4.2 Chemical characteristics of cellulose acetate

The chemical structure of cellulose acetates (CA), different synthesis paths, analysis strategies and the correlation of these structural features with properties, especially with the solubility are summarized. Alternative paths, in particular homogeneous procedures, for the synthesis of CA are described focusing on the application of new media and the in situ activation of acetic acid. The preparation of selectively substituted CA is reviewed including the defined hydrolysis under acidic or basic conditions. Strategies for the structure analysis by means of ¹H- and ¹³C-NMR spectroscopy and by means of chromatographic methods are discussed. In addition, the preparation and the application of a variety of mixed CA ethers and esters are described.     

1, 2λ5-azaphosphinines and a new 1λ5, 3λ5-. Diphosphinine

The 1,2-azaphosphinine, 9 , and the 1,3-diphosphinine, 10 , can be isolated from a mixture resulting from the reaction of 1,1,3,3-tetrakis(dimethylamino)-1λ⁵,3λ⁵-diphosphete, 1 , and ethyl isothiocyanate. The reaction of 1 with phenyl isothiocyanate yields the 1,2-azaphosphinine, 16 . Mechanisms for the formation of the compounds 9 , 10 , and 16 are suggested. The properties, the NMR, mass, and IR spectra, and the molecular and crystal structures of 9 and 10 are described and discussed.     

The first report on a convenient synthesis of novel reactive amphiphilic polysaccharides

New amphiphiles with reactive tosylate groups and ionic sulfuric acid half esters based on the rod-like polysaccharide cellulose were designed via homogeneous tosylation followed by sulfation with the SO₃-pyridine complex in N,N-dimethylacetamide. At appropriate degrees of functionalization the polymers are soluble both in water and dimethyl sulfoxide, and they are promising starting materials for self-organizing systems.