FORENSIC INVESTIGATION OF OXYGENATES IN MOTOR TYPES OF GASOLINE
Authors: Sych Oleh , Kornienko Andrii , Yevtushenko Nadiia 
Published: August 2022

The main types of oxygenates, which are used in the manufacture of motor types of gasoline, are considered. Oxygenates (oxygen-containing compounds) is the general name for lower alcohols and ethers used as high-octane components of motor fuels. For the manufacture of motor types of gasoline, a low-octane base is used to which high-octane components are added. In many cases, lower alcohols (methanol, ethanol, etc.) and ethers (methyl tert-butyl ether, tert-amyl methyl ether, etc.) are used as high-octane components of motor types of gasoline. Straight-run gasoline and stable gasoline are often used as the low-octane gasoline base for mixed motor types of gasoline.

Methanol (CH3OH) is the simplest monohydric alcohol. Methyl alcohol is now produced synthetically from carbon monoxide (CO) and hydrogen (H2). Ethanol (ethyl alcohol) is a representative of monohydric alcohols with the formula C2H5OH. The production of ethyl alcohol is possible in several ways: biochemical, hydrolysis, synthetic, or ethylene hydration. For the manufacture of motor types of gasoline, dehydrated ethyl alcohol (bioethanol, an alternative universal component of motor fuel (KMPU), etc.) is used.

Bioethanol is produced according to DSTU 7166: 2010 “Bioethanol. Technical mind”. According to DSTU 7166: 2010, bioethanol is dehydrated ethyl alcohol made from biomass or from raw ethyl alcohol for use as biofuel. As a technological and denaturing additive, gasoline (petroleum products) is introduced into bioethanol in an amount of up to 1.5 % by volume.

KMPU is produced in accordance with TU U 20.5-00372536-001: 2013 “Component of firing motor alternative universal (KMPU). Technical conditions”. An alternative universal motor fuel component is dehydrated ethyl alcohol with a complex of additives, which is used for the manufacture of mixed motor types of gasoline and alternative types of motor types of gasoline. Compositionally, KMPU is similar to bioethanol but differs from it in the presence of another high-octane component – methyl tert-butyl ether (MTBE).

Methyl tert-butyl ether, formula CH3-O-C (CH3)3 is a product that can be obtained in large quantities by reacting isobutylene with methanol. The advantage of MTBE is its good solubility in gasoline, and, at the same time, it is not washed out of it with water. MTBE does not impair the physical and chemical stability of gasoline; it is characterized by stable anti-knock properties during storage and operation.

The article discusses the results of the study of the listed oxygenates by gasliquid chromatography. This method makes it possible to establish the qualitative and quantitative composition of oxygenates and motor types of gasoline based on them.
It is shown that from readily available petroleum components (stable gas gasoline) without the use of complex technological equipment by mixing with oxygenates, it is possible to obtain a gasoline mixture with a high detonation resistance, which is fake gasoline in composition.

When mixing in certain proportions a low-octane gasoline base, for example, stable gas gasoline and oxygenates (lower alcohols, ethers), which have appropriate performance characteristics, it is possible to obtain commercial gasoline that will meet the requirements of regulatory documents (DSTU) for motor types of gasoline.

The considered technology also allows, when mixing in the calculated proportions of commercial gasoline A-92 (A-95) with oxygenates and stable gasoline, to improve the operational characteristics (knock resistance) of the obtained gasoline mixture or to increase the volume of the resulting gasoline mixture without improving its operational characteristics.

Key words: blended types of gasoline, alternative types of gasoline, oxygenates, lower alcohols, ethers, bioethanol, alternative motor fuel component universal.