双核酸性离子液体[DABCO-PS][HSO_4]催化蓖麻油制备生物柴油研究

研究合成了双核酸性离子液体[DABCO-PS][HSO_4],并将其用于催化蓖麻油酯交换制备生物柴油。优化后得离子液体前体[DABCO-PS]合成最佳条件为n(1,3-丙烷磺酸内酯)∶n(三乙烯二胺)=2∶1、反应温度60℃、反应时间3 h,在此条件下离子液体前体收率达93.4%。采用红外光谱、核磁共振和质谱对[DABCO-PS][HSO_4]进行表征,确定产物为目标离子液体。优化得到[DABCO-PS][HSO_4]催化蓖麻油制备生物柴油的最佳条件为n(甲醇)∶n(蓖麻油)=12∶1、离子液体用量4%(以蓖麻油质量计)、反应温度50℃、反应时间1 h,在此条件下生物柴油收率达90%。采用气相色谱确定生物柴油主要成分是棕榈酸甲酯、亚油酸甲酯、油酸甲酯、亚麻酸甲酯、硬脂酸甲酯和蓖麻油酸甲酯,且脂肪酸甲酯占生物柴油的90%以上。     

酸性离子液体催化月桂酸制备生物柴油工艺的研究

以新型酸性离子液体1-丁基喹啉硫酸氢盐（[BQu]HSO4）为催化剂催化月桂酸与甲醇酯化反应制备生物柴油工艺研究,详细考察了离子液体用量、醇酸摩尔比、反应时间及反应温度等因素对月桂酸甲酯产率的影响。在单因素实验基础上利用响应面分析法优化月桂酸甲酯的最佳制备工艺条件为：离子液体用量为月桂酸质量的1.3%,甲醇与月桂酸摩尔比为2.8:1,反应时间3.2 h,反应温度373 K,此条件下生物柴油产率为96.3%,该结果与模型预测值基本相符。最佳条件下,制备月桂酸甲酯反应的活化能为25.25 kJ/mol,动力学方程为： 。     

响应曲面法尼泊金甲酯合成工艺改进

文章以对羟基苯甲酸和甲醇在离子液体[Hmim]+BF4-催化下反应得到尼泊金甲酯。通过响应曲面法优化了反应的条件,得到尼泊金甲酯合成的最佳工艺:醇与酸的摩尔比为3.25,离子液体投加量为1.4mL(以对羟基苯甲酸为0.1mol为准),反应时间为4h,反应温度为45℃,在此最佳条件下,产率可达90.64%。     

硅胶固载磺酸功能化离子液体催化棕榈酸制备生物柴油的工艺研究

以硅胶固载N,N-二甲基苄胺丙基磺酸基硫酸氢盐离子液体([DMBPSH]HSO_4/SG)为催化剂,进行棕榈酸与甲醇酯化制备生物柴油工艺研究,考察了醇酸摩尔比、催化剂用量、反应时间及反应温度等因素对棕榈酸甲酯收率的影响。研究表明,10%[DMBPSH]HSO_4/SG催化剂具有最好的催化酯化活性;以10%[DMBPSH]HSO_4/SG为催化剂,利用响应面分析法优化生物柴油的最佳制备工艺条件为:醇酸摩尔比12.6∶1,催化剂用量为棕榈酸质量的5.3%,反应时间2.3 h,温度368 K,此条件下,棕榈酸甲酯的收率为97.2%,该结果与模型预测值基本相符。最佳条件下,棕榈酸甲酯合成反应的活化能为15.89 kJ/mol,动力学方程为:■。     

一步法制备纤维素氯乙酸酯及其原子转移自由基接枝共聚

以离子液体为反应介质,氯乙酰氯为酰化试剂,在不加任何催化剂的条件下,一步法制备出纤维素氯乙酰酸酯.研究了反应条件(酰化试剂用量、反应时间、反应温度)对纤维素取代度(DS)的影响,并对产物结构进行表征(FT-IR、NMR).随后以纤维素氯乙酰酸酯为大分子引发剂,引发了甲基丙烯酸甲酯(MMA)在离子液体中的原子转移自由基聚合(ATRP).研究结果表明,MMA在离子液体中的聚合是活性/可控的.     

