双酸位分子筛的制备及催化合成单癸酸甘油酯北大核心CSCD

为了制备适用于催化合成单癸酸甘油酯(GMC)的催化活性高、重复利用性强以及热稳定性好的固体酸催化剂,以钛酸四丁酯为钛源、正硅酸乙酯为硅源,采用软模板法在酸性条件下合成Ti-SBA-15,再通过有机接枝的方法引入磺酸基团,制备了同时含有Bronsted酸位点和Lewis酸位点的介孔分子筛催化剂Ti-SBA-15-SO3H。采用XRD、FT-IR、Py-IR、BET、EDS等表征手段对该催化剂的表面结构、化学键、酸性位点及酸量、孔道结构、元素分布进行评价,对总酸量进行了测定。以甘油与癸酸酯化合成GMC反应作为探针反应,考察了介孔分子筛催化剂的催化活性。结果表明,Ti的掺入为介孔分子筛提供了Lewis酸位点,引入的磺酸基团增加了介孔分子筛的Bronsted酸位点,同时所制得的Ti-SBA-15-SO3H保留了SBA-15原有表面和孔道结构。该催化剂在反应时间5 h、反应温度150℃、甘油与癸酸物质的量比4∶1、催化剂用量4%(以总反应物质量计)的条件下,癸酸转化率接近98%,GMC收率达78%以上。该催化剂在循环使用4次之后,GMC收率仍高于70%。制备得到的双酸位分子筛催化剂催化活性高、重复利用性强、热稳定性好,适用于催化合成GMC。     

改性多级孔分子筛的合成及其对酸性橙Ⅱ的吸附性能

为增强分子筛的吸附性能,采用离子交换法对微孔分子筛13X进行改性,再通过水热晶化法制备成型的改性多级孔分子筛。利用XRD和N_2吸附-脱附等方法表征了改性分子筛的结构,并评价了其对酸性橙Ⅱ的吸附性能。结果表明:改性多级孔分子筛兼具微孔和介孔分子筛的特点,比表面积为893.7 m~2/g,总孔容为0.87 cm~3/g,平均孔径为3.15 nm;在pH=3、温度25℃、酸性橙Ⅱ初始质量浓度20 mg/L的条件下,0.20 g/L改性多级孔分子筛吸附70 min后对酸性橙Ⅱ的去除率可达97.05%。此吸附过程属于单分子层吸附,可通过Langmuir等温吸附模型进行描述。     

MCM-41分子筛催化D-葡萄糖酸制备D-葡萄糖酸-δ-内酯的研究

以MCM-41分子筛为催化剂,由D-葡萄糖酸制备D-葡萄糖酸-δ-内酯.考察了反应温度、反应时间、催化剂用量以及催化剂循环使用次数对D-葡萄糖酸-δ-内酯产率的影响.实验结果表明,MCM-41是制备D-葡萄糖酸-δ-内酯较好的催化剂.最佳工艺条件为:催化剂用量为30%,反应温度80℃,反应时间2h,D-葡萄糖酸-δ-内...     

PEG-1000对多级孔ZSM-5分子筛合成及吸附性能的影响

以饱和ATP吸附材料为硅源,用四丙基溴化铵(TPABr)为微孔模板剂和聚乙二醇1000(PEG-1000)为介孔模板剂合成多级孔ZSM-5分子筛.通过X射线衍射分析(XRD)、傅里叶红外分析(FT-IR)、扫描电子显微镜(SEM)和比表面积及孔径分析仪等表征合成产物的形貌、结构及孔道特征;再利用亚甲基蓝溶液测试其吸附性能.结果表明PEG-1000投加量对合成产物的晶型影响不明显,皆为多级孔ZSM-5分子筛,均具有较大的比表面积(约300m~2/g).随着PEG-1000投加量提高,分子筛晶体逐渐粗糙并呈近球状,介孔量和平均孔径均有所增加;当PEG-1000投加量为0.30g时,比表面积为274.230 2m~2/g,介孔所占比例47.92%,平均孔径2.68nm.在亚甲蓝溶液质量浓度为10mg/L,pH为11,吸附150min时,所合成ZSM-5分子筛对亚甲基蓝吸附率达98.2%.     

