The kinetics of the slow oxidation of CO in the presence of Hz have been studied above the second explosion limit for the mixture 2CO + 0 2 + X% Hz a t the temperature range of 53O-57O0C, pressures from 300 to 530 torr, and hydrogen contents of 1.1,2.8, and 5.7%. The second explosion limit has been experimentally determined for the mixture of 2CO + 0 2 containing 1.0,3.0, and 5.7% Hz. On the basis of the oxidation scheme of CO in the presence of Hz, which includes the accepted mechanism of oxidation of hydrogen supplemented by the reactions in which CO takes part, the second explosion limit and the profiles of the slow reaction are calculated by computer methods. The agreement found between experimental and calculated values allows one to conclude that the scheme under consideration rather completely described the slow reaction above the second limit and the occurrence of the second explosion limit in the mixture CO-02-Hz. The rate constant for the reaction HOy + CO -OH + COz was calculated from the experimental data and was found to agree with previous determinations.

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One of the main problems of nature conservation and protection of the environ-ment is the reducing of flammability of natural and synthetic materials as well as products based on them. In order to obtain non-combustible materials such as flame retardants, monosodium salt of orthophosphoric acid, urea, thiourea and their mono-methylol derivatives, as well as N-monomethylol acrylamide were used in this work. The reaction for the synthesis of the mentioned compounds was carried out in the presence of a small amount of water. During the reaction between urea and monosodium salt of orthophosphoric acid, ammonia and СО2 were released. In the case of the reaction of thiocarbamide with the monosodium salt of orthophosphoric acid, in addition to ammonia and CO2, hydrogen sulfide is partially released, the formation mechanism of which is presented in the work.

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The reaction between urea and melamine was studied. The reaction resulted in tris-carbamide derivative of melamine. During the reaction between the melamine derivative and the glycoside group of chitosan the sim-triazine functional groups were formed, which are included in the structure of synthesized derivative of chitosan. The synthesized derivative of chitosan was tested. It is recommended to use this chitosan derivative as an absorbent for the separation of heavy metal ions such as Cd2+, Hg1+, Hg2+, Co2+, Ag1+, As3+, As5+, etc. from the aqueous solutions of salts.