首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
几种固体催化剂催化油脂与甲醇酯交换反应性能的比较   总被引:5,自引:1,他引:5  
阎杰 《粮油加工》2005,(8):47-49
酶以及固体材料作为酯交换的催化剂是当前的研究热点。本文选择了几种具有代表性的固体材料作为油脂与甲醇酯交换的催化剂,对它们的催化活性进行了对比,结果显示,所有这些催化剂中,CaO的催化活性较强,在植物油与甲醇摩尔数比1∶6,65~66℃,催化剂CaO用量为油脂质量的2%的条件下,反应300min,转化率为95.5%。  相似文献   

2.
几种固体催化剂催化油脂与甲醇酯交换反应性能的比较   总被引:2,自引:0,他引:2  
酶以及固体材料作为酯交换的催化剂是当前的研究热点。本文选择了几种具有代表性的固体材料作为油脂与甲醇酯交换的催化剂,对它们的催化活性进行了对比,结果显示,所有这些催化剂中,CaO的催化活性较强,在植物油与甲醇摩尔数比1:6,65-66℃,催化剂CaO用量为油脂质量的2%的条件下,反应300min,转化率为95.5%。  相似文献   

3.
钙基固体碱催化酯交换反应制备生物柴油研究进展   总被引:4,自引:0,他引:4  
综述了近期氧化钙、钙化合物、负载型氧化钙等钙基固体碱催化剂用于酯交换制备生物柴油的研究进展。钙基固体碱具有较高的酯交换制备生物柴油催化活性,且原料来源广、价格相对较低,是一类具有前景的用于生物柴油清洁生产的固体碱催化剂。钙基固体碱催化剂在存放过程中易碳酸盐化而失去催化活性,生物柴油原料含水含酸量不但降低催化剂催化活性,而且增加催化剂回收难度、增加生物柴油产品中钙离子含量,在研究钙基固体碱催化剂催化酯交换反应机制的基础上,解决以上一系列问题,有助于钙基固体碱催化剂的工业化应用。  相似文献   

4.
采用溶胶-凝胶-浸渍法制备SO2-4/ZrO2固体酸催化剂,将其应用于环氧大豆油和甲醇的开环加成反应,系统考察了沉淀pH、H2SO4浸渍液浓度、焙烧温度对SO2-4/ZrO2固体酸催化剂催化活性的影响.采用XRD、NH3- TPD、氮吸附等方法对SO2-4/ZrO2催化剂的结构和表面酸性进行了表征.结果表明:催化剂的表面强酸位是促进开环加成反应得到大豆油基多元醇的催化活性中心.当沉淀pH为9,H2SO4浸渍液浓度为2 mol/L,焙烧温度为550℃时,催化剂表面具有更多的强酸中心,催化活性最高,110℃反应2h后,环氧大豆油中环氧基团转化率大于98%,大豆油基多元醇的羟值(KOH)达到203.7 mg/g,且产物易与催化剂分离,简化了后处理过程.  相似文献   

5.
合成了5种新型咪唑类和吡啶类双核酸性离子液体,并考察了其催化餐饮废油酯交换制备生物柴油的性能。实验表明,咪唑类双核酸性离子液体具有很好的催化活性,其中[MIM]2C3[HSO4]2催化活性最好。在以[MIM]2C3[HSO4]2为催化剂条件下,通过单因素实验和正交实验考察了醇油摩尔比、反应温度、反应时间和催化剂用量对酯交换反应的影响,并考察了双核酸性离子液体的稳定性。结果表明:在醇油摩尔比45∶1、反应温度170℃、反应时间2 h和催化剂用量为餐饮废油质量8%的条件下,生物柴油产率可达95.8%,并且该双核酸性离子液体的稳定性良好,循环使用6次后其催化活性没有明显降低。  相似文献   

6.
采用浸渍法制备了Cs2O/La2O3固体碱催化剂,并将其用于棉籽油与甲醇酯交换制备生物柴油的反应。考察了催化剂载体、Cs2O负载量、焙烧温度对催化剂活性的影响。结果表明:采用La2O3作为载体,Cs2O负载量20%(Cs2O与载体的质量比),焙烧温度600℃,制备得到的Cs2O/La2O3固体碱催化剂用于酯交换反应时具有良好的催化活性。在反应温度65℃,醇油摩尔比12∶1,固体碱催化剂用量为油质量的3%,反应3 h产物中棉籽油甲酯含量达到98.8%。  相似文献   

