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CHEMICAL PROBLEMS 2020 no. 2 (18) ISSN 2221-8688
<S
UDC 665.7.038
SYNTHESIS OF ALLYLCAPRYLATE-STYRENE COPOLYMERS WITH STYROLE AND THEIR RESEARCH AS A VISCOSITY ADDITIVE TO
LUBRICANT OILS
J.Sh. Hamidova, L.K. Kazimzade, E.I. Hasanova, E.U. Isakov, S.S. Babayev
Academician A.M.Guliyev Institute of Chemistry of Additives, Beyukshor Highway, Block 2062, Baku, AZ1029 (+9912)5149612 E-mail: c.hamidova@mail.ru
Received 06.02.2020. Accepted 02.04.2020
Abstract: The article presents results of copolymerization of allyl ether of caprylic acid -allylcaprylate with styrene in line with radical mechanism, the influence of the main factors -the composition of primary monomers and initiator consumption on the process, as well as results of studies synthesized copolymer as a viscosity additive in the composition of lubricating oils. It found that samples of synthesized polymer compounds are on a par with industrial additives of the polyalkylmethacrylate type on improving viscosity-temperature properties, but have higher operational characteristics than industrial additives in terms of resistance to thermal effects due to the stabilizing effect of styrene units. The study into samples of synthesized copolymers as oil additives showed that depending on specific requirement, a polymer compound of any molecular weight can be synthesized in high yield for use as viscosity additive for these oils.
Keywords: caprilic acid, allyl alcohol, allylcaprate, styrene, copolymer, viscosity additive, petroleum oil
DOI: 10.32737/2221-8688-2020-2-158-163
Introduction
Obtaining of basic oils with high viscosity index is one of the urgent problems of present- day oil chemistry. The higher the viscosity index value which characterizes viscosity- temperature properties of oils, the lesser the viscosity of oils changes due to the effect of temperature and can be considered valuable. Viscosity-temperature properties of oils are determined with due regard for their chemical composition, purification degree, development level of production technology and so on. It is possible to obtain a required value of viscosity index by changing the above-mentioned factors. The simplest, economically profitable and rational way of oils production with high viscosity index is the use of petroleum oils - viscosity additives comprising a small amount of polymer compounds, i.e. it is possible to achieve any result with the least material expenses.
Oil-soluble polymers and copolymers of polyisobuthylenes, polyalkylmethacrylates and
other vinyl monomers are used as viscosity additives [1-4]. However, these additives meet no requirements of modern techniques on resistance to destructive effects.
The analysis of research works on the synthesis and study of polymethacrylate additives shows that obtaining of complex ether polymers are more promising than hydrocarbon type polymers, for they are obtained by simple technology and improve viscosity-temperature properties of oils more effectively. From this point of view, to expand the feedstock of monomers used for obtaining of viscosity additives complex allyl ethers were synthesized and certain researches were carried out to obtain synthetic and petroleum oils by polymerizing them with vinyl monomers [5-8].
The present paper explores results of experiments performed to obtain viscosity additives for petroleum oils using allyl monomers - allyl ether of caprilic acid
CHEMICAL PROBLEMS 2020 no. 2 (18)
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(octanoic acid) - allylcaprylate.
As is known, allyl monomers are not polymerized separately; however, they easily enter into copolymerization reaction. That's why obtained monomers (allylcaprylate) were
copolymerized with styrene. Styrene is one of the cheap monomers of oil chemistry and inclusion of styrene units into open chain polymer macromolecule gives stability to copolymers to thermal impacts.
Experimental part
Allylcaprylate is obtained by influencing caprilic acid with allyl alcohol through the well- known etherification reaction.
Caprilic acid (octanoic acid) and allyl alcohol were taken as a reactive. Both acid and allyl alcohol are included into etherification reaction in a freshly distilled form. Physical and chemical properties of an acid: mol. mass Mr = 144.2, melting temperature Tmelt. = 16.63oC, boiling temperature Tboil. =239.3oC/760 mm (124710 mm), refraction coefficient nD = 1.4280, density d420 = 0.99089 q/cm3, physical and chemical properties of
allyl alcohol: mol. mass Mr = 58.8, melting temperature Tmelt. = -129oC, boiling temperature Tboil. = 97oC, refraