- PROCESS FOR SPLITTING WATER-SOLUBLE ETHERS
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A process for production of 1,3-propanediol including the steps: (a) hydrating acrolein in the presence of an acid hydration catalyst; (b) catalytically hydrogenating the reaction mixture of step (a), which reaction mixture comprises 3-hydroxypropionaldehyde and is freed of unreacted acrolein; (c) refining the reaction mixture of step (b) containing water, 1,3-propanediol and the by-products boiling higher than 1,3-propanediol; and (d) treating 4-oxa-1,7-heptanediol to form 1,3-propanediol by (1) removing a boiler sump comprising 4-oxa-1,7-heptanediol from the refining step (c), (2) treating the boiler sump in an aqueous solution in the presence of an acid catalyst at about 200 to about 300° C. to form a solution comprising 1,3-propanediol, (3) neutralizing the solution obtained is step (2), and returning the neutralized solution from step (3) to the refining step (c). In addition, a process for splitting oligomeric water-soluble ether comprising: (a) treating an aqueous solution comprising oligomeric water-soluble ether in the presence of homogeneous acid catalyst at a temperature of from about 200 to about 300 ° C. to form the monomer of the oligomeric water-soluble ether; and (b) neutralizing the solution obtained in step (a),
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- 13C-N.M.R.-SPECTRAL AND RELATED STUDIES ON THE DISTRIBUTION OF SUBSTITUENTS IN O-(2-HYDROXYPROPYL)CELLULOSE
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Information about the degree of substitution at individual oxygen atoms of O-(2-hydroxypropyl)cellulose, and the total molar substitution, was obtained from 13C-n.m.r. spectra of the intact polymer and of its hydrolyzate.On the basis of their 13-CH3 chemical-shifts, O-(2-hydroxypropyl) (HOPr) substituents occurring singly, or as terminal units of substituent chains, were radily distinguished from inner HOPr units of chains.Differentiation between monomeric HOPr units and longer chains located at O-2 of D-glucosyl residues was effected by the transformation of appropriatly substituted sugars in the hydrolyzate into 1,2-cyclic acetals incorporating a 2-O-(2-hydroxypropyl) group.Similarly, the pattern of substitution at O-6 of D-glucosyl residues was determined, through selective degradation, from the identity of HOPr derivatives of ethylene glycol, representing C-5 and C-6 of the residues.Overall, it was found that, although O-2 and O-6 are more readily substituted than O-3, the rate at which each, initially introduced, HOPr substituent is converted into a dimeric structure is not materially affected by its location.Also described are the synthesis and the n.m.r. spectra of several HOPr derivatives of D-glucose, and of simple alkanols that served as model compounds.
- Lee, Dae-Sil,Perlin, Arthur S.
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