Synthesis and properties of thermoplastic propyl-etherified amylose

Amylose was etherified with 1-bromopropane in DMSO. The degree of substitution (DS) was varied by altering the feed ratio of 1-bromopropane. The structures of the products were characterized by IR and 1H-NMR spectroscopy. When the molar feed ratio of 1-bromopropane to hydroxyl groups of amylose was beyond 7.5, the hydroxyl groups were completely substituted with propyl ether groups. The etherified amylose with DS 1.9 showed a glass transition temperature (T_g), and that with DS 2.3 or 3.0 showed both T_g and melting temperature (T_m) (DS 3.0 means complete substitution). The etherification imparted melt processability and solubility in nonpolar organic solvent to amylose.     

Synthesis of multihydroxyl branched polyethers by cationic copolymerization of 3,3‐bis(hydroxymethyl)oxetane and 3‐ethyl‐3‐(hydroxymethyl)oxetane

The cationic ring‐opening polymerization of 3,3‐bis(hydroxymethyl)oxetane (BHMO) and the copolymerization of BHMO with 3‐ethyl‐3‐(hydroxymethyl)oxetane (EOX) were studied. Medium molecular weight polymers (number‐average molecular weight ≈ 2 × 10³) were obtained in bulk polymerization. Poly[3,3‐bis(hydroxymethyl)oxetane], as highly insoluble, was only characterized by gel permeation chromatography and NMR methods in the esterified form. Copolymers of BHMO and EOX that were slightly soluble in organic solvents were characterized in more detail. In a copolymerization from a 1:1 mixture, the comonomers were consumed at equal rates. Matrix‐assisted laser desorption/ionization time‐of‐flight analysis confirmed that a random 1:1 copolymer was formed. ¹³C NMR analysis indicated that in contrast to previously described homopolymers of EOX in which the degree of branching was limited, the homopolymers of BHMO were highly branched. This pattern was preserved in the copolymers; EOX units were predominantly linear, whereas BHMO units were predominantly branched. The copolymerization of BHMO with EOX provides, therefore, a route to multihydroxyl branched‐polyethers with various degrees of branching containing ? OH groups exclusively as ≡C? CH₂? OH units. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1991–2002, 2002     

An Ylide Transformation of Rhodium(I) Carbene: Enantioselective Three‐Component Reaction through Trapping of Rhodium(I)‐Associated Ammonium Ylides by β‐Nitroacrylates

The chiral Rh^I–diene‐catalyzed asymmetric three‐component reaction of aryldiazoacetates, aromatic amines, and β‐nitroacrylates was achieved to obtain γ‐nitro‐α‐amino‐succinates in good yields and with high diastereo‐ and enantioselectivity. This reaction is proposed to proceed through the enantioselective trapping of Rh^I‐associated ammonium ylides by nitroacrylates. This new transformation represents the first example of Rh^I‐carbene‐induced ylide transformation.     

静电场诱导十二烷基硫酸钠结晶行为的研究

用透射电镜、X射线衍射及DSC等方法 十二烷基硫酸钠（SDS）极稀水溶液（溶液介于临界聚集浓度和临界胶束浓度之间）在静电场作用下的结晶行为,静电场作用诱导SDS形成规则的四方单晶与从甲醇中重结晶所得样品的晶体结构相同,DSC结果表明,从有序到无序结构变化的一级相转变热焓相同,但由于电场诱导结晶的晶体较小而表现为转变温度的降低,没有施加静电场处理的样品只具有较低的有序程度。     

以硅胶为载体合成水不溶性季铵盐类杀菌剂

硅胶载体;水不溶性杀菌剂;以硅胶为载体合成水不溶性季铵盐类杀菌剂     

高取代度淀粉醋酸酯的制备

改善淀粉热塑性的方法主要是用塑化剂对其进行处理和用化学方法制备淀粉衍生物,使羟基被长链取代,减弱淀粉分子间的氢键,大分子可在较低温度下运动,从而达到降低熔融温度的目的。近年来,对高取代度淀粉醋酸酯已有报道^[1-5],Sagar等^[2]认为,粉酯的取代度越高,侧链越长,热塑性和亲水性的改变就越明显,而且酯基可起到内增塑作用,可塑性的提高反映在材料的流变学,热学及力学性能的改变上,Maheras等^[3]用高取代度的淀粉醋酸酯和纤维素醋酸酯共混,制成了纤维和塑料制品,由于高取代度淀粉醋酸酯熔点较高,Brochers等^[4]提出通过加入分子量为100－1000的增塑剂,如甘油三醋酯等,可使熔融温度降到150℃左右,Tanaka等^[6]将淀粉和乙烯类化合物在酯化催化剂的作用下反应,得到的淀粉酯性能较为理想,分子量高,具有相当好的机械性能和耐水性,国外专利报道了以甲磺酸（MSA）为催化剂制备淀粉醋酸酯的方法^[7},但对其结构和性能尚未作系统的研究,本文以冰醋酸和醋酸酐为混合酸,MSA为催化剂,制得了具有较高取代度的高直链淀粉醋酸酯,并系统研究了反应温度,反应时间,反应物比例等不同反应条件对取代度的影响,通过红外分析,特性粘度测试,溶解性等分析手段,表征了高直链淀粉醋酸酯的结构与性能。     

疏水淀粉衍生物的制备

淀粉酯化;长链烯基琥珀酸酐;疏水淀粉衍生物的制备     

碘—淀粉络合物褪色光度法测定微量氰化物

研究了在 p H 7.0的混合磷酸盐缓冲溶液条件下 ,氰根使碘与淀粉形成的蓝色络合物褪色 ,络合物吸光度的降低值 ΔA与加入的氰根量成正比。 λmax=570 nm,氰根在 0～ 2 0 μg/2 5ml范围内呈良好的线性关系 ,检出限为 0 .52μg/2 5ml,其表观摩尔吸光系数为 2 .6× 1 0 4 ,方法成功地用于含氰废水中氰化物的测定。     

非抑制型离子色谱法测定碱金属、铵离子和烷基胺

 采用非抑制型离子色谱法、以氨磺酸作流动相分离测定了Li+ 、Na+ 、NH+ 4、K+ 、甲胺、乙胺和正丙胺等 7种物质 ,研究了氨磺酸流动相浓度对溶质保留值的影响。结果发现 ,随着流动相浓度的增大 ,溶质保留值减小 ;适宜的流动相浓度为 4 0mmol/L。以 4 0mmol/L氨磺酸为流动相测得上述 7种物质的检出限及工作曲线的线性回归方程。方法应用于自来水试样的分析 ,结果良好。     

硫酸铁铵催化合成肉桂酸酯

利用十二水合硫酸铁铵为催化剂,使肉桂酸与醇类发生酯化反应合成了肉桂酸甲酯、肉桂酸乙酯、肉桂酸正丙酯、肉桂酸正丁酯、肉桂酸异丁酯、肉桂酸正戊酯和肉桂酸异戊酯,测定了各种酯的沸点（或熔点）折光率、元素组成和IR。