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1.
着重介绍了来源于植物组织中的两种活性不同的糖苷,即甜糖苷和抑甜糖苷的特性以及研究现状。  相似文献   

2.
以一水葡萄糖、月桂醇为原料 ,对甲苯磺酸为催化剂 ,经直接苷化法合成了月桂基葡糖苷 ,对产品结构进行了表征 ,计算了烷基多苷的平均聚合度、α 吡喃糖苷和 β 吡喃糖苷的比例。考察了反应条件对平均聚合度、α 和 β 吡喃糖苷比例及吡喃糖苷与呋喃糖苷比例的影响。结果表明 :通过改变醇糖摩尔比、反应温度、催化剂用量、反应时间等条件可有效控制平均聚合度、α 和 β 吡喃糖苷比例及呋喃糖苷的生成  相似文献   

3.
马新涛  宋春玲 《应用化工》2007,36(2):207-209
以对甲苯磺酸为催化剂,以葡萄糖和脂肪醇作原料,采用转糖苷化法合成了烷基葡糖苷,考察了工艺条件对合成烷基糖苷的影响。结果表明,催化剂∶葡萄糖=0.011∶1(质量比),葡萄糖∶正丁醇=1∶3(摩尔比),正丁醇∶脂肪醇=1∶1(摩尔比),常压反应,反应温度为110~115℃,葡萄糖转化率可达98.9%。  相似文献   

4.
本文采用无水葡萄糖、乙二醇和十二烷醇为原料,经两步转糖苷法制备烷基糖苷。采用正交法设计实验,以烷基糖苷产率为考察指标,考察了反应温度、反应时间、醇糖比以及催化剂用量对合成烷基糖苷产率的影响,计算出十二烷基糖苷产品的产率与各因素间的关系,得到最佳实验条件:葡萄糖与乙二醇用量比为1:7,葡萄糖与十二醇用量比为1:8,催化剂用量为葡萄糖量的2.6%,反应温度为120℃,反应时间为4.5 h。  相似文献   

5.
介绍了十余年来烷基糖苷(APG)及其衍生物的国内外技术进展。直接催化缩醛化制备APG的清洁工艺在国内成熟于"九五"末期,并相继突破了合成反应控制技术、高效脱醇技术、产品漂色处理技术以及规模化生产技术。烷基糖苷衍生物可以拓展APG的功能性和应用领域,近期出现了糖苷阳离子、糖苷阴离子和功能性糖苷非离子衍生物等众多品种类型,其中部分品种已经产业化并作为特种功能助剂得到广泛应用。可以预见,基于可再生天然资源的糖苷类绿色、多功能性表面活性剂将得到更多的关注。  相似文献   

6.
烷基糖苷的制备   总被引:4,自引:0,他引:4  
介绍了烷基糖苷的性能及发展状况,阐述了糖苷化反应机理,同时对烷基糖苷的两种合成方法进行了概述。指出,烷基糖苷是一种无毒、无刺激和相容性好、完全能生物降解、及对环境无害的非离子表面活性剂。  相似文献   

7.
吴婷婷  石浩 《浙江化工》2012,43(5):16-21
甜菊糖苷是一种天然甜味刑,在酸性条件下水解为异甜菊醇。异甜菊醇具有降血压、降血糖、抗炎和抗肿瘤等生理活性。本文对异甜菊醇及其衍生物在抗炎、抗肿瘤、手性催化和分子识别方面的应用研究进行了总结。  相似文献   

8.
刘艳蕊  王春利 《辽宁化工》2014,(9):1119-1121
利用转糖苷化法合成烷基糖苷,对合成烷基糖苷的催化剂体系做了一定改进,并对催化剂的用量做了研究,确定了合成烷基糖苷的最优催化剂体系。  相似文献   