7.
微波-固体酸催化棉籽油制备生物柴油的研究   总被引:2,自引:0,他引:2  
探讨了微波辅助条件下采用新型固体酸S2082-/Al2O3-ZrO2-La2O3替代传统的液体酸、碱催化剂,催化棉籽油与甲醇进行酯交换反应制备生物柴油。考察了微波功率、固体酸催化剂用量、醇油摩尔比、反应温度等因素对产物中甲酯含量的影响。结果表明,在微波辅助下,固体酸催化剂对棉籽油酯交换具有较好的催化活性和稳定性,产物与催化剂易于分离。在微波功率300W,反应温度120℃,醇油摩尔比12:1,固体酸催化剂用量为油质量的3%条件下,反应1.5h产物中棉籽油甲酯含量达到95.2%,催化剂重复使用10次甲酯含量维持在90%左右,表明催化剂具有较高的催化活性和稳定性。  相似文献   

8.
固体酸催化剂催化乌桕籽油制备生物柴油   总被引:6,自引:1,他引:5  
以乌桕籽油为原料,对固体酸催化其与甲醇发生酯交换反应制备生物柴油进行了研究。通过对S2O8^2-/TiO2、S2O8^2-/TiO2-ZrO2、SO4^2-/TiO2-ZrO2、SO4^2-/AL2O3-ZrO24种固体酸催化剂的制备,并在同一条件下比较了它们在乌桕籽油制备生物柴油反应中的催化活性。结果表明,催化剂SO4^2-/TiO2-ZrO2表现出了较高的催化活性,SO4^2-/TiO2-ZrO2催化的最佳酯交换反应条件为:反应温度150℃,醇油摩尔比12:1,催化剂用量5%,反应时间6h,此时乌桕籽油的酯化率超过95%,且催化剂重复和再生使用效果良好。  相似文献   

9.
采用溶胶-凝胶-浸渍法制备SO42-/ZrO2固体酸催化剂,将其应用于环氧大豆油和甲醇的开环加成反应,系统考察了沉淀pH、H2SO4浸渍液浓度、焙烧温度对SO42-/ZrO2固体酸催化剂催化活性的影响。采用XRD、NH3-TPD、氮吸附等方法对SO42-/ZrO2催化剂的结构和表面酸性进行了表征。结果表明:催化剂的表面强酸位是促进开环加成反应得到大豆油基多元醇的催化活性中心。当沉淀pH为9,H2SO4浸渍液浓度为2 mol/L,焙烧温度为550℃时,催化剂表面具有更多的强酸中心,催化活性最高,110℃反应2 h后,环氧大豆油中环氧基团转化率大于98%,大豆油基多元醇的羟值(KOH)达到203.7 mg/g,且产物易与催化剂分离,简化了后处理过程。  相似文献   

10.
固体酸催化麻疯树籽油制备生物柴油   总被引:3,自引:0,他引:3  
采用新型固体酸SO4^2-/TiO2-SiO2替代传统的液体酸、碱催化剂,催化较高酸值麻疯树籽油与甲醇进行酯交换反应制备生物柴油。考察了搅拌速度、固体酸催化剂用量、醇油摩尔比、反应温度、助溶剂等因素对产物中甲酯含量的影响。结果表明,固体酸催化剂对麻疯树籽油酯交换具有较好的催化活性和稳定性,产物与催化剂易于分离。在反应温度110℃,醇油摩尔比12:1,固体酸催化剂用量为油质量的4%。搅拌速度600r/min,助溶剂正己烷与甲醇体积比1:2条件下,反应3h产物中麻疯树籽油甲酯含量达到96.8%。反应10次甲酯含量维持在95%。  相似文献   

11.
Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.  相似文献   

12.
Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.  相似文献   

13.
An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.  相似文献   

14.
<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of  相似文献   

15.
《印刷工业》2014,(9):94-95
In the 2014 China(Shanghai)International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;  相似文献   

16.
正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly  相似文献   

17.
正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,  相似文献   

18.
《造纸信息》2014,(8):99-100
On December 24th, 2013, the meeting on the selection of top 10 news of China's paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.  相似文献   

19.
《造纸信息》2014,(8):83-84
In Apri Commi major p Plan" (h 2014, the National Development and Reform ssion issued an announcement for selection of reliminary research projects for the "13th Five-Year ereafter referred to as "The Announcement")  相似文献   

20.
<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the latest scientific  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号