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ISSN 2522-1841 (Online) AZERBAIJAN CHEMICAL JOURNAL № 1 2023 ISSN 0005-2531 (Print)
UDC 665.7.038
MODIFIED POLYALKENYL SUCCINIMIDE ADDITIVE FOR MOTOR OILS
J.Sh.Hamidova, E.U.Isakov, E.I.Hasanova, N.J.Huseynova
A.Guliyev Institute of Chemistry of Additives, Ministry of Science and Education of the
Republic of Azerbaijan
c.hamidova@mail.ru
Received 20.04.2022 Accepted 24.08.2022
The article is devoted to the synthesis of a chemically modified version of one of the most important additives for the prevention of low-temperature precipitation in engine oils - polyalkenyl succinimide. This additive is prepared by alkylating maleic anhydride with an a-olefin oligomer and then reacting the resulting oligoalkenyl succinic anhydride with various amines. A new compound, an oligomer of hexene-1 with di-cyclopentadiene, was used as an alkylating agent, which makes it possible to expand the raw material reserves of oligomeric compounds used in the synthesis of polymer additives, as well as to impart anticorro-sive properties to the additive by introducing dicyclopentadiene rings. The composition and structure of the obtained compounds were studied by appropriate physicochemical research methods. The content of 1.5% of the obtained additive in M-11 oil completely eliminates oil corrosion and improves detergent properties. And this allows you to create a lubricant composition with a simpler composition and, as a result, gives an economic effect. The sample of the new additive complies with the requirements for the industrially produced C-5A additive and, in addition to an increased oil viscosity index; it also has anti-corrosion properties, which is due to the chemical structure of the raw material, i.e., the presence of a carbocyclic dicyclopentadiene fragment in the molecule.
Keywords: additives, succinimides, maleic anhydride, hexene-1, dicyclopentadiene, alkenyl succinic anhydride, diethylenetriamine, succinimide additives.
doi.org/10.32737/0005-2531-2023-1-149-154 Introduction
During the operation of engines, due to the influence of high temperatures and loads, chemical processes of oxidation, destruction and condensation occur in oils; there is an accumulation of undesirable products that worsen their operational properties. Products of incomplete combustion of fuel (soot, hydroxy acids, products of deeper transformations) and oil oxidation (resins, asphaltenes, carbon particles, etc.), which can form up to 10% by weight during the operation of loaded diesel engines, settle in the form of coke-like deposits on the pistons and pasty deposits in the crankcase.
Expansion and deepening of research on the development of new highly destructive polymer compounds and the identification of the possibility of using them as viscosity-multifunctional additives is a very urgent problem.
A simpler and more reliable way to increase the destructive stability of viscous additives is the chemical modification of their struc-
ture, i.e. sopolymerization of the main monomer with an insignificant amount of stabilizing como-nomer, for which vinyl aromatic compounds are used (the stabilizing effect of aromatic hydrocarbons is transferred through the side chain, and the nature of the main chain does not change) [1, 2].
In order to expand the raw material resources of stabilizing monomers used in copo-lymerization with vinyl monomers, with a change in the nature of the main polymer chain, copo-lymerization was carried out with carbocyclic monomers - namely, with dicyclopentadiene.
Dicyclopentadiene is an available industrial product of coal origin. It is obtained from petrochemical raw materials - by pyrolysis of straight-run gasoline. The purpose of the process is to obtain ethylene. This forms the hydrocarbon fraction C5, which contains 10-25% cyclopentadiene, which turns into dicyclopentadiene upon standing. Ethylene plants can produce 2.0-6.0 thousand tons/year of cyclopentadiene [2].
Among the ashless dispersants, oligoalken-ylsuccinimides (succinimide is called imide of
succinic acid (HOOC-CH2-CH2-COOH)) occupy the main place. The process of obtaining them consists of two stages: the preparation of alkenyl-succinic anhydrides by the condensation of oli-goolefins with maleic anhydride and the formation of succinimides by the interaction of the obtained anhydrides with various amines. An important feature of such compounds, unlike other types of detergent-dispersant additives, is their ability not only to neutralize acidic contaminants, but also to prevent the formation of low-temperature sludge.
