The solubility and the primary nucleation kinetics of pentaerythritol (PE) at 98% and 94% purity in aqueous solution were investigated in the range 20-80 degrees C, and the effect of adding 1% formaldehyde or 2% formic acid was also examined. The solubility increases with decreasing purity of the product and on adding the cited compounds to the solution. The nucleation kinetics exhibit high values of nucleation order, ranging from 32 to 10 for nucleation temperatures in the range 19-61 degrees C; that is, the generation of nuclei becomes significant only after exceeding a threshold value of supersaturation, which increases as the temperature decreases. The primary nucleation rate increases strongly with the temperature, while it decreases on decreasing the purity of the product and on adding formaldehyde and formic acid to the solution. The hypothesis is suggested that some impurities, accompanying the 'pure' product also and adsorbed more strongly at low than at high temperature, may inhibit the growth rate of the solute aggregates to nuclei size, thus depressing the nucleation kinetics.
Nucleation kinetics of pentaerythritol / Chianese, Angelo; M., Karel; Mazzarotta, Barbara. - In: THE CHEMICAL ENGINEERING JOURNAL AND THE BIOCHEMICAL ENGINEERING JOURNAL. - ISSN 0923-0467. - STAMPA. - 58:3(1995), pp. 209-214. [10.1016/0923-0467(94)02896-6]
Nucleation kinetics of pentaerythritol
CHIANESE, Angelo;MAZZAROTTA, Barbara
1995
Abstract
The solubility and the primary nucleation kinetics of pentaerythritol (PE) at 98% and 94% purity in aqueous solution were investigated in the range 20-80 degrees C, and the effect of adding 1% formaldehyde or 2% formic acid was also examined. The solubility increases with decreasing purity of the product and on adding the cited compounds to the solution. The nucleation kinetics exhibit high values of nucleation order, ranging from 32 to 10 for nucleation temperatures in the range 19-61 degrees C; that is, the generation of nuclei becomes significant only after exceeding a threshold value of supersaturation, which increases as the temperature decreases. The primary nucleation rate increases strongly with the temperature, while it decreases on decreasing the purity of the product and on adding formaldehyde and formic acid to the solution. The hypothesis is suggested that some impurities, accompanying the 'pure' product also and adsorbed more strongly at low than at high temperature, may inhibit the growth rate of the solute aggregates to nuclei size, thus depressing the nucleation kinetics.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