9.
本文对烷基糖苷的合成、性质及应用作了系统的综述,反映了烷基糖苷的最新研究成果和研究方向。  相似文献   

10.
烷基糖苷的合成技术进展   总被引:2,自引:0,他引:2  
介绍了近年来烷基糖苷的合成方法,反应机理和影响反应的因素。  相似文献   

11.
Cycloaliphatic C21 di- and C22 tricarboxylic acids were prepared by the Diels-Alder reaction of dehydrated castor oil (DCO) fatty acids (containing 48% conjugated and 42% nonconjugated dienes) with acrylic and fumaric acids, respectively. The reaction temperature, time, catalyst concentration, and mole ratio of reactants were varied to get maximum yields of the di- and tricarboxylic acids. The unreacted DCO fatty acids were removed from the products by partition between aqueous methanol and n-hexane. The products were converted to methyl esters and characterized as the substituted cyclohexene derivatives before and after dehydrogenation with Pd/C in xylene, hydrogenation with Pd/C in decalin and oxidation with periodate-permanganate reagent and by mass and proton nuclear magnetic resonance spectrometry. The acids were converted to sodium soaps, mono- and diethanolamides and the corresponding diol and triol sulfates, and the resulting products were evaluated for their surface-active properties. The sodium soaps showed better calcium tolerance and poorer foaming power than sodium oleate. The diethanolamides were inferior to lauroyl diethanolamide in wetting and emulsifying power. The monoethanolamides were better than the respective diethanolamides and lauroyl diethanolamide in wetting property. The diol and triol sulfates were poorer in wetting and emulsifying ability and better in calcium tolerance than sodium lauryl sulfate.  相似文献   

12.
民用工业中复合材料桁架的应用和发展   总被引:1,自引:0,他引:1  
本文叙述了复合材料桁架的构造、分类和计算方法,突出了复合材料桁架的优越性能和在民用工业中的应用前景;在分析大量文献资料的基础上阐述复合材料桁架杆件的多种加工工艺,并比较不同截面形式对杆件性能的影响;探讨复合材料杆件的破坏机理和分析方法,介绍节点的类型和各自的特点,提出节点及连接部位存在的关键问题;根据国内外复合材料桁架的研究和应用现状,阐述了复合材料桁架的性能和不同的设计方法,总结归纳影响复合材料桁架性能的关键因素和设计中存在的一些问题,并提出改进杆件设计、节点设计和优化复合材料桁架的建议。  相似文献   

13.
熟料的岩相分析有助于熟料质量的判断及生产过程控制调整。根据多年实践经验,总结了手工和机械磨制岩相试样的方法及注意事项,并对几种熟料岩相特征(孔洞、游离氧化钙、A矿包裹B矿和f-Ca O、晶体尺寸不均和矿巢)进行了举例和形成原因分析。  相似文献   

14.
The effects of extraction temperature and preservation method on the functional properties of soy protein isolate (SPI) were determined. Four extraction temperatures (25, 40, 60, and 80 °C) were used to produce SPI and yields of solids and protein contents were determined. Three preservation methods were also tested (spray-drying, freeze-drying, and freezing–thawing) and compared to fresh (undried) samples for each extraction temperature. No differences in yields of solids and protein were observed among SPIs extracted at 25, 40, and 60 °C; however, SPI extracted at 80 °C yielded significantly less solids and protein. Extraction temperature significantly affected SPI functionality. As extraction temperature increased, solubility and emulsification capacity decreased; surface hydrophobicities, emulsification activities and stabilities, and dynamic viscosities increased; and foaming properties improved. Preservation method also significantly affected SPI functionality. Drying method did not affect the denaturation enthalpies of SPIs, but spray-dried SPIs had higher solubilities, surface hydrophobicities, and emulsification stabilities, and lower viscosities, emulsification activities and rates of foaming than freeze-dried SPI exhibited. Emulsification and foaming capacities and foaming stabilities were similar for both methods of drying. There was significant interaction between extraction temperature and preservation method for all functional properties except emulsification capacity.  相似文献   

15.
The scientific community and industrial companies have discovered significant enzyme applications to plant material. This rise imparts to changing consumers’ demands while searching for ‘clean label’ food products, boosting the immune system, uprising resistance to bacterial and fungal diseases, and climate change challenges. First, enzymes were used for enhancing production yield with mild and not hazardous applications. However, enzyme specificity, activity, plant origin and characteristics, ratio, and extraction conditions differ depending on the goal. As a result, researchers have gained interest in enzymes’ ability to cleave specific bonds of macroelements and release bioactive compounds by enhancing value and creating novel derivatives in plant extracts. The extract is enriched with reducing sugars, phenolic content, and peptides by disrupting lignocellulose and releasing compounds from the cell wall and cytosolic. Nonetheless, depolymerizing carbohydrates and using specific enzymes form and release various saccharides lengths. The latest studies show that oligosaccharides released and formed by enzymes have a high potential to be slowly digestible starches (SDS) and possibly be labeled as prebiotics. Additionally, they excel in new technological, organoleptic, and physicochemical properties. Released novel derivatives and phenolic compounds have a significant role in human and animal health and gut-microbiota interactions, affecting many metabolic pathways. The latest studies have contributed to enzyme-modified extracts and products used for functional, fermented products development and sustainable processes: in particular, nanocellulose, nanocrystals, nanoparticles green synthesis with drug delivery, wound healing, and antimicrobial properties. Even so, enzymes’ incorporation into processes has limitations and is regulated by national and international levels.  相似文献   

