1-Methylimidazole is a highly important fine chemical raw material and intermediate with a wide range of applications. It is primarily used as an organic synthesis intermediate, such as in ionic liquids, resin curing agents, and adhesives. It is also an effective ingredient in many pesticides, enzyme inhibitors, pharmaceuticals, and fine chemicals. In the synthesis of 1-Methylimidazole, rapid and accurate detection of the product content in the aqueous synthesis solution is crucial for yield control.
A method for detecting the content of 1-Methylimidazole in aqueous systems includes the following steps:
S1. Quantitative method: The internal standard method is used, with ethylene glycol as the internal standard and N,N-dimethylformamide as the solvent for the sample dissolution.
S2. Construction of a calibration curve: Different ratios of ethylene glycol and pure 1-Methylimidazole mixed solutions are prepared. They are then diluted to 50ml with N,N-dimethylformamide, and an injection volume of 0.4μl is used. The peak areas of ethylene glycol and pure 1-Methylimidazole are determined using gas chromatography to obtain the peak area ratio at different mass ratios. A calibration curve is plotted to obtain the correction factor.
S3. Detection of the test sample: Accurately weigh 1.8000-2.2000g of the test sample in a 50ml volumetric flask, then add 0.5500-0.6500g of ethylene glycol and make up to volume with N,N-dimethylformamide. An injection volume of 0.4μl is used. The peak area ratio of the internal standard and the sample is calculated from the chromatogram obtained from the gas chromatograph. The content is calculated using the correction factor obtained from step S2. The sample is injected three times, and the average value is taken.
[1] [Chinese Patent] CN202010622287.7 A method for detecting the content of 1-Methylimidazole in aqueous systems.