速度快、提取率高及溶剂用量少等特点.     

采用超临界CO_2萃取技术提取废次烟叶中的茄尼醇

采用超临界CO2萃取技术提取废次烟叶中的有效成分茄尼醇,以乙醇为夹带剂,研究了萃取压力、萃取温度、CO2的流量、萃取时间、夹带剂的使用、分离温度和原料粒度等方面对萃取效果的影响,并对其中影响较为显著的因素进行了正交试验,通过极差和方差分析确定了萃取体系适宜的工艺条件。萃取压力为20 MPa,萃取温度为45℃,CO2的流量为15 L/h,萃取时间为2 h,夹带剂为95%的乙醇,分离温度为40℃,原料粒度为40~60目。     

密闭微波辅助萃取丹参中有效成分的研究

应用具有压力控制附件的MSP-100D密闭微波萃取装置,对丹参中的有效成分丹参酮、丹参酮A及隐丹参酮进行微波萃取研究.在乙醇体积分数为90%,微波辐射时间为4min,溶剂体积对样品质量比为20∶1和样品粒径为120目的条件下,有效成分提取率最佳.对比了密闭微波萃取同索氏萃取和超声萃取丹参有效成分的差异.     

水中农药多效唑的新型相膜微萃取富集测定

利用C18固相萃取膜和小玻璃磁子自制固相膜微萃取搅拌棒,首次建立了测定小体积水样中农药残留的样品处理技术.优化了萃取和解析条件,最佳条件:样品体积35 mL;萃取温度30℃;搅拌速率900 r/min;萃取时间和解析时间均为120 min,解析溶剂为甲醇,体积0.45 mL.方法的检出限为0.8μg/L(S/N=3).检验了该方法的准确度和精密度(RSD小于5%).在此条件下测定了黄河水中多效唑的含量,结果证明黄河水中该物质的残余量在检出限以下.     

响应面法优化微波提取翻白草总黄酮

利用响应面法研究了翻白草总黄酮的微波辅助提取工艺.在单因素试验的基础上,以乙醇体积分数、液固比、提取温度、微波时间为自变量,总黄酮的得率为响应值,研究各因素及其交互作用对黄酮得率的影响.结果表明其最佳提取条件是:乙醇体积分数55%、液固比32 m L/g、温度82℃、微波时间10 min.此条件下,翻白草中黄酮的提取率为6.96 mg/g,与理论预测值基本吻合.     

Clean synthesis of biodiesel over solid acid catalysts of sulfonated mesopolymers

FDU-15-SO₃H, a solid acid material prepared from the sulfonation of FDU-15 mesoporous polymer, has been demonstrated to serve as an efficient catalyst in the esterification of palmitic acid with methanol as well as in the transesterification of fatty acid-edible oil mixture. FDU-15-SO₃H achieved an acid conversion of 99.0% when the esterification was carried out at 343 K with a methanol/palmitic acid molar ratio of 6:1 and 5 wt% catalyst loading. It was capable of giving 99.0% yield of fatty acid methyl esters (FAME) when the transesterification of soybean oil was performed at 413 K and the methanol/oil weight ratio of 1:1. FDU-15-SO₃H was further applied to the transesterification/esterification of the oil mixtures with a varying ratio of soybean oil to palmitic acid, which simulated the feedstock with a high content of free fatty acids. The yield of FAME reached 95% for the oil mixtures containing 30 wt% palmitic acid. This indicated the sulfonated mesopolymer was a potential catalyst for clean synthesis of fuel alternative of biodiesel from the waste oil without further purification.     

