FORMATION AND REACTIONS OF METHYLOL CELLULOSE

The mechanism of cellulose dissolution via the formation of methylol cellulose together with the derivatization of the dissolved methylol cellulose were investigated.; Elucidation of how dimethyl sulfoxide participates in the formation and dissolution of methylol cellulose in the dimethyl sulfoxide/paraformaldehyde (DMSO/PF) solvent system resulted in the discovery that methylol cellulose could also be prepared and dissolved in solvents other than DMSO. The solvents which were found to be successful have the common characteristics of being dipolar, aprotic, and good hydrogen bond acceptors. Solvents found to be successful include pyridine, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N-methyl-2-pyrrolidinone (NMP) and tetramethylene sulfoxide (TMSO).; Preparation of the peracetate of methylol cellulose was accomplished using acetic anhydride and pyridine. Acetylation of the methylol substituents provided a stable acetal derivative which could then be isolated and characterized by NMR spectroscopy. NMR analysis of the acetate derivative provided direct evidence for the methylol derivative and demonstrated the existence of polyoxymethylene substituents. NMR analysis of the peracetate is a convenient experimental technique for determining the molar degree of substitution (MS) of methylol cellulose.; Analysis of the MS of methylol cellulose prepared in the various solvents demonstrated that a high MS is required initially to accomplish dissolution. However, once the cellulose has dissolved, the MS can decrease substantially and still retain the cellulose in solution. The MS required to obtain dissolution and the minimum MS required to keep the cellulose in solution are dependent on the organic solvent which is employed.; Hydroxyethylation of methylol cellulose in the DMSO/PF system was attempted. Chemical analysis of the reaction product indicated small amounts of substitution had been obtained. Gas-liquid chromatographic (GLC) analysis showed no detectable amounts of substitution on the anhydroglucose units of the cellulose. Substitution by the hydroxyethyl groups most likely occurred at the hydroxyl groups of the methylol substituents and were subsequently lost during the acid hydrolysis prior to GLC analysis.; The homogeneous preparation of triphenylmethyl (trityl) cellulose is easily and rapidly accomplished in the methylol cellulose solvent systems. At a reaction temperature of 80(DEGREES) in the presence of pyridine with excess reagent, the methylol substituents are displaced, thus giving trityl cellulose with a degree of substitution (DS) of 1 as the final product. An intermediate product, trityl methylol cellulose, was isolated which indicates that displacement of the trityl methylol acetal substituents occurs. A by-product of this reaction was a new compound, triphenylmethoxymethyl pyridinium chloride.