http://www.google.sn/patents/CN1634884A?cl=en

NMP in Germany, was designated as the three toxic chemicals into the atmosphere to allow the concentration of 100ppm. China is currently no provision, but if direct emissions, their atmospheric concentrations much higher than the required standards abroad, is a potential source of pollution. NMP into the atmosphere, but also caused a lot of waste of raw materials, only in China more than 60 lithium-ion battery plant, currently all use imported NMP, with a total of about 2,000 tons, valued at 60 million yuan. With the increase of the national production capacity of lithium-ion batteries, the use of NMP annual consumption will reach 4800 tons, the need to consume about 144 million yuan RMB. Therefore, not only is the economic cost recovery NMP problem, but is a green issue, the development of new technology related to the recovery of NMP significant economic and environmental benefits.