Quantitative analysis method for isocyanato in melamine tail gas

Abstract

The invention relates to melamine tail gas analysis, in particular to a quantitative analysis method for isocyanato in melamine tail gas. The quantitative analysis method comprises the following steps of: S1, carrying out sampling; S2, carrying out pipetting; S3, accurately transferring 50.0 ml of a to-be-detected sample into an iodine flask, adding 20 ml of an analytically pure formaldehyde solution, dropwise adding a plurality of drops of a phenolphthalein indicator, and neutralizing with a 1.0 mol / L NaOH standard solution until the solution is light red; S4, heating the iodine flask on an electric furnace until boiling for 1 minute; S5, plugging, cooling to room temperature, not forming negative pressure in the flask, adding 5mL of a di-n-butylamine toluene solution into the iodine flask by using a transfer pipette, and leaching the wall of the iodine flask by using 10ml of toluene; S6, adding 50 ml of acetone into a measuring cylinder, and subjecting the mixture to a standing reaction for 15 min at the room temperature; S7, titrating excessive di-n-butylamine by using a potentiometric titration method or a chromogenic titration method; and S8, calculating the content of isocyanato according to a titration result in S7. The new quantitative analysis method for isocyanato is provided through design, operation is easy, the result is accurate, and the method has popularization significance.

Description

technical field [0001] The invention relates to the analysis of melamine tail gas, in particular to a quantitative analysis method for isocyanate in melamine tail gas. Background technique [0002] There is a large amount of ammonia in the tail gas of melamine. During the titration of isocyanic acid and its esters, ammonia reacts with hydrochloric acid to form ammonium chloride. Therefore, when titrating isocyanic acid and its lipids, ammonia and its esters must be removed in advance. Salt substances, but in the current prior art, there is no effective solution to solve the above technical problems. Contents of the invention [0003] In order to solve the problems in the background technology, the invention provides a kind of quantitative analysis method of isocyanate in melamine tail gas, by proposing a kind of new quantitative analysis method, make the quantitative analysis of isocyanate in melamine tail gas more accurate, the present invention The technical scheme adop...

AI Technical Summary

Problems solved by technology

[0002] There is a large amount of ammonia in the melamine tail gas. During the titration of isocyanic acid and its esters, ammonia reacts with hydrochloric acid to form ammonium chloride. Therefore, when titrating isocyanic acid and its lipids, ammonia and its esters must be removed in advance Salt substances, but in the current prior art, there is no effective solution to solve the above technical problems

Images