QUANTITATIVE-ANALYSIS OF N-METHYL-2-PYRROLIDINONE IN COAL EXTRACTS BY TGA-FTIR

N-Methyl-2-pyrrolidinone (NMP) is widely used in coal extraction. It has been shown that NMP is strongly retained in coal extracts and the retained NMP affects the character of the extracts. In order to calculate the actual extraction yield and understand the interaction between NMP and coal, the amount of NMP retained by its coal extracts must be quantified. TGA-FTIR has been applied to the quantitative analysis of NMP. Neutral aluminum oxide with 4.74% NMP added was used as a standard, and a linear calibration curve for the area of the NMP profile and the retained NMP weight was obtained. Several NMP-soluble coal extracts were tested by this method. The percentage of the NMP retained by these extracts varied from 1.08 to 3.40% with deviations (n = 2) within 0.25%. The detection limit can be as low as 5 mug with a S/N of 5 when the C=O stretching band of NMP is used.