Thin-layer chromatography of simple urea-formaldehyde-methanol reaction products. Part II. Quantitative aspects

Abstract

A thin-layer chromatographic method for the determination of urea, monomethylolurea and dimethylolurea in urea-formaldehyde resins is described. The resin is treated with methanolic boron trifluoride, whereby the methylol compounds are quantitatively converted into their respective methyl ethers. Subsequent application of chromatography on silica gel plates that have been previously treated with ammonia vapour in order to prevent reaction of the urea derivatives results in the effective separation of the components of low relative molecular mass, thus allowing their concentrations to be determined. Examples are given illustrating the change in concentration of urea derivatives of low relative molecular mass with time in urea-formaldehyde formulations.