丙烯酸与淀粉微波固相接枝共聚反应研究

自由基共聚是淀粉接枝共聚的主要形式,常用的方法有化学引发和Co60辐射引发等。目前这些方法多数都必须在通氮除氧的条件下进行,而且多数体系因含水或溶剂需干燥、洗涤等后处理,使成本增加[1]。固相接枝共聚反应目前报导不多[2]。本文研究了微波辐射下丙烯酸与玉米淀粉的固相接枝共聚反应并得到了比较满意的结果。目前这方面的研究国内外尚未见报导。1　实验部分1.1　原料与仪器玉米淀粉,市售,一级,使用前在真空烘箱中干燥至恒重;丙烯酸(AA),化学纯,使用前经减压蒸馏精制;引发剂过硫酸铵(APS)、过氧化二苯甲酰(BPO),均为化学纯,经重结晶…     

"微波固相法"合成羧甲基淀粉及其助洗性能的研究

羧甲基淀粉(CMS)是一种重要的淀粉衍生物,在医药、食品、纺织、印染、洗涤剂、印刷、造纸、冶金、石油钻井等方面有广泛用途。CMS的合成方法有传统的水媒法、溶媒法以及固相法。这些方法各有优缺点：水媒法一般不能生产取代度大于0．1的产品,溶媒法则需要大量有机溶剂,生产成本较高,而且它们都需要较长的反应时间,固相法反应受热不均匀。为此采用微波固相法合成CMS,同时,研究了产品的助洗性能,并与溶媒法比较,结果基本一致。     

微波加热法快速合成T型分子筛

由于具有高的水热稳定性和优良的孔道结构．T型分子筛已成为一种高选择性的催化剂．在低碳化合物的催化和重整等方面有较多的应用。近年来．报道采用晶种法在无机多孔陶瓷支撑体上制备的T型分子筛膜．在脱除有机物／水混合物中的水时．表现出优异的渗透汽化分离性能。然而，提高T型分子筛膜的致密性和生长速率仍是亟待解决的问题。T型分子筛的合成研究较少．制备过程均采用普通加热（Conventional Heating．CH）法。在无模板剂的条件下．T型分子筛的结晶区间较窄，结晶速率慢．合成时间通常需要6d以上。     

微波辐射固相法合成缩二脲铜配合物

The copper(Ⅱ) complexes of biuret have been synthesized by solid phase reaction with microwave irradiation. The compositions and structures of the complexes are characterized by elemental analysis, molar conductance, in-frared spectra, electronic spectra, magnetic susceptibility, thermogravimetric and differential thermal analysis, X-ray powder diffraction. The two complexes have the compositions of [Cu(bi)₂]Cl₂(A) and [Cu(bi)₂](NO₃)₂(B)(bi=NH₂CONHCONH₂) and the molecular formulae of CuC₄H₁₀O₄N₆Cl₂ and CuC₄H₁₀O₁₀N₈, respectively. The molar conductance data show that the complexes are 1∶2 electrolyte. Infrared spectra of the complexes show oxygen atoms have been coordinated with divalent copper ion. The thermal decomposition processes of the complexes show that the final residues are all cupper oxide. The results of indexes to the X-ray powder diffraction data indicate that the crystal structure of the complexes belong to monoclinic system, the lattice parameters are: a=0.6976nm,b=1.1546 nm,c=2.1689nm,β=96.80°,V=1.7346nm³ for A; and a=0.7096nm,b=1.1359 nm,c=2.1002 nm,β=97.05°,V=1.6800nm³ for B, respectively.     

微波固相法合成层状磷锑酸钾化合物

应用微波合成技术, 以石墨或三氧化二铁为加热介质, 合成了两种新的层状磷锑酸钾: KSbP2O8, K3Sb3P2O14。与传统固相反应相比较(典型合成条件为:950~1000℃下、24h), 微波法可在微波辐射下(2.45 GHz), 仅在40~90分钟内使反应完成。在详细研究相转变的同时, 对微波在固相合成中的作用进行了初步的讨论。     

甘氨酸钙螯合物的微波固相合成与表征

以甘氨酸(Gly)和氧化钙为原料,用微波固相化学法合成了甘氨酸钙螯合物。正交试验确定了最佳工艺条件：Gly7．50g(100mmol),n(Gly)：n(氧化钙)=1．00：0．70,研磨20min,辐射1min,研磨辐射3次,产率95.1％。并用元素分析,IR,TG-DTA,X-射线粉末衍射对螯合物进行了表征,确认其组成为[Ca(Gly)2]H2O。     

微波辅助固相有机反应

固相有机合成是组合化学中构建化合物库的主要工具之一［１,２］,但是,由于它是连接在固相载体（如树脂等）上的试剂与溶解在有机溶剂中的试剂之间的反应,因此反应比较缓慢．考虑到微波技术对有机反应的协助作用,我们将微波技术应用到固相有机反应中,对比研究了微波...     

