This apparatus allows for obtaining the IR spectrum of the sample in the wave number range of 800-4000 cm−1. High temperature of 2,6-DMP synthesis and high product concentration in the exhaust gases resulted in the necessity of diluting post-reaction gases in two-steps with inert gases, by simultaneous cooling down to about 160°C, prior to introduction of the gaseous products into the analyzer. Such diluted mixture containing all the products of the reaction was passed through the demister, reheated to 180°C and directed to the gaseous cuvette of FTIR analyzer after filtration on ceramic and Teflon filters.