用于生物柴油清洁生产的磁性固体催化剂CaO/MgO/Fe_3O_4

制备了具有磁性和催化活性的双功能催化剂CaO/MgO/Fe3O4,用于催化花生油酯交换制备生物柴油的清洁生产过程。对CaO/MgO/Fe3O4进行了XRD、TEM、FT-IR和磁性等表征分析,探讨了CaO/MgO/Fe3O4催化剂的重复利用性能。结果表明,用Mg(Ac)2溶液等体积浸渍磁性基质Fe3O4,在N2气氛中600℃焙烧2 h,可得到具有磁性的载体5%MgO/Fe3O4;再用Ca(Ac)2溶液等体积浸渍MgO/Fe3O4,并在N2气氛中700℃煅烧,得到具有磁性且催化活性较高的催化剂10%CaO/MgO/Fe3O4。该催化剂具有核壳结构,磁核平均直径约为35 nm。在催化剂用量10%,醇油摩尔比12∶1,反应温度65℃,反应2 h的条件下酯交换转化率可达90%以上。在磁场的吸引下该催化剂能快速与反应体系分离,催化剂回收率达90%。但CaO/MgO/Fe3O4重复利用性能较差,其原因是在搅拌反应过程中催化活性组分逐渐从催化剂上脱落所致。     

CaO-MgO@CoFe_2O_4磁性固体碱的制备及其大豆油酯交换反应催化性能

以草酸盐为前驱体采用两步法制备了一种以CaO-MgO作为活性组分,以CoFe_2O_4作为磁核的磁性固体碱催化剂,并用于大豆油与甲醇的酯交换反应合成生物柴油。对制备的磁性固体碱催化剂进行了磁滞回线、X-射线衍射(XRD)、CO_2-TPD及透射电镜(TEM)表征。考察了不同核壳物质的量比、焙烧温度、反应温度、反应时间、醇油物质的量比以及催化剂用量等因素对大豆油转化为生物柴油产率的影响。结果表明,采用核壳物质的量比为1∶6、焙烧温度为700℃所制备的CaO-MgO@CoFe_2O_4催化剂,当醇油物质的量比为12、催化剂用量为大豆油质量的1.0%时,在65℃下反应时间3 h,生物柴油收率高达97.1%。该催化剂具有较好的重复利用性能,重复利用四次后生物柴油的收率仍可达90%。     

Fe-Ca磁性固体碱催化剂上菜籽油酯交换反应

采用原位沉淀法合成了双功能磁性固体碱催化剂CaO·γ-Fe₂O₃,用于催化菜籽油酯交换反应制备生物柴油。利用XRD、BET、TG-DTA、SEM和VSM对催化剂进行了表征,用ICP-AES对产物脂肪酸甲酯(FAME)中Ca、Fe残留量进行了测定。结果表明,Fe和Ca两种组分间有较好复合,催化剂显示出较好的磁学性能,饱和磁化率达到45.7emu/g,明显高于文献报道的磁性碱催化剂。在温和的反应条件(常压、64℃、催化剂加入量为油重的2.5%、醇油摩尔比15、转速750r/min)下,反应2h,重复使用前三次酯交换反应转化率都维持在95%左右。     

Transesterification of Soybean Oil Catalyzed by Calcium Hydroxide which Obtained from Hydrolysis Reaction of Calcium Carbide

Calcium carbide residue (CCR) was investigated in transesterification reaction of triglycerides to determine its viability as a solid catalyst for biodiesel synthesis. Literature survey showed that CCR has never been studied as a solid catalyst in the transesterification of triglyceride. The scope of the study includes the effects of CCR calcination temperature, calcination time, the alcohol/oil molar ratio, the catalyst amount (wt % of oil) and the reaction time. The relationship between chemical composition and catalytic activity of waste cement was also investigated. These CCR catalysts, thermally activated at 600 °C, can give rise to fatty acid methyl esters (FAME) purity higher than 99.5%, after 3 h of reaction, when oil/methanol molar ratio of 1/12 and 1 wt % of the catalyst were employed. Application of CCR as catalyst for biodiesel production in this study may not only provide a cost‐effective and environment friendly way of recycling CCR waste but also reduce hopefully the cost of biodiesel production.     

