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41.
硬脂酸脂肪酯作为温室控温相变材料的制备及性能研究 总被引:1,自引:0,他引:1
相变材料可对室内温度进行调控,采用酰氯醇解法将硬脂酸及直链脂肪醇合成系列硬脂酸酯(18-8,18-10,18-12,18-14)作为温室控温相变材料,并通过傅里叶变换红外光谱(FT—IR)、核磁共振(1H NMR)、差示扫描量热仪(DSC)、热重分析仪(TGA)、导热仪等对其结构、热性能及导热性能等进行了测定。结果表明:该系列硬脂酸酯的相变温度为22.2~44.8oC,相变焓为138.7~155.7 kJ·kg~(-1),并具有良好的热稳定性和导热性能,适于作为温室控温相变材料。 相似文献
42.
Mustafa E. Tat Paul S. Wang Jon H. Van Gerpen Thomas E. Clemente 《Journal of the American Oil Chemists' Society》2007,84(9):865-869
Biodiesel is a fuel comprising mono-alkyl esters of medium to long-chain fatty acids derived from vegetable oils or animal
fats. Typically, engines operated on soybean-based biodiesel exhibit higher emissions of oxides of nitrogen (NOx) compared
with petroleum diesel. The increase in NOx emissions might be an inherent characteristic of soybean oil’s polyunsaturation,
because the level of saturation is known to affect the biodiesel’s cetane number, which can affect NOx. A feedstock that is
mostly monounsaturated (i.e. oleate) helps to balance the tradeoff between cold flow and oxidative stability. Genetic modification
has produced a soybean event, designated 335-13, with a fatty acid profile high in oleic acid (>85%) and with reduced palmitic
acid (<4%). This high-oleic soybean oil was converted to biodiesel and run in a John Deere 4045T 4.5-L four-stroke, four-cylinder,
turbocharged direct-injection diesel engine. The exhaust emissions were compared with those from conventional soybean oil
biodiesel and commercial No. 2 diesel fuel. There was a significant reduction in NOx emissions (α = 0.05) using the high-oleic soybean biodiesel compared with regular soybean oil biodiesel. No significant differences were
found between the regular and high-oleic biodiesel for unburned hydrocarbon and smoke emissions. 相似文献
43.
Sulaiman Al-Khattaf Syed A. Ali Abdullah M. Aitani Naděžda Žilková David Kubička 《Catalysis Reviews》2014,56(4):333-402
Alkylbenzenes form an important segment of petrochemical industry for the manufacture of widely used commodities and specialty products. Since the last review on this topic (8), numerous new zeolite-based catalysts have been synthesized, characterized and evaluated in various transformations of aromatic hydrocarbons. This comprehensive review covers major reactions of mono-, di-, and tri-alkylbenzenes such as disproportionation, alkylation, transalkylation, isomerization, etc., over different zeolite-based acid catalysts. During the last decade, significant progress was made in the synthesis and structure determination of novel zeolites, mesoporous single crystals, hierarchic zeolites and two-dimensional zeolites. These developments have enhanced the understanding of the role of zeolites (effects of structural type, morphology, acid sites, accessibility of acid sites, shape selectivity factors) in transformations of aromatics. In this review, the emphasis is on the influence of the type of acid sites, zeolite topology, and reaction conditions on the activity, selectivity and pathways of these reactions. Thermodynamics and reaction kinetics of transformations of aromatic hydrocarbons are also discussed. This article covers mostly literature published during the period of 2002–2013. 相似文献
44.
Synthesis,Corrosion Inhibition Performance and Biodegradability of Novel Alkyl Hydroxyethyl Imidazoline Salts 下载免费PDF全文
Hongqin Liu Jun Hu Xiaoze Zhou Dan Liu Baocai Xu Yawen Zhou 《Journal of surfactants and detergents》2015,18(6):1025-1031
New alkyl hydroxyethyl imidazoline salts were synthesized via a high pressure process with imidazoline and dimethyl carbonate, and their chemical structure were confirmed using mass spectral fragmentation and FTIR spectroscopic analysis. In addition, several quaternary ammonium salts with new counterions (formic acid, acetic acid and lactic acid) were also synthesized by ion exchange reaction of methyl carbonate quaternary ammoniums with the corresponding acids. These new compounds reduced the surface tension of water to a minimum value of approximately 27 mN m?1 at a concentration of 8.72 × 10?5 mol L?1. They also show efficient corrosion inhibition performances and could significantly inhibit the corrosion of mild steel in acid solutions. It was also found that the biological degradation of these imidazoline surfactants was greater than 98 % after 7 days. 相似文献
45.
Hee-Kyoung Kang Chang Ho Seo Yoonkyung Park 《International journal of molecular sciences》2015,16(3):6018-6056
Marine organisms have been recognized as a valuable source of bioactive compounds with industrial and nutraceutical potential. Recently, marine-derived carbohydrates, including polysaccharides and low molecular weight glycosylated oligosaccharides, have attracted much attention because of their numerous health benefits. Moreover, several studies have reported that marine carbohydrates exhibit various biological activities, including antioxidant, anti-infection, anticoagulant, anti-inflammatory, and anti-diabetic effects. The present review discusses the potential industrial applications of bioactive marine carbohydrates for health maintenance and disease prevention. Furthermore, the use of marine carbohydrates in food, cosmetics, agriculture, and environmental protection is discussed. 相似文献
46.
