PREPARATION OF FINE MANGANESE OXIDIC PARTICLES VIA HYDROLYSIS OF A MULTINUCLEAR MANGANESE COMPLEX

Fine manganese oxidic species have been prepared by hydrolysis of a tr inuclear manganese complex [Mn3O (CH3COO)6(pyr)3]ClO4. The obtained pa rticles possess a high BET-specific surface area 150-200 m2 g-1 betwee n 200 and 400-degrees-C, which drops to 50 m2 g-1 at 500-degrees-C. TG studies showed that the dried material (110-degrees-C) loses approxim ately 10% of its weight between 100 and 200-degrees-C. Thereafter and between 200 and 500-degrees-C, a constant rate of weight loss appears, totaling around 3.5%. The material appears amorphous in XRD in the hi gh-surface-area region (T < 400-degrees-C) and crystalline thereafter. Adsorption-desorption of N2 at T = 77 K showed a hysteresis loop, cha racteristic of mesoporous solids. SEM photographs indicated the existe nce of particles of size 0.1-0.2 mum. (C) 1994 Academic Press, Inc.