As is known, detergent-dispersant additives have the ability to disperse oil-insoluble particles formed as a result of the engine's working process. As a result, these particles are held in suspension in the oil and do not settle on the surface of metal parts.
In combination with other additives, suc-cinimides, which are ashless dispersants, can increase the life of oils in carburetor and diesel engines by 1.5-2.5 times, compared with oils containing only ash detergent additives. Currently, their production exceeds 20% of the total production of additives.
In this work, in order to identify new effective properties, a multifunctional additive of the succinimide type was synthesized and investigated, for which a low molecular weight co-oligomer of hexene-1 with dicyclopentadiene was
used as a starting material in the synthesis [3-9].
In view of the fact that the succinimide additive is the only additive that eliminates the formation of low-temperature deposits in engine oils and has a multifunctional - detergent-dispersing action, the synthesis of this additive is of certain interest. A succinimide additive obtained on the basis of co-oligomers with dicy-clopentadiene units provides the synthesized compound with additional anticorrosive properties, which makes it possible to develop a lubricant composition of a simpler composition.
Experimental part
Double copolymerization of hexene-1 with dicyclopentadiene is carried out by the method of ionic polymerization in the presence of an aluminum chloride catalyst [10]. When co-oligomerization was carried out in the temperature range of 10-200C, the molecular weight of the resulting product was 800-1200. In the initial mixture of monomers, the content of dicyclopentadiene is 10-20%, and in the composition of the co-oligomer of dicyclopen-tadiene units - 7-15%. The composition of co-oligomers was established based on the determination of unsaturation (by the method of bromine numbers) and elemental analysis. Co-oligomerization can be schematically represented as follows:
CH2 — CH - CH9 - CH9 - CH9 - CH
*2
2 '
2
+
kat
—»-----CH2 - CH
C4H9
Dicyclopentadiene has two unsaturated bonds and upon opening of one of them, during co-oligomerization, the other one remains unchanged, i.e. simultaneous opening of double bonds is not observed. As a result, the resulting products are unsaturated; no compound with cross linked and branched structures is formed, since
co-oligomers are readily soluble in common hydrocarbon solvents and in petroleum oils.
The synthesized co-oligomer with a molecular weight of 1000 with a dicyclopentadiene unit content of 10% was used as a starting material in the synthesis of a polyalkenyl succin-imide additive.
The synthesized co-oligomer of molecular weight 1000 with a content of dicyclopenta-dine units of 10% was used as a feedstock in the synthesis of a polyalkenylsuccinimide additive, the first stage of which is condensation.
It has been established that the condensation reaction of maleic anhydride with a-olefins of normal structure proceeds according to the molecular mechanism, accompanied by a syn-
chronous electronic transition, without the formation of intermediate ions or radicals. The formation of a transition complex is accompanied by a decrease in the free energy of the system due to the delocalization of the electron density. During the condensation reaction of maleic anhydride with a-olefins of normal structure, two C-C n-bonds and one C-H o-bond are broken [11]:
Rn M CH
CH
X
CH,
CH - co
+
>°
CH - co
Rn .HN
\X \
CH
CH-CO
Ii f >°
CH ,CH - CO
\/
CH2 -
R - CH = CH - CH2 - CH - CO n I
CH-CO
Raising the temperature above 2200C is not advisable, as the color of the reaction product darkens, solid sediments are obtained as destructive reactions take place, and finally a decarboxylation reaction occurs [13].
The oligoalkyl succinic anhydride obtained in this way is aminated. Diethylenetri-amine was used as the aminating component. Amineification is carried out as follows: a calculated amount of alkenyl amber anhydride in toluene is poured into a three-necked flask equipped with a heater, thermometer and dropper funnel. The thickener is activated to ensure that the temperature rise from the dropper funnel stops (the reaction is exothermic). The drip funnel is then replaced with a Din-Stark holder,
the temperature is gradually raised to 80-90 C and maintained at this temperature for 0.5 hours; The temperature is raised to 110-1200C for the conversion of the formed amide to im-ides, and the reaction is considered complete after the release of about the calculated amount of water. The reaction product is cooled to 50-600C and mixed with petroleum oil in a 1:1 ratio.
By replacing the Din-Stark holder with a refrigerant, toluene, light fractions (if any) and excess diethylenetriamine are expelled first at atmospheric pressure and then under vacuum, resulting in a concentrate of the oligoalkenyl-succinimide additive in petroleum.
