Esterification of Mixed Carboxylic-fatty Anhydrides Using Amberlyst-15 as Heterogeneous Catalyst.
The article deals with the use of mixed anhydrides for the synthesis of fatty esters. Both aliphatic and aromatic acids are involved, indicating different behaviors according to the chain length of the aliphatic acid. We describe a novel and efficient method for the synthesis of fatty esters by the esterification reaction of primary, secondary and tertiary alcohols with mixed carboxylic-palmitic anhydrides using resin Amberlyst-15 as heterogeneous acid catalyst. Influence of various reaction parameters such as molar ratio (anhydride/alcohol), catalyst amount, type of alcohol and type of mixed anhydride were studied to optimize the conditions for maximum yield. Among tested anhydrides we quote mainly the 4-chlorobenzoic palmitic anhydride because it was both reactive and selective for the preparation of palmitic acid ester. This anhydride gave a good yield of palmitic ester.
Synthesis of Biosurfactants: Enzymatic Esterification of Diglycerol and Oleic Acid. 1. Kinetic Modeling
The growing application of environmentally friendly products raised in the last few years has increased the interest in biodegradable nonionic surfactant products. As an example of these, polyglycerol fatty acid esters have a wide field of application in many industries as additives of cosmetics, food, photography, inks, etc. Also, the huge range of possible raw materials for these products increases cited interest. The esterification of diglycerol with oleic acid using an enzyme (NOVOZYM-435) as catalyst was studied in this work. Several experiments were carried out at different temperatures, catalyst concentrations, and acid/alcohol molar ratios. A pseudo-second-order kinetic model, including Langmuir adsorption factors for the acid, was developed. The results show that this proposed kinetic model reproduces the experimental data with a maximum 10% error.
AN INTRODUCTION T O THE SOILS OF THE SOUTH-EASTERN PORTION OF THE AUSTRALIAN ARID ZONE
Summary 
 
Seven soil regions, each of which is dominated by soils belonging to one or two great soil groups, are defined and mapped. The outstanding feature is the presence of a variety of soils with widely differing characteristics. The soils are deeper, have more profile differentiation and are finer-extured than those in most-arid regions and are frequently overlain by currently-forming deposits of wind-transported materials. Because the vegetative cover is better developed and there are only small areas of rocky hills and bare rock pediments, water erosion and deposition are not as prominent as in other arid areas.