多级孔ZSM-5分子筛催化餐厨废油制备轻质芳烃的研究

采用水热法合成不同硅铝摩尔比的多级孔ZSM-5分子筛,并对其结构进行表征,考察不同硅铝摩尔比多级孔ZSM-5分子筛对餐厨废油模型化合物(WCOMC)制备苯、甲苯和二甲苯(3种物质统称BTX)的影响。结果表明：L-赖氨酸的加入提高了多级孔ZSM-5分子筛的传质效率,其硅铝摩尔比的变化有效地调节了多级孔ZSM-5分子筛的酸性,且多级孔ZSM-5分子筛的酸性影响目标产物的分布和反应体系的稳定性。随着温度的升高,芳烃的相对含量提高,在600℃条件下多级孔ZSM-5-40分子筛催化WCOMC制备BTX的相对含量最高,为20.3%。     

中空介孔二氧化硅负载磷钨酸催化剂的制备及其在生物柴油合成中的应用

以正硅酸乙酯为硅源,使用改进后的Stber法合成实心二氧化硅球（SiO2）,然后用Na2CO3和十六烷基三甲基溴化铵(C16TAB）对其进行选择性地一步刻蚀,得到中空介孔二氧化硅纳米球（HMSN）,最后使用改进后的浸渍法引入磷钨酸作为活性中心,由此得到中空介孔二氧化硅负载磷钨酸的纳米催化剂（HPW/HMSN）。用FTIR、XPS、XRD、BET、SEM、TEM、EDS、TGA等对制备的催化剂进行表征,并用间接滴定法测定其酸量。结果证明,磷钨酸被成功引入载体表面,所合成的催化剂具有中空介孔结构,并且粒径均一、单分散性好,催化剂比表面积高达481 m2/g。酸量（H+）高达340.4 μmol/g。通过单因素试验确定催化剂对油酸和甲醇合成生物柴油的最佳反应条件为反应温度80 ℃、反应时间2 h、醇油摩尔比10∶ 1和催化剂用量为原料总质量的3%,在此条件下油酸转化率可达98.7%。此外,催化剂具有良好的可重复使用性,在重复使用5次时仍保持了852%的油酸转化率。     

13X/SBA-15复合分子筛的制备及其处理造纸废水的研究

本研究首先对13X分子筛(微孔)和SBA-15分子筛(介孔)进行改性,然后通过后合成法将两种改性分子筛合成为一种复合分子筛,对复合分子筛进行结构表征,并分析了复合分子筛对造纸中段废水的处理效果。结果表明,合成的复合分子筛兼具微孔和介孔结构,比表面积为620. 2 m~2/g,总孔容为1. 15 cm~3/g,平均孔径为6. 18 nm;废水处理结果表明,在温度40℃、复合分子筛用量为1. 0 g/L、pH值为7. 8,吸附时间60 min的条件下,复合分子筛对造纸中段废水中色度、固体悬浮物(SS)和CODCr的去除率分别可达98. 8%、85. 7%和81. 4%。该复合分子筛具有良好的再生吸附性能,可以多次循环使用。     

Ru/MCM-41催化葡萄糖加氢制备山梨醇的研究

以MCM-41分子筛为载体,采用甲醛还原法制备Ru/MCM-41催化剂,将其用于葡萄糖氢化制备山梨醇。考察了反应温度、反应时间以及Ru/MCM-41催化剂循环使用次数对山梨醇产率和选择性的影响。实验结果表明：在葡萄糖浓度为10%、催化剂用量为20%（以葡萄糖用量计）,反应温度为120℃时,反应1.5h后,葡萄糖转化率达到100%,而山梨醇产率可达94.43%。同时,催化剂循环使用研究表明,Ru/MCM-41是一种较理想的催化剂,可循环使用3～4次。     

疏水固体酸催化大豆酸化油酯化生产生物柴油研究

以疏水性介孔分子筛SBA-15-SO3H固体酸为催化剂,以大豆酸化油和甲醇为原料,通过酯化反应生产生物柴油。通过TGA、X射线粉末衍射（XRD）、相对润湿接触角等方法对样品进行了表征。结果表明：酯化反应的最佳反应条件是,反应温度100℃,催化剂用量5%,甲醇流量15g/h,反应时间4h,酯化率达到99.5%。疏水固体酸C16H33-SBA-15-SO3H作为大豆酸化油酯化生产生物柴油的良好催化剂,有良好的工业应用前景。     

响应面法优化磷钨酸介孔分子筛催化制备大豆油基多元醇

采用响应面法对磷钨酸介孔分子筛催化环氧大豆油制备大豆油基多元醇进行了优化研究。结果表明:以甲醇作为开环反应试剂,磷钨酸介孔分子筛可较好地催化环氧大豆油开环制备大豆油基多元醇;通过Box-Behnken设计,利用Design-expert 8.0软件进行二次回归分析,确定大豆油基多元醇最佳制备条件为反应时间3 h、磷钨酸介孔分子筛用量为环氧大豆油质量的3%、甲醇与环氧大豆油摩尔比13∶1、反应温度75℃,在此条件下大豆油基多元醇的转化率为77.25%。     

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.     

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.     

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.     

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.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.