The method of identifying maleic anhydride and CIS acid was as follows

1.称量相同的重量，将其溶于水，然后用碱滴定。 酸是更多的碱，酸是更少。

1. Weigh the same weight, dissolve it in water, and titrate with alkali. Acids are more bases and less acids.

2，或取少量等量的样品溶于水，用pH计检测，较低的pH是酸酐，较高的pH是酸。

2, or take a small amount of the same amount of sample dissolved in water, detected by pH meter, lower pH is anhydride, higher pH is acid.

顺丁烯二酸酐

Maleic anhydride

3.也可以通过熔点检测，酸酐和酸的熔点不同。 马来酸酐为约52〜53℃，且酸为约130℃。

3. The melting point of anhydride and acid is different. Maleic anhydride is about 52-53 ℃, and acid is about 130 ℃.

4，简单的方法，找到一小块不锈钢，将两个样品稍微放在钢板的两边，用打火机加热两个样品之间，液化和挥发的是马来酸酐。

4. Simple method: find a small piece of stainless steel, put two samples slightly on both sides of the steel plate, and heat the two samples with a lighter. The first thing to liquefy and volatilize is maleic anhydride.