亚铁锌双金属氰化络合物固体催化剂催化合成生物柴油

Fe(Ⅱ)-Zn双金属氰化络合物固体催化剂用于一步催化酯交换和酯化反应制备生物柴油,具有易分离、流程简单,不受水毒性影响的优点。将水溶性金属氰化络合物亚铁氰化钾和金属化合物氯化锌反应,并结合有机配体叔丁醇制备了基于亚铁氰化锌的双金属氰化物络合物(DMC)。并研究了DMC固体催化剂催化菜籽油合成生物柴油过程中,助络合剂种类、催化剂用量、反应温度、醇油摩尔比、反应时间、体系中水和脂肪酸含量等因素对反应过程的影响。研究结果表明,在最佳实验条件下,甲酯产率最高可达98%。催化剂可循环使用,6次循环使用后回收率仍达93.45%,适宜工业化生产。     

双核碱性离子液体催化棉籽油酯交换制备生物柴油

采用两步法制备了五种新型咪唑类碱性双核功能化离子液体化合物,并考察了对棉籽油酯交换制备生物柴油的催化性能。结果表明,咪唑类碱性双核功能化离子液体具有很好的催化活性,其催化活性与阳离子中碳链长度有关。其中,双-(3-甲基-1-咪唑)亚乙基双氢氧化物离子液体的催化活性最好。催化剂量、反应时间、反应温度及醇油比对生物柴油中脂肪酸甲酯含量及选择性影响的研究发现,在催化剂用量为0.4%(质量分数),醇油摩尔比为12,反应温度为55℃,反应时间为4 h时,脂肪酸甲酯的含量和选择性分别达98.5%和99.9%。催化剂7次循环后,产物中脂肪酸甲酯含量仍达到96.2%,单甘酯和双甘酯的含量很少,表明该催化剂重复使用良好。     

钙基负载型固体碱催化酯交换反应活性评价

动植物油脂与醇通过酯交换反应制备生物柴油,目前,工业上一般采用NaOH、KOH、NaOCH,等均相催化剂。均相催化剂的缺点是产品后处理复杂,产生大量含碱含油工业废水。而非均相固体碱催化酯交换反应,产品与催化剂分离容易,产品不需要水洗,避免了大量废液的排放。采用非均相固体碱制备生物柴油的文献报道较多,但固体碱的碱中心数、碱中心强度对酯交换反应影响的报道较少。本研究制备了钙基负载型固体碱催化剂,重点研究钙基负载型固体碱的制备工艺条件对碱强度、碱量分布的影响,考察碱强度、碱量分布对催化菜籽油与甲醇的酯交换反应制备生物柴油转化率的影响。     

Preparation of biodiesel catalysed by KF/CaO with ultrasound

Biodiesel, chemically consists of fatty acid methyl ester (FAME) produced by methanolysis of natural triglycerides, such as animal fats and vegetable oils, is a kind of biomass energy, which is renewable and ecofriendly. In this article, KF/CaO was used as solid base catalyst for transesterification of soya bean oil and methanol, while ultrasound as supplementary means. Compared to mechanical stirring, ultrasound treatment is an effective method to increase the yield of FAME and shorten reaction time. By single-factor method, the optimisation of reaction conditions has been studied. The research showed that the optimum reaction conditions were: w(catalyst)/w(oil): 3%, reaction temperature: 65°C, n(methanol)/n(oil): 12, reaction time: 1?h, sound intensity: 1.01?W?cm(-2), frequency: 20?kHz, the yield of FAME could be 97%.     

Lipase-Catalyzed Transesterification of Rapeseed Oil for Biodiesel Production with tert-Butanol

Biodiesel is a fatty acid alkyl ester that can be derived from any vegetable oil or animal fat via the process of transesterification. It is a renewable, biodegradable, and nontoxic fuel. In this paper, we have evaluated the efficacy of a transesterification process for rapeseed oil with methanol in the presence of an enzyme and tert-butanol, which is added to ameliorate the negative effects associated with excess methanol. The application of Novozym 435 was determined to catalyze the transesterification process, and a conversion of 76.1% was achieved under selected conditions (reaction temperature 40 °C, methanol/oil molar ratio 3:1, 5% (w/w) Novozym 435 based on the oil weight, water content 1% (w/w), and reaction time of 24h). It has also been determined that rapeseed oil can be converted to fatty acid methyl ester using this system, and the results of this study contribute to the body of basic data relevant to the development of continuous enzymatic processes.