(70b) Concentration and Mixing Effects On the Production of Amine Hydrochloride Salts in a Confined Impinging Jet Reactor

A Confined Impinging Jet Reactor (CIJR) was used to react 4, 4’-methylene dianiline (MDA) with hydrogen chloride (HCl) to determine whether methylene dianiline dihydrochloride (MDA.2HCl) and/or methylene dianiline monohydrochloride (MDA.HCl) form under various reaction conditions. The two aminehydrochloride (AHC) salts are byproducts of a desired reaction sequence in the manufacture of polyurethanes. The effects of several processing variables (local concentration of MDA and HCl) and the intensity of local mixing on the formation of AHC salts were studied. In almost all cases, solid precipitates formed. They were characterized using a wide range of analytical techniques: elemental analysis (EA), FTIR, TGA, DSC, Optical Microscopy, SEM and EDX. The most successful analytical methods and the effects of each process variable on the solids composition, thermal properties, morphology and average size are discussed. Results show that formation of AHC salts more than anything depends on local concentration of MDA and it dominates the structure of product in terms of formation of MDA.HCl or MDA.2HCl. Mixing intensity on the other hand, affects purity of product and evenness in shapes and average size of particles.