淀粉磷酸酯粘度性质的研究

本文研究了淀粉磷酸酯(PS)的粘度性质,包括剪切应力和剪切速率之间的关系、粘度和剪切速率之间的关系、浓度对粘度的影响、粘度对温度的依赖性,以及粘度的时间稳定性,并且与羧甲基淀粉(CMS)和羧甲基纤维素(CMC)水溶液的粘度性质作了比较。结果表明,PS的粘度与CMS或CMC相近似;在浓度为0.5～1.5％时增稠效果较显著;CMC具有较高的剪切稳定性,PS次之,而CMS较差;PS具有较长的时间稳定性,但热稳定性则较差。     

固相载体法合成低聚糖

固相载体法合成低聚糖;固相载体;合成;低聚糖;偶联剂     

微波加热法测定粮食中的水分

采用微波加热法测定粮食中的水分，测定条件是：微波功率700w、加热时间8min。测定结果的标准偏差为0．023％～0．047％(n=5)。该方法操作简便，分析时间短，分析结果准确、可靠。     

马铃薯淀粉磷酸酯的物理化学特性

通过与玉米淀粉和马铃薯淀粉相比较,研究了马铃薯淀粉磷酸酯（PEPS）的理化特性,包括粘度的测定,热糊与冷糊的稳定性,不同pH值及电解质（NaCl)和非电解质（蔗糖）存在下的粘度曲线,凝胶强度及冻融稳定性,结果表明,马铃薯淀粉磷酸酯比玉米淀粉和马铃薯淀粉具有更优良的热糊与冷糊的稳定性,电解质(NaCl）和非电解质（蔗糖）的存在,对其热糊与冷糊的稳定性基本元影响,凝胶强度高,冻融稳定性好,尤其是耐酸性能强。     

Synthesis of Compact NaA Zeolite Membrane by Microwave Heating Method

A continuous and dense NaA zeolite membrane was synthesized by microwave heating method while employing a multi-step seeding LTA zeolite with the average size of 120 rim. The gas H2/N2 mixture separating results indicated that the mixture selectivity increased with increasing of synthesis times. In addition, selectivity of the three-step synthesis was higher than the value(3.74) expected from Kundsen diffusion.     

An Efficient and Environmentally Friendly Method for the Synthesis of Cellulose Carbamate by Microwave Heating

An efficient, solvent‐free, and catalyst‐free microwave synthesis of cellulose carbamate from a mixture of native cellulose and urea is reported. The structure of the samples are characterized by elemental analysis, FT‐IR spectroscopy, X‐ray diffraction, and NMR spectrometry. Cellulose carbamates with a nitrogen content of 0.651–2.427% are obtained by microwave heating at 255 W for 2–5 min. With the introduction of carbamate groups, the hydrogen bonding and crystalline structure of the native cellulose are partially destroyed. The products retain the cellulose I crystalline form of the native cellulose, and display good solubility in NaOH solutions.

     

纳米结构羟基磷灰石的微波固相合成新方法

本文报道了一种简单的室温下微波辅助合成羟基磷灰石(HAP)的新方法。与常规方法相比，该方法具有反应条件温和、反应时间极短的优点。合成中，以Ca(NO₃)₂·4H₂O和Na₃PO₄·12H₂O为原料，经过研磨和微波加热得到了HAP纳米粒子和纳米棒。用XRD、FTIR，BET和SEM等对产物进行了表征。在反应过程中，微波辐射作为一种加热处理手段对HAP的形成起到非常重要作用。同时     

微波场中A型分子筛及分子筛膜合成的研究

Effects of aging time and alkalinity as well as cation concentration(Na⁺) on the synthesis of A type zeolite and zeolite membrane were investigated in this paper. The results showed that aging time for synthesis of A type zeolite and zeolite membrane had remarkable influence and alkalinity could accelerate the formation of zeolite but was disadvantage to zeolite membrane synthesis. Cation concentration(Na⁺) also couldn′t accelerate the synthesis of zeolite and zeolite membrane but it was probable an important factor to accelerate crystal growth .Moreover, more compact zeolite membranes could be synthesized by this method while the thickness of membrane was thinner than that of convention. Zeolites and zeolite membranes were characterized by XRD, TEM as well as IR characterization techniques.     

Application of Microwave Heating Technique to Esterification

Introduction Although the application of microwave technique has been reported as a new type of energy source chemically, it is only in recent years that this technique has been used as the energy source for organic synthesis. In 1986, R. Gedye, et al., published the report of the benzoate synthesis from the respective reactions between benzene carboxylic acid and methanol, propanol or butanol under microwave heating and the catalysis of H_2SO_4.     

微波场中T型分子筛的合成及晶化研究

研究了微波场中T型分子筛的结晶过程。考察了微波加热体系中合成参数如合成时间、溶胶组成、反应压力和模板剂用量对分子筛晶化的影响。微波加热的主要优点是减少合成时间,无模板剂的溶胶在普通加热条件下的晶化时间需要120 h,而在微波场中则仅需要20～25 h。另一方面,由于微波的快速加热特性促进了稳定相钙十字沸石的生成,从而减小了次稳定相T型分子筛的结晶区间。在未添加模板剂条件时,100 ℃下微波水热合成T型分子筛的结晶区间为：20≤n_SiO2/n_Al2O3≤22和0.31≤ n_M2O/n_SiO2≤0.33(其中M₂O=Na₂O+K₂O, n_Na/n_K=3和n_M2O/n_SiO2=11.70)。在普通加热和微波加热合成体系中,添加模板剂均能扩大结晶区间,同时还可以进一步减少合成时间。     

Template-Free Synthesis of AlPO 4 -H1 by Microwave Heating

Microwave heating enhanced the crystallization of aluminophosphate gels, and AlPO 4 -H1 was successfully obtained without using organic template reagents in a short reaction time. The use of amorphous aluminum hydroxide as an aluminum source and the addition of hydrochloric acid were found to be essentially important to obtain AlPO 4 -H1 as a single phase. Nitrogen and water adsorption properties were studied by measuring the adsorption isotherms.     

微波法合成S-苄基半胱氨酰甘氨酸乙酯

微波条件下,溴化氢醋酸对S-苄基-N-苄氧羰基半胱氨酰甘氨酸乙酯(1)进行脱保护反应,合成了S-苄基半胱氨酰甘氨酸乙酯(2).最佳反应条件为:1 2.9 mmol,n(1):n(HBr-AcOH)=1:6,微波功率200 W,于30 ℃辐射20 min,2的收率为87%.其结构经~1H NMR和IR表征.