SYNTHESIS OF COPOLYMERS BASED ON DODECYL METACRYLATE AND STYRENE AND INVESTIGATION OF THEIR EFFECT ON LOW-TEMPERATURE AND PHYSICO-CHEMICAL PROPERTIES OF DIESEL FUEL

ABSTRACT

The article is devoted to the synthesis of copolymers based on dodecyl methacrylate and styrene. Various external influences (molar ratios of monomers, temperature, and initiator) on the copolymerization reaction have been studied. The effect of the molar ratio of monomers in the synthesized copolymers on the low-temperature and physicochemical properties of diesel fuel has been studied. The depressant properties of diesel fuel of copolymers obtained by this method have been studied. The 9:1 ratio of DDMA to styrene-based polymer improved the low temperature properties of diesel fuel.

АННОТАЦИЯ

Статья посвящена синтезу сополимеров на основе додецилметакрилата и стирола. Исследованы различные внешние воздействия (мольные соотношения мономеров, температура и инициатор) на реакцию сополимеризации. Исследовано влияние мольного соотношения мономеров в синтезированных сополимерах на низкотемпературные и физико-химические свойства дизельного топлива. Изучены депрессорные свойства дизельного топлива сополимеров, полученных этим способом. Соотношение ДДМА и полимера на основе стирола 9:1 улучшило низкотемпературные свойства дизельного топлива.

Keywords: winter diesel fuel, hydrotreated diesel fuel, limiting filtration temperature, pour point depressant, dodecyl methacrylate, higher fatty alcohols, styrene.

Ключевые слова.: зимнее дизельное топливо, гидроочищенное дизельное топливо, предельная температура фильтрации, депрессорная присадка, додецилметакрилат, высшие жирные спирты, стирол.

Introduction

Rational use of fuel and lubricants, improvement of their quality and expansion of resources are the main tasks of modern oil refining and petrochemical industry. It is known that special attention is being paid to the reduction of toxic exhaust gases released into the atmosphere from vehicles, boilers and thermal power plants, industrial enterprises, that is, all objects that use oil products, which contribute a lot to atmospheric air pollution. Currently, an important solution to this problem is to strengthen the requirements for the quality indicators of commodity oil products. In the modern economy, one of the urgent problems is to constantly increase production efficiency along with improving product quality and environmental safety. [1]

In the production of diesel fuel at oil refineries, in addition to operational characteristics, special attention is paid to improving environmental indicators. The most important operational characteristics of internal combustion engines are reliability, fuel efficiency and environmental safety indicators, which depend on a set of design and operational factors, while fuel quality is one of the most important factors. The physical and chemical properties of fuel affect the processes of mixture formation and combustion in diesel cylinders, complete combustion of fuel, fuel efficiency, the content of harmful substances in engine exhaust gases, the resource of fuel supply equipment and diesel fuel. is to provide the desired features.[2]

With the help of additives, it is possible to reduce fuel consumption in engines, increase the completeness of their combustion, reduce the smoke of exhaust gases and a number of other important problems of the production and use of fuels, non-freezing of fuel in cold conditions and complex complex problems can be successfully solved.

Currently, according to the chemical nature of diesel fuel, depressors can be classified as follows:

• ethylene copolymers with polyethylene macromolecules or polar monomers containing a polar functional group (ethylene-vinyl acetate copolymers and their compositions, copolymers of ethylene with various polar monomers) [3];
• polyacrylates, polyalkyl methacrylate polyalkyl(meth)acrylates, copolymers of alkyl(meth)acrylates; [4];
• macromolecular ethylene-propylene, ethylene-propylene-diene and their decomposition products, copolymers of α-olefins, modified polyolefins [5];
• macromolecular poly-2,5-furandiones [6];
• fumaric acid and vinylacetate macromolecular copolymers [7].
• arene polymers consisting of two or three monomers;
• non-polymeric chemicals (alkylnaphthalenes; polyhydric alcohols and complex esters of higher fatty acids [8].

It is known that the hydrocarbons that affect the low-temperature properties of diesel fuel are n-alkanes of a simple structure with a large number of carbon atoms in the chain. To improve the low-temperature properties of diesel fractions, reducing n-paraffin concentration or depressor-dispersing additives are used. The inclusion of depressors in the composition of DYo allows to increase the range of its use in cold climates of the environment.

