Monday, August 25, 2014

Xylene Migration And Transformation

Xylene is mainly used in chemical industry. The industries who use xylene more are organic solvents and synthetic medicine. Such as paint, resins, dyes, detergents, detergent, pesticide, dynamite and so on. Xylene is also one of the components for aviation fuel.

Xylene can discharged into water bodies with the industrial wastewater in the process of industrial production. But there is no persistent pollution to water because that the xylene has strong fugacity in the water.

Generally speaking xylene will degrade in the environment. Xylene transfer speed is slower than the volatile speed in aqueous solution. The xylene will also be photolysis after volatile into the air. The photolysis process is the main migration and transformation process. The xylene harm is not badly than we imagine. The xylene incoming and metabolism to human body is very fast. However the xylene in the human body could excreted totally if it stop to contact with xylene in 18 hours. At the same time, it has no effect on human health. So not contacting or incoming the xylene will not affect human health unduly. Xylene is belong to moderate flammable items and xylene vapor is heavier than the air. So xylene often close to the ground and spread along the ground when burning.

Monday, August 11, 2014

Production Technology In Aniline Industry

Aniline is regarded as an organic intermediates. It is widely used in synthetic materials, rubber additives,dyes,pigments,pharmaceuticals and other organic chemical products. Recent years, with the demand of global polyurethane raw material MDI growth, it has become the main consumer areas of aniline. According to statistics, global aniline capacity has been reached 3.773 million t/a in 2004, annual output is 2.315 million tons and the apparent consumption was 2.24 million tons.

Aniline industry has began in 1857. Aniline industry adopt nitrobenzene iron reduction method. This method needs big equipment and also in serious corrosion, big iron consumption, serious pollution. Catalytic hydrogenation of nitrobenzene method instead of it until 1950s. At present, this method has accounted for 85% of the total capacity of aniline. Phenol ammoniation is occupied about 10% and iron powder reduction method is occupied about 5%.

Nitrobenzene iron reduction method is using intermittent production and reduction nitrobenzene into aniline through hydrochloric acid medium under about 100 ℃. There are many devices adopt this method in China because that method can  byproduct of iron oxide pigments. The rapid development of MDI and other downstream products brought hitherto unknown opportunities to the development of aniline industry. The experts recommended that small and medium sized enterprises must develop Adiabatic Nitration Technology with independent intellectual property rights, reduce energy consumption and cost in order to improve China’s aniline industry competitiveness in the international market.