MOSCOW, June 13. /TASS/. Scientists from National Research University "Belgorod State University" (BelSU) have patented a method of producing a base for synthetic detergents with increased biodegradability, the university's press service told TASS on Tuesday.

"The new active base, developed within the framework of the world-class scientific and research center "Innovative Solutions in the Agroindustrial Complex", can be used to produce household and technical detergents with a high degree of full biodegradability, which will significantly improve the ecology," the press release said.

"Linear" sodium alkylbenzene sulfonates (LSAS) with an alkyl group containing 10-14 carbon atoms have been produced worldwide for more than 70 years and are still one of the most common active bases of synthetic detergents. More than 3 million tons of LSAS are produced in the world annually. Now the most widely used (80% of the total volume) is the "Pacol-detergent" process, a technology developed back in the 1960s by the UOP company. Its peculiarity is that the base obtained by alkylation of benzene with C10-C14 olefins contains more than 25 branched homologues (substances of similar structure) of LSAS. This is one of the main reasons for the poor biodegradability of the complex mixture. Moreover, the biodegradability of LSAS depends on the type of alkylation catalyst used: aluminum chloride (AlCl3) or hydrogen fluoride (HF). However today indicators of LSAS biodegradability of approximately 80% cannot be considered sufficient, because even after going through biological treatment plants, almost one fifth of these substances remain in waste water, contaminating water bodies.

Researchers of the Institute of Pharmacy, Chemistry and Biology of BelSU under the guidance of Professor of General Chemistry Department, Doctor of Biological Sciences Viktor Bocharov faced the task of improving the method of obtaining LSAS using the "Pacol-detergent" technology, which will allow getting an active base with a higher degree of full biodegradability.

As a new solution, BelSU proposed the method of synthetic detergents base production (LSAS) which implies alkylation of benzene with internal olefins in the presence of hydrogen fluoride, followed by sulfation of alkylbenzenes with sulfur gas (SO3) and neutralization of obtained alkylbenzenesulfonic acids with alkali. The novelty of the approach consists in using a certain mass ratio of elements of the mixture of "linear" alkylbenzenes.

"As a result of the conducted research, BelSU scientists managed to propose a method of obtaining a base for synthetic detergents with a number of advantages compared with existing analogues. The patented method produces an active base which is able to pass the process of activated sludge adaptation faster - in three to four days. After that, it is fully biodegraded by the active sludge up to 95%, which is almost one and a half times larger than the indicator of the earlier prototype. In the proposed method, some of the "linear" sodium alkylbenzene sulfonates included in the base are able to biodegrade to more than 99%. The amount of slippage of lower homologues - not adsorbed by sludge and not decomposing water pollutants - is reduced by 15-20% compared to analogues and will be less than 5%," the press-service said.