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  • 1950-1954  (4)
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  • 1
    Electronic Resource
    Electronic Resource
    Chemical changes produces in the cellulose macromolecule by oxidizing agents (1953)
    Springer
    Russian chemical bulletin 2 (1953), S. 341-350 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. A study has been made of the composition of oxycelluloses obtained by oxidation with hydrogen peroxide in acid, neutral, and alkaline media. 2. It has been shown that chemical modification of the cellulose and fall in degrees of polymerization occurs at all values of pH, though in varying degree: oxidation proceeds most intensively in strongly alkaline (pH 〈) and in acid (pH 〉 4) media. 3. In the oxidation of cellulose by hydrogen peroxide the same chemical processes occur as in the oxidation of the simplest sugars, namely: the primary OH groups are oxidized to aldehyde and carboxyl groups; secondary OH groups are oxidized with formation of ketone groups and oxidation of 2,3-glycol groupings with rupture of the ring yielding two aldehyde groups, which may be converted further to carboxyls. The introduction of a catalyst(Fe++) accelerate the oxidation processes, particularly those leading to rupture of the pyran ring with formation of nonuronic carboxyls. 4. Certain differences are to be observed between the chemical composition and properties of oxycelluloses obtained by hypochlorite and by peroxide oxidation. The most important cause of these appears to be the breakdown of the glycol groupings into two aldehyde groups, a reaction that has not yet been shown to occur in oxidation with hypochlorites. 5. Owing to the occurrence to a marked extent of the latter type of oxidation with rupture of the pyran ring, the variety of new functional groups formed in the cellulose macromolecule during its oxidation by hydrogen peroxide is even greater than in hypochlorite oxidation: under all pH conditions groups will be formed that reduce the stability of the glucoside linkages in acid and alkaline media and so induce chain-breakdown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01171007
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  • 2
    Electronic Resource
    Electronic Resource
    Addition of dialkylphosphorous acids and of their acid chlorides toα-epoxides (1952)
    Springer
    Russian chemical bulletin 1 (1952), S. 837-842 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. It has been shown that dimethylphosphorous and diethylphosphorous acids add to, ethylene oxide, 1,2epoxycyclohexane; and 1,2-epoxy 3-ethoxypropane in presence of small amounts of boron tr fluoride etherate with formation of the corresponding esters of 2 hydroxyalkylphosphonic acids. When sulfuric acid or sodium diethyl phosphite is used as catalyst, the addition products are formed in low yield. 2. Diethyl and -ethylene phosphorochloridites add readily to ethylene oxide, to 2,3-epoxybutane, and to 1,2epoxycyclohexane. In the reaction between diethyl phosphorochloridite and ethylene oxide or 2,3-epoxybutane, the main product -2-chloroethyl diethyl phosphite (or 2-chloro-i-methylpropyl diethyl phosphite) -was accompanied by by-products -triethyl phosphite and bis(2-chloroethyl) ethyl phosphite (or tris(2-chloro-l-methylpropyl)ethyl phosphite) -formed by a process of disproportionation during the reaction. In the addition reactions between diethyl phosphorochloridite and 1,2-epoxycyclohexane and between ethylene phosphorochloridite and ethylene oxide, a single addition product was obtained in each cases 2-chlorocyclohexyl diethyl phosphite (66% yield) and 2-chloroethyl ethylene phosphite (95% yield).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01198874
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  • 3
    Electronic Resource
    Electronic Resource
    Chemical changes produced in the cellulose macromolecules by oxidizing agents (1952)
    Springer
    Russian chemical bulletin 1 (1952), S. 199-204 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. The causes of the non-accord in determination of total and uronic carboxyls in oxycelluloses prepared by the action of NaOCl in acid and neutral media have been elucidated. 2. it has been established that these causes are 1) the participation in reaction of lactonized carboxyls and 2) the presence in these oxycelluloses of a small proportion of carbonic ester groups. 3. The carbonic ester groups in oxycelluloses are very unstable, being readily hydrolysed by dilute alkali in the cold and by acids on warming. The presence of these groups is one of the contributing causes of the high instability towards alkalis of oxycelluloses formed by oxidation in an acid medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01176590
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  • 4
    Electronic Resource
    Electronic Resource
    Chemical transformations of cellulose macromolecules caused by oxidants Part 7. Chemical transformations of cellulose due to its oxidation with sodium hypochlorite (1952)
    Springer
    Russian chemical bulletin 1 (1952), S. 681-690 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. Chemical changes in the structure of cotton cellulose due to oxidation with sodium hypochlorite at different pH have been investigated by means of specific quantitative micromethods. 2. The following groups have been found in the oxycellulose obtained by hypochlorite oxidation: uronic and non-uronic carboxylic groups, C8 aldehydic groups,α-hydroketonic and lactone groups, and carbonic acid ester (ether) groupings. 3. The oxycelluloses obtained by oxidation in acid and neutral solution have a similar structure, different from that obtained in alkaline solution. 4. A reaction mechanism is advanced for the oxidative degradation of cellulose by action of sodium hypochlorite at various pH. This mechanism satisfactorily explains the chemical behaviour of the oxidation products. 5. The various oxidative processes shown to occur may be utilized for the better control of such processes, and for the preparation of cellulose oxidation products of known properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01164938
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