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| | Alkaline and acid hydrolyses of polyacrylamide have been studied.Hydrolyses caused by dilute alkali or dilute acid were found to beincomplete, while those by concentrated alkali and acid approaching completeness.In the range of 0.6--3.3 N sodium hydroxide and at 100℃, the limiting degreeof hydrolysis is around 65--70%. It was found that Van Slyke method couldbe applied to the quantitative determination of the amide group in the polymerswhile the nitrile groups causing no interference. The identity period of... | | 本文报告聚丙烯酰胺的硷性水解及酸性水解。用浓酸或浓硷处理,都可接近完全水解,用稀酸或稀硷水解则不完全。在0.6~3.3N氢氧化钠及100°时,水解程度为65—70%,Van Slyke法可用以测定丙烯腈与丙烯酰胺共聚物中酰胺基量。用X-射线衍射法测定聚丙烯酰胺长链的等同周期为5.2A。硷性水解之不完全,主要是由于邻近羧基的负电场对羟基向酰胺基进攻时的屏蔽作用所致。合成丙烯酰胺分别与丙烯酸、丙烯醇、或乙酸乙烯酯的共聚物,从而研究其硷性水解,前者的水解限度为75%,后二者可以接近完全,直接证明邻近非负性基团不能产生负电场因而没有屏蔽作用,故水解接近完全。研究若干N取代聚丙烯酰胺及共聚物的水解,在一定条件下它们的水解程度按下列次序递减:聚丙烯酰胺>聚N-甲基丙烯酰胺>聚N,N-二甲基丙烯酰胺>聚N,N-二乙基丙烯酰胺。除了邻近负电场的屏蔽作用外,N及N,N-取代基在长链中有不容忽视的空间阻碍。 | | 文摘来源 | | The rate of hydrolysis (k) of methyl N-acetyl-2-amino-2-deoxy-α-D-gluco-side (Ⅲ), methyl N-benzoyl-2-amino-2-deoxy-α-D-glucoside (Ⅴ), methyl-α-D-glucoside (Ⅸ), α- and β-anomers of methyl N-(2', 4'-dinitrophenyl)-2-amino--2-deoxy-D-glucoside (Ⅶ, Ⅷ) in 0.5 N NCl solution at 75°±0.2℃ have beenstudied. The degree of hydrolysis was determined by quantitative estimation of thereducing sugars liberated. Glucose and N-(2',4'-dinitrophenyl)-2-amino-2-deoxy-D-glucose (Ⅵ) were determined by Willstatter-Schudel method,... | | 在75°±0.2°的温度、0.5N盐酸溶液中,N-乙酰-2-胺基-2-脱羟-D-葡萄糖-α-甲基甙(Ⅲ)、D-葡萄吡喃糖-α-甲基甙(Ⅸ)、N-二硝苯-2-胺基-2-脱羟-D-葡萄糖-α-甲基甙(Ⅶ)的水解速率k×10~4分别为11.70、7.21、1.91、1.44、0.41分~(-1)。如以D-葡萄吡喃糖-α-甲基甙的k_Ⅸ(1.91×10~(-4))为100,则k_Ⅲ:k_Ⅴ:k_Ⅸ:k_Ⅷ:k_Ⅶ=612:377:100:75:21。N-苯甲酰胺键与二硝苯基胺键在酸性水解中相当稳定,在三小时内无自胺基上脱落的现象 | | 文摘来源 | | Five new 7-oxo-alkanoic acids,R-CO-(CH2)6-COOH (Where R=CH3-(CH2)13,CH3(CH2)15,CH3(CH2)17,CH3(CH2)20 and CH3(CH2)32),have been prepared by the reaction of carboxylic chlorides with 1-morpholino-1-cyclohexene.The acids thus formed were reduced twice by first Huang-Minion modification of the Wolff-Kishner method and then lithium aluminum hydride,giving the corresponding higher primary alkanols.We studied the necessary conditions of the reaction of long chain acyl chlorides with 1-morpholino-l-cyclohexene in t... | | 本文由正-二十四烷酸与五氯化磷反应,得到的二十四烷酰氯在氯仿中和三乙胺存在下与1-吗啉-1-环己烯反应所得中间体,经酸性水解,碱性开环和酸化,得到7-氧代-三十烷酸,而据文献报导[7],正-二十四烷酞氯与1-吗啉-1-环己烯反应结果,得到的仍然是原料二十四烷酸。 作者采用上述方法合成了五种新的7-氧代烷酸R—C—(CH~2)~5—COOH(R=n-C_(14)H_(29),n-C_(16)H_(33),n-C_(18)H_(37),n-C_(21)H_(43)和n-C_(23)H_(47))。 所制得的7-氧代三十烷酸经黄鸣龙改良的开息纳尔-武尔夫还原,再经四氢锂铝还原,即得三十烷醇。 | | 文摘来源 | |   | | << 更多相关文摘 |
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