Preparation and optimization of macroalgae-derived solid acid catalysts

Solid acid catalysts were synthesized from macroalgae Sargassum horneri via hydrothermal carbonization followed by sulfuric acid sulfonation. A three-variable Box-Behnken design and optimization was used to maximize surface acidity. The optimal preparation conditions were found to be at the carbonization temperature of 217 °C, the carbonization time of 4.6 h and the sulfonation temperature of 108.5 °C. Under these conditions, the highest surface acidity achieved was 1.62 mmol g−1. Physical and chemical properties of prepared solid acid catalyst were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, and elemental analysis. The results proved the grafting of –SO3H groups on an amorphous carbon structure. The catalyst activity was evaluated by the esterification of oleic acid with methanol. The sample prepared achieved 96.6% esterification yield, which was higher than the 86.7% yield achieved by commercial Ambersyst-15 under the same reaction conditions

Comparison of the physico-chemical characteristics, oxidative and hydrolytic stabilities of oil and fat of cyperus esculentus L. (yellow nutsedge) and butyrospermum parkii (shea nut) from Middle-Belt States of Nigeria

The physico-chemical characteristics, oxidative and hydrolytic changes during storage and accelerated conditions of yellow nutsedge oil and shea fat were studied and comparisons made on the variables. The solvent extract of yellow nutsedge gave an oil yield of 22.3% and that of shea nut gave a fat yield of 52%. The saponification value, non-saponifiable matter, iodine value, refractive index (at 250°C) and colour were 188mg KOH/g, 0.5%, 104.8, 1.4672, and golden yellow respectively for yellow nutsedge oil while for shea fat they were, 191mg KOH/g 3.01%, 59.5, 1.4675 and milky white respectively. The hydrolytic changes occurring over 9 weeks period for solvent extract of yellow. Keywords: physico-chemical characteristics, cyperus spp, oil and fat, NigeriaNigerian Food Journal Vol. 23 2005: 33-3