16.
We report self-assembly and phase transition behavior of lower diamondoid molecules and their primary derivatives using molecular dynamics (MD) simulation and density functional theory (DFT) calculations. Two lower diamondoids (adamantane and diamantane), three adamantane derivatives (amantadine, memantine and rimantadine) and two artificial molecules (ADM•Na and DIM•Na) are studied separately in 125-molecule simulation systems. We performed DFT calculations to optimize their molecular geometries and obtained atomic electronic charges for the corresponding MD simulation, by which we predicted self-assembly structures and simulation trajectories for the seven different diamondoids and derivatives. Our radial distribution function and structure factor studies showed clear phase transitions and self-assemblies for the seven diamondoids and derivatives.  相似文献   

17.
The current year's growth of Douglas fir contains galactose, unusual in that this carbohydrate makes up 78.7% of the total carbohydrate fraction. An agar diet study was undertaken to determine the effects of galactose, other carbohydrates, and terpenes on western spruce budworm larval mortality, growth rate, and adult biomas production. All concentrations of the carbohydrates and terpenes tested, as well as other mineral elements not tested, were typical of the current year's foliage of Douglas fir. In experiment I, the diet containing 5.61% total carbohydrate did not significantly affect larval mortality when compared to the control diet. However, diets containing 9.45% and 15% total carbohydrate concentrations significantly increased larval mortality 64% and 96.1%, respectively, when compared to the control. Also in experiment I, terpenes alone (78.9% morality) and terpenes in combination with 9.45% and 15% total carbohydrates significantly increased larval mortality (97.2% and 100%, respectively) when compared to mortality on the control diet (44%). To determine which carbohydrate was causing the adverse effect, 6% glucose, 6% fructose, and 6% galactose were placed individually and in combination with terpenes in diets in experiment II. The 6% galactose diet significantly increased larval mortality and reduced growth rate when compared to the control, glucose, and fructose diets. Glucose resulted in 16% less larval mortality, significantly enhanced female larval growth rate and pupal weight, but did not affect male larval growth rate and pupal weight, when compared to the control. Fructose resulted in a significant decrease in larval mortality and a general trend of enhanced female and male larval growth rate and pupal weight. Larval mortality on terpenes alone was not significantly different from the control, but terpenes with 6% galactose increased larval mortality and decreased female and male growth rate and pupal weight significantly when compared to glucose-terpene and fructose-terpene diets. No significant interactions were found between carbohydrates and terpenes in either experiment.  相似文献   

18.
There is an increased demand for convenient foods including ready-to-eat and instant products. These products are desired with minimum concentration of synthetic chemicals. This creates challenges for the food industry and dryers manufactures to develop new technologies to process difficult-sensitive materials and to supply final products with high quality and improved properties. Fruits and vegetables are mainly composed of water, carbohydrates, proteins and lipids. Due to modification of chemical and physical bonds the compounds the material becomes viscous and sticky during processing. Conventional dryers have limitations in handling such sensitive materials. Heat pump dryers have been applied in the production of a diversity of ready-to-eat foods and dried instant products for the last five years at SINTEF-NTNU. Besides being energetically efficient and environmentally friendly, the heat pump drying technology provides a wide range of drying conditions as required to produce powders with improved characteristics. This work describes the new technologies and processing line for the production of instant foods as well as the measurements on the properties and quality attributes for raw, intermediate and final instant products.  相似文献   

19.
Technology and colour are viewed as interfaces between the environment, humans and human activity. Examples are provided of ways of facilitating and improving access to and use of colours by commercial users of colour coatings through improvements in the accuracy of measuring and displaying colour. By analogy, the task of providing effective interfaces within the coatings industry, between the coatings industry and the environment and between the coatings industry and the public and political domain are discussed. Examples of information shortfalls are cited to illustrate how distortions arise. Examples of more effective, integrated technological, organisational and political interfacing are culled from the author's experiences.  相似文献   

20.
[目的]探讨毒死蜱和联苯菊酯在室内外土壤中的消解动态,并预测2种农药作为土壤化学屏障防治白蚁的有效期。[方法]采用气相色谱法测定不同时期土壤中毒死蜱和联苯菊酯的残留量并采用土壤穿透法测定2种农药在土壤中的生物活性。[结果]毒死蜱在室内和室外的半衰期分别为51.3、39.5 d,联苯菊酯在室内和室外的半衰期分别为31.3、44.5 d。毒死蜱和联苯菊酯抗白蚁穿透的最低有效质量分数分别为6.15、5.78 mg/kg,并结合消解动态方程预测出毒死蜱和联苯菊酯作为土壤化学屏障中有效成分的有效期在室内分别为195、29.1 d,在室外则分别为158.4、56.1 d。[结论]得到的白蚁防治有效期结果较好,为白蚁的化学防治提供理论依据。  相似文献   

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