以甘薯淀粉烷基糖苷(APG)为原料,合成了阴离子表面活性剂淀粉烷基糖苷磺基琥珀酸酯钠盐(APGSS)。研究了影响APG与马来酸酐(MA)的酯化反应及酯与NaHSO3磺化反应的各种因素,得出比较适宜的催化剂及反应条件:酯化反应以对甲苯磺酸作催化剂,其用量为APG与马来酸酐总质量的1.5%,反应温度100℃,n(APG)∶n(MA)=1∶1,反应时间4h;磺化反应温度120℃,n(NaHSO3)∶n(酯)=1∶1,反应时间2.5 h。通过红外光谱分析确定了产物结构,并测定了产物的物理化学性能,结果表明:产物APGSS临界胶束浓度为0.2 mg/L,其泡沫性能和润湿性能比APG均有提高。 相似文献
47.
48.
Marc De Doncker Chloé De Graeve Dr. Jorick Franceus Dr. Koen Beerens Prof. Vladimír Křen Dr. Helena Pelantová Dr. Ronny Vercauteren Prof. Dr. Tom Desmet 《Chembiochem : a European journal of chemical biology》2021,22(23):3319-3325
The substantial increase in DNA sequencing efforts has led to a rapid expansion of available sequences in glycoside hydrolase families. The ever-increasing sequence space presents considerable opportunities for the search for enzymes with novel functionalities. In this work, the sequence-function space of glycoside hydrolase family 94 (GH94) was explored in detail, using a combined approach of phylogenetic analysis and sequence similarity networks. The identification and experimental screening of unknown clusters led to the discovery of an enzyme from the soil bacterium Paenibacillus polymyxa that acts as a 4-O-β-d -glucosyl-d -galactose phosphorylase (GGalP), a specificity that has not been reported to date. Detailed characterization of GGalP revealed that its kinetic parameters were consistent with those of other known phosphorylases. Furthermore, the enzyme could be used for production of the rare disaccharides 4-O-β-d -glucosyl-d -galactose and 4-O-β-d -glucosyl-l -arabinose. Our current work highlights the power of rational sequence space exploration in the search for novel enzyme specificities, as well as the potential of phosphorylases for rare disaccharide synthesis. 相似文献
49.
Nicola Curci Andrea Strazzulli Roberta Iacono Federica De Lise Luisa Maurelli Mauro Di Fenza Beatrice Cobucci-Ponzano Marco Moracci 《International journal of molecular sciences》2021,22(7)
In the field of biocatalysis and the development of a bio-based economy, hemicellulases have attracted great interest for various applications in industrial processes. However, the study of the catalytic activity of the lignocellulose-degrading enzymes needs to be improved to achieve the efficient hydrolysis of plant biomasses. In this framework, hemicellulases from hyperthermophilic archaea show interesting features as biocatalysts and provide many advantages in industrial applications thanks to their stability in the harsh conditions encountered during the pretreatment process. However, the hemicellulases from archaea are less studied compared to their bacterial counterpart, and the activity of most of them has been barely tested on natural substrates. Here, we investigated the hydrolysis of xyloglucan oligosaccharides from two different plants by using, both synergistically and individually, three glycoside hydrolases from Saccharolobus solfataricus: a GH1 β-gluco-/β-galactosidase, a α-fucosidase belonging to GH29, and a α-xylosidase from GH31. The results showed that the three enzymes were able to release monosaccharides from xyloglucan oligosaccharides after incubation at 65 °C. The concerted actions of β-gluco-/β-galactosidase and the α-xylosidase on both xyloglucan oligosaccharides have been observed, while the α-fucosidase was capable of releasing all α-linked fucose units from xyloglucan from apple pomace, representing the first GH29 enzyme belonging to subfamily A that is active on xyloglucan. 相似文献
50.
A facile strategy for the introduction of tert-butyl and hexyl chains to the indolo[3,2,1-jk]carbazole scaffold is presented. With these building blocks six materials based on three different 4,4′-bis(N-carbazolyl)-1,1-biphenyl derivatives with varying degree of planarization were prepared. Characterization of the materials showed that the alkyl chains have only minor effects on the photophysical properties of the compounds. In contrast, thermal robustness towards decomposition and electrochemical stability are increased by the introduced alkyl chains. Detailed investigation of the solubility in five different solvents revealed that the incorporation of the alkyl chains increases the solubility significantly. The increased solubility of the materials allowed the application as host materials in red, green and sky-blue solution processed phosphorescent organic light emitting diodes. Hence, this work presents the first solution processed light emitting devices based on the indolo[3,2,1-jk]carbazole scaffold. 相似文献