Sulfur nanoparticles were prepared in liquid phase at normal pressure and room temperature. Sulfur powder was applied as original material, formic acid as precipitating agent, and polyethylene glycol-400 (PEG-400) as dispersing agent. The synthesis conditions of sulfur nanoparticles were optimized and analyzed, and its dispersion in organic solvent was studied. The particle size and crystalline structure of sulfur nanoparticles were characterized by laser size analysis device (LSA), transmission electron microscope (TEM) and X-ray diffractometer (XRD). The results show that monoclinic sulfur nanoparticles was successfully synthesized by liquid phase precipitation method. The sulfur nanoparticles are in sphere shape, and the average particle size is 50～80 nm. This method is a novel approach to produce nanosized sulfur particles, which could be applied to prepare sulfur nanoparticles in medicine and chemical industry.

Key words: sulfur, nanoparticle, synthesis in liquid phase, dispersing agent, dispersion