蓖麻油生物柴油的减压蒸馏及气-质谱分析

分别以浓硫酸和氢氧化钠为催化剂,以蓖麻油和甲醇为原料制备了生物柴油样品,并对其进行了减压蒸馏.用气-质联用仪对蒸馏样品进行了分析.结果表明:由蓖麻油制得的生物柴油主要成分为蓖麻酸甲酯,还含有少量油酸甲酯、亚油酸甲酯、十六酸甲酯及十八酸甲酯等成分;当减压蒸馏的液相温度较高、升温速率较慢时,少部分蓖麻酸甲酯将分解为10-十一烯酸甲酯和庚醛;当减压蒸馏的生物柴油样品含硫酸催化剂时,大部分蓖麻酸甲酯将发生脱水反应生成亚油酸甲酯.     

硫酸化脂肪酸甲酯加脂剂制备工艺的研究

以脂肪酸甲酯为原料、离子液体为催化剂,以碘值为指标考察硫酸化脂肪酸甲酯反应条件.在单因素实验基础上,通过正交实验确定了硫酸化脂肪酸甲酯合成的最佳工艺条件:离子液体用量1.0％(以甲酯质量为基准),浓硫酸用量30％,反应温度25℃,反应时间3h.在最佳工艺条件下,硫酸化脂肪酸甲酯的碘值(Ⅰ)可达最低,为42.45 g/100 g.通过红外分析,证明了目标产物的生成.     

氢化棕榈酸甲酯磺酸盐的制备

在氯仿体系中,以氢化棕榈酸甲酯为原料、氯磺酸为磺化剂,通过磺化、老化、中和、干燥后制得氢化棕榈酸甲酯磺酸盐.经单因素及正交实验优化得到最佳工艺条件:滴加温度40℃,氯仿与甲酯质量比2.0∶1.0,氯磺酸与甲酯物质的量比1.55∶1.0,磺化时间60 min,老化时间70 min.在最佳工艺条件下,制备的产品颜色呈淡黄色,氢化棕榈酸甲酯磺酸盐的含量为64.36％.     

新型酸性离子液体[Hmim]HSO_4催化合成油酸甲酯

以N-甲基咪唑和浓硫酸为原料,制备了一种新型Brφnsted酸性离子液体[Hmim]HSO4,并将其应用到油酸甲酯的合成中。采用红外光谱法分析[Hmim]HSO4的化学结构,然后采用气质联用法对所得油酸甲酯进行定性分析。结果表明,酸性离子液体[Hmim]HSO4催化合成油酸甲酯的优化条件为:酸醇摩尔比1∶4(0.04 mol油酸)、离子液体用量3.5 m L、反应时间6 h,在此条件下,油酸酯化率为92.5%。酸性离子液体[Hmim]HSO4具有较好的催化活性,重复使用9次后,油酸酯化率仍在85%以上,且易与产品分离,克服了传统无机酸催化的缺陷。     

响应面法优化L-谷氨酸离子液体催化制备油酸甲酯北大核心CSCD

为了开发环境友好型高效催化剂催化油酸酯化制备生物柴油,以L-谷氨酸与不同无机酸(硫酸、硝酸和磷酸)为原料合成了3种离子液体,对这3种离子液体催化油酸酯化反应制备油酸甲酯的酯化率进行了考察,筛选出催化效率较优的一种离子液体,对其进行傅里叶红外光谱表征,并进一步采用响应面法对其催化油酸酯化反应的工艺参数进行优化。结果表明:在3种离子液体中[L-Glu]HSO_(4)的催化效率最高;[L-Glu]HSO_(4)催化油酸酯化的最佳反应条件为离子液体用量15%、醇酸摩尔比11∶1、反应温度70℃、反应时间12 h,在此条件下酯化率为97.02%。因此,所合成的[L-Glu]HSO_(4)可以高效催化油酸酯化制备生物柴油。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

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.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<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