Novel approach on the synthesis of starch betainate by transesterification

Transesterification of starch with methyl betainate was studied for the first time, both in aprotic media and solid state, under alkaline acidic conditions. Betaine hydrochloride esterified methanol, attaining a conversion 86%. Starch then converted into either N,N-dimethylformamide or dimethyl sulfoxide, using sulfuric acid as catalyst pre-activating polymer NaOH/ethanol. Furthermore, solid-state transesterification carried out ball mill, which replaced less corrosive sulfamic acid. Cationic esters were characterised by 1H 13C NMR spectroscopy, infrared thermogravimetric analysis, viscometry, optical microscopy (in water) scanning electron (dry). In solution, process attained degrees substitution up to 0.4. No by-products, dehydration, oxidation colouring detected, but underwent severe depolymerization wet media. whilst resulting degree lower, degradation minimal. any case, transesterification, its variety possibilities, yields cationic starches that offer promising alternative conventional ethers.