Method for detecting content of free amine in NMP

Abstract

The invention relates to a method for detecting content of free amine in NMP. The method comprises the following steps: 1) carrying out material preparation; 2) preparing an indicator solution; 3) placing a conical flask on an electronic balance, carrying out peeling, measuring 50mL NMP with a measuring cylinder and pouring the measured NMP into the conical flask to accurately obtain the mass, recorded as m, of the NMP; 4) adding 50mL absolute ethyl alcohol and 3-4 drops of bromocresol green-methyl red indicators into the conical flask in sequence and then, smoothly shaking the conical flask to make the mixture uniform; 5) carrying out titration with a 0. 01mol / L hydrochloric acid standard solution till the solution is turned from green to light yellow and keeping for 30s till the color does not fade, and recording the consumption volume V of the hydrochloric acid standard solution; 6) carrying out blank test and recording consumption volume V0 of the hydrochloric acid standard solution; and 7) carrying out calculation. The method for detecting the content of free amine in the NMP adopts the absolute ethyl alcohol as a diluent instead of isopropanol adopted as the diluent in the previous method; and compared with other diluents, the absolute ethyl alcohol has the advantages of safety, environmental protection, low toxicity, stable chemical properties, not easy oxidation and lowcost and the like, and is a good diluent for detection of the free amine in the NMP.

Description

technical field [0001] The invention belongs to the technical field of chemical detection and relates to the detection of raw materials in the lithium battery industry, in particular to a detection method for free amine content in NMP. Background technique [0002] At present, the national policy support for the new energy industry is developing rapidly, and the development of new energy batteries as the core is also advancing by leaps and bounds. Regardless of whether PVDF is used as a binder or the main material of the negative electrode, graphite and conductive agent, the raw material NMP (N-methyl The role of pyrrolidone) in the middle can effectively dissolve PVDF to make it have better adhesion. Adding a small amount of NMP to the graphite material can also improve the wettability of graphite, making it better mixed with the binder, and finally improving The quality of the battery. [0003] However, due to its production process, NMP contains a small amount of free am...

AI Technical Summary

Problems solved by technology

[0003] However, due to its production process, NMP contains a small amount of free amine as a raw material, but it is an impurity in the finished product. If the content is too high, it will affect the quality of lithium batteries and cause problems such as battery self-discharge.

At present, there is no effective and fast detection method for the detection of free amines in NMP, and it is impossible to accurately evaluate the performance of NMP.

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