In 1911, he left the university with a group of scientists in protest against the policy of the tsarist Minister of Education Lev Kasso.

Under the leadership of Zelinsky, the process of catalytic cracking of oil was studied in detail with the determination of the chemical nature of its products by spectral methods.

Zelinsky also supervised work on finding ways to rationally use the products of primary processing of solid fuels - coal, shale and peat.

During the war years Zelinsky found a solution to this problem by passing shale oils mixed with hydrogen over platinum or nickel on aluminum oxide at 300 °.

The development of petrochemistry in the USSR has led to a radical reconstruction of the oil refining industry for the production of artificial liquid fuel.

[6] Zelinsky's scientific activity was very versatile: his works on the chemistry of thiophene and the stereochemistry of organic dibasic acids are widely known.

Subsequent research led Zelinsky and his students to the discovery of the reaction of hydrogenolysis of cyclopentane hydrocarbons with their transformation into alkanes in the presence of platinized coal and excess hydrogen in 1934.

In 1915, Zelinsky successfully used oxide catalysts for oil cracking, which led to a decrease in the process temperature and an increase in the yield of aromatic hydrocarbons.

In 1918–1919, he developed a method for producing gasoline by solar oil and petroleum cracking in the presence of aluminum chloride and aluminum bromide; the implementation of this method on an industrial scale played an important role in providing gasoline to the Soviet state.

Zelinsky improved the reaction of catalytic conversion of acetylene into benzene by suggesting the use of activated carbon as a catalyst.

The works of Zelinsky and his scientific team on the adsorption of gases on activated carbons were important for the country's defense ability, the creation of a coal gas mask in cooperation with Kumant (1915) and its adoption during the First World War in the Russian and allied armies were significant for the country's defense ability.

[7][8] Zelinsky created a large scientific school and its scientists made fundamental contributions to various fields of chemistry.

A. Kazansky, K. A. Kocheshkov, S. S. Nametkin, A. N. Nesmeyanov; Corresponding Members of the Academy of Sciences of the USSR N. A. Izgaryshev, K. P. Lavrovsky, Yu.

G. Mamedaliev, B. M. Mikhailov, A. V. Rakovsky, V. V. Chelintsev, N. I. Shuikin; professors V. V. Longinov, A. E. Uspensky, L. A. Chugaev, N. A. Shilov, V. A. Nekrasova-Popova and others.