Verfahren zur Steuerung der Partikelgröße in der Kristallisation von Dimethylolalkansäuren

摘要

The invention relates to a method for the selective crystallization of poly- or monomethylol alkanoic acids of the general formula (I), wherein R is the same or different and represents a methylol group or a substituted or unsubstituted aliphatic hydrocarbon, with an essentially monomodal particle size distribution. This particle size distribution is achieved by crystallization in a temperature interval of from 85 DEG C to 50 DEG C observing a cooling rate of < 10 K/h, resulting in substantially trigonal-symmetric crystals. The invention further relates to a method for the selective crystallization of poly- or monomethylol alkanoic acids of the general formula (I), wherein R is the same or different and represents a methylol group or a substituted or unsubstituted aliphatic hydrocarbon, with an essentially monomodal particle size distribution. Crystallization is carried out at a temperature of