The reactions can be depicted as follows:
CH-CO-^ RH +11 O
CH - CO ^
t R - CH - CO -
CH2 - CO'
O
R - CH - CO -
CH2 - CO
"O + NH - R1-►
-H2O
R-CH- CO-
CH2 - CO
N - R1
R, R - radicals, respectively, of co-oligomer of hexene-1 with dicyclopentadiene and in amino derivatives.
As a result of this reaction, it is possible to obtain bisuxinimide along with mono-succinimide, which is not desirable, as in this case, along with an increase in viscosity, a decrease in alkalinity is observed. By taking too much amine, the reaction can be carried out mainly in the direction of monosuccinimide.
When studying the structure of the synthesized diethylenetriamine olthoalkenylsuccin-imide by IR spectroscopy, it was revealed that the spectrum contains absorption bands at 2930 and 2945 cm-1 characterizing CH2 groups of the alkenyl radical, 1610 and 1639 cm- are double bonds in both dicyclopentadiene rings, 1703 and 1705 cm-1 are imides and 3060 and 3085 cm-1 are amino groups.
IR spectra were taken on a Perkin Elmer 16 PC FT-IR Fourier spectrometer in vaseline oil.
The obtained oligoalkenylsuccinimide di-ethylenetriamine is a high-viscous product of brown color, which has the following characteristics: molecular weight 900-1000; alkaline number - 18-20 mgKOH/g; nitrogen content (determined by the Dumas method) - 2.7-3.0%.
In order the facilitate work with the addition, in view of its viscosity, a concentrate was prepared in M-6 oil in a ratio of 1:1, the viscosity of which at 1000C is 100-120 mm2/sm-1.
Results and discussion
The Figure shows the effect of the amount of diethylenetriamine on the detergent properties (according to the toughened n3B method) of the synthesized succinimide additive. It shows that the optimal amount of diethylenetriamine is 3 w.p. for 100 w.p. derivative of succinic acid anhydride.
-1=1
О i/l
3
The amount of diethylenetriammeL w.p
Effect of the amount of diethylenetriamine (per weight part of 100 g of the product) on the detergent properties of the resulting succinimide additive.
The effect of the new synthesized additive AKI-636 on the physicochemical and functional properties of oils in comparison with known succinimide additives such as C-5A (obtained on the basis of polyisobutylene), HXn -476 (obtained on the basis of isobutylene-styrene cooligomer) [6] and synthesized by us in the laboratory AKI-634 (based on hexene-1-
styrene cooligomer) [7] and AKI-635 (based on hexene-1 - indene cooligomer) [8] (Table).
Anticorrosive properties were determined according to ГОСТ 20502-75, method for determination of detergent potential - ГОСТ 10734-64.
The Table shows that the experimental sample meets the requirements for industrially produced C-5A additive and, in addition to
increasing the value of the viscosity index of the oil (due to its polymeric nature, the synthesized succinimide additive increases the viscosity index of oils), it also has anti-corrosion properties, which is due to the chemical structure of the raw material. The anticorrosive property of the additive is due to the presence of carbocy-clic dicyclopentadiene manganese in the mole-
Conclusion
Thus, the results of the research show that it is possible to obtain a multifunctional succin-imide-type polymer additive using hexene-1-di-cyclopentadiene joint oligomers. The resulting additive, having a detergent-dispersant effect, also improves the viscosity-temperature, antioxidant and anti-corrosion properties of petroleum oils, while expanding their raw material resources.
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Physico-chemical and functional properties of succinimide additives
Indicators Succinimide additives
C-5A ИХП-476 AKI-634 AKI-635 New AKI-636 (concentrate)
Kinematic viscosity at 1000C, mm2-s-1 150-300 66 180-200 180-200 100-120
Alkali number, mgKON/g 20 17.5 14.0-17.0 18.0 17.0-20.0
Nitrogen content,% 1.4 1.2 1.6-1.8 1.3 1.2-1.38
M-6 oil+1.5% additive: a) corrosion, g/m2 b) Viscosity index 10 3.7 2.0 2.1 2.1
(with ДФ-11 additive) (without additive ДФ-11)
83 85 95 93 94
Washing potential, % 90 96 95 95 96
olunmuç "Müasir kimyanin aktual problemlari" .eyn. succinimide additive on the basis of Hexen-1-
Elmi konf. mater. 2-4 oktyabr. 2019. Baki. S. 266. inden oligomer. Chemical Problems. 2018. V. 16.
16. Hasanova E.I., Nazarov R.H, Hamidova C.S, Isa- No 2. P. 245-249. kov E.U. Obtaining and research of polyalkenyl-
MOTOR YAGLARINA MODIFIKASIYA OLUNMU§ POLÎALKENÎL SUKSiNIMID A§QARI
C.Ç.Hamidova, E.U.Isakov, E.LHasanova, N.C.Hüseynova
Maqala müharrik yaglarinda açagi temperaturlardada çôkûntûnûn qarçisinin alinmasi ûçûn an çox istifada edilan açqarlardan birinin - polialkenilsuksinimidin kimyavi modifikasiya olunmuç versiyasinin sintezina hasr edilmiçdir. Bu açqarlar malein anhidridinin a-olefin oliqomeri ila alkillaçdirilmasi va sonra alinan oliqoalkenilkahraba anhidridinin müxtalif aminlarla reaksiyaya ugratmaqla alda edilir. Yeni açqarin sintezinda, heksen-1-in disiklopentadienla birga oliqomeri alkillaçdiriri agent kimi istifada edilmiçdir ki, bu da polimer açqarlarinin sintezinda istifada olunan oliqomer birlaçmalarin xammal ehtiyatlarini geniçlandirmaya, hamçinin alinmiç açqara antikorroziya xüsusiyyatlarini vermaya imkan verir ki, bu da tarkiba ditsiklopentadien halqalarini daxil etmakla mümkün olur. Alinan birlaçmanin tarkibi va quruluçu müvafiq fiziki-kimyavi tadqiqat üsullari ila ôyranilmiçdir. M-11 yaginda açqarin 1.5% miqdar olmasi yagin korroziyasini tamamila aradan qaldirir va yuyuculuq xassalarini yaxçilaçdinr va bu da daha sada tarkibli sürtkü kompozisiyasi yaratmaga im-kan verar va naticada iqtisadi samara alda olunar.
Açar sözlzr: a§qar, suksinimidbr, malein anhidrid, heksen-1, ditsiklopentadien, alkenil süksinimid anhidrid, dietilentri-amin, suksinimid a§qarlari.
МОДИФИЦИРОВАННАЯ ПОЛИАЛКЕНИЛСУКЦИНИМИДНАЯ ПРИСАДКА ДЛЯ
МОТОРНЫХ МАСЕЛ
Д^Ш.^мидова, Э.У.Исаков, Э.И.Гасанова, Н.Дж.Гусейнова
Статья посвящена синтезу химически модифицированной версии одной из важнейших присадок для предотвращения низкотемпературных осадков в моторных маслах - полиалкенилсукцинимида. Эту присадку получают путем алкилирования малеинового ангидрида олигомером a-олефина и последующего взаимодействия полученного олигоалкенилянтарного ангидрида с различными аминами. В качестве алкилирующего агента использовано новое соединение - олигомер гексена-1 с дициклопентадиеном, что позволяет расширить сырьевые запасы олигомерных соединений, используемых при синтезе полимерных присадок, а также придать антикоррозионные свойства присадкам путем введения в состав дициклопентадиеновых колец. Состав и структура полученных соединений изучены соответствующими физико-химическими методами исследования. Содержание 1.5% полученной присадки в масле М-11 полностью исключает коррозию масла и улучшает моющие свойства. А это позволяет создавать смазочный состав с более простым составом и, как следствие, дает экономический эффект. Опытный образец соответствует требованиям к промышленно -выпускаемой присадке С-5А и, кроме повышенного значения индекса вязкости масла, он также обладает антикоррозийными свойствами, что обусловлено химической структурой сырья, т. e. наличием в молекуле карбоциклического дициклопентадиенового фрагмента.
Ключевые слова: присадки, сукцинимиды, малеиновый ангидрид, гексен-1, дициклопентадиен, алкенилян-тарный ангидрид, диэтилентриамин, сукцинимидные присадки.