Materials and methods

Copolymerization reactions of dodecyl methacrylate and styrene. To determine the dynamics of the change in the composition of the copolymers, the copolymerization of the investigated monomers was deaerated at a temperature of 60-85 ⁰C in a three-mouthed flask equipped with a thermometer. The total concentration of monomers in the solution was changed from 0.1 to 0.9 mmol/g. The concentration of the initiator (AIBN) was from 0.50 to 0.80 % mol. Toluene was used as a solvent. Based on these results, the average composition of copolymers obtained at different conversions of comonomers was calculated. Upon reaching a certain conversion of monomers to copolymerization (in the range of 15-45%), the obtained reaction mass was diluted with benzene and the resulting copolymer was precipitated in isopropyl alcohol. Then the copolymers were dried in a vacuum (20-30 ⁰С) to a constant mass. The copolymerization reaction can be explained as follows.[9]

Figure 1.Copolymer formation reaction

The molar ratio of monomers to the copolymerization yield and molecular mass, and temperature were studied and presented in the figures below. When the temperature is 60-85 ^oC, the amount of styrene and initiator per unit of copolymer was studied when the ratio of dodecyl methacrylate and styrene monomers was 9:1.

In pictures 2 and 3, when the amount of styrene in the copolymerization reaction is 5-20% and the initiator is 0.50-0.80%, when the temperature increases to 60-75 ^oC, the copolymer yield increases from 75 ^oC to 85 ^oC and the initiator is 0.70% we can see that the yield of the reaction decreases when In this case, the increase in temperature is explained by the fact that it accelerates the chain growth reaction in the formation of all polymerization and copolymerization reactions.

It can be seen from the pictures 4 and 5 below that the temperature change from 60oC to 80oC increases the amount of styrene in the initial mixture of monomers in the copolymer from 5 to 20% and the amount of the initiator increases by 0.50-0.70%, the molecular mass of the copolymer increases from 6000 to 8000. temperature 80 ^oC and 0.70% increase of the initiator led to a decrease in the molecular weight of the copolymer from 8000. This is explained by the high reaction activity of styrene and polydispersity of the molecular mass of the copolymer.

Therefore, it is possible to control the yield and molecular mass of the synthesized copolymer by changing the molar amount of dodecyl methacrylate and styrene monomers in the initial mixture of the copolymerization reaction, the temperature and the amount of the initiator.

The copolymer structure was investigated based on IR-Shimadzu IRAffinity-1S spectroscopic research methods. As a result of comparison of the IR spectra of DDMA-ST copolymer, it is possible to clearly see the absorption frequencies characteristic of the fragments in its composition in the IR spectrum of the copolymer.

Figure 6. IR spectrum of dodecyl methacrylate and styrene copolymer

It was proved that a copolymer was formed on the basis of dodecyl methacrylate and styrene. In the spectra, the absorption region of 698.23-765.74 cm^-1 is the sp³ hybridized alkyl group CH₂ vibrational vibration, 877.91-1022.27 cm^-1 benzene ring, 1242.26 cm^-1 is the valence vibration frequency of complex ether group, has a very strong intensity. 1739.79 cm^-1 of carbonyl group and 3000.00 cm^-1 of sp³ hybridized CH₃-C- belong to valence vibrations. [10]

The effect of the synthesized copolymer on the low-temperature properties of diesel fuel was studied and the results are presented in Table 1.

Table 1.

Effect of additives based on dodecyl methacrylate and styrene on low temperature properties of diesel fuel

Conclusion

It was proved that the reaction yield and molecular mass can be controlled by changing the effect of temperature and the amount of initiator when dodecyl methacrylate and styrene monomers are 9:1 on the copolymerization reaction, and it is proved that it belongs to the functional groups of the copolymer using IR spectroscopy. Synthesized additives exhibit depressor properties in diesel fuel, and the amount of 0.30% did not change the clouding temperature, it was achieved that the filtration threshold temperature was reduced to -19 ^oC and the solidification temperature to -28 oC.

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