The characteristics and research development of AlN powder synthesis methods including direct nitridation, carbothermal reduction, self propagation high temperature synthesis, vapor phase reaction and plasma method were reviewed in the paper.

In this paper, Si3N4 complex-phase powders were prepared by direct nitridation by means of doping, controlling the preparation conditions and altering the way of mixing raw materials.

Preparation of silicon nitride powder by a direct nitridation process based on fluidization technology;

8μm as raw materials, and adding silicon nitride as diluents, silicon nitride powders were prepared via direct nitridation process of silicon powders at atmospheric pressure and high temperature.

Currently, the direct nitridation of silicon is the most prevalentpreparation method of silicon nitride.

Five long-chain saturated alkanoyl-6O-D-isoascorbates(alkanoyl=decanoyl,lauroyl,myristoyl,palmitoyl and stearoyl) were synthesized by esterification(or transesterification) of D-isoascorbic acid with alkanoic acids using concentrated H_2SO_4 as a medium and a catalyst at room temperature.

There are two methods for synthesis of the fluoroporphyrins: direct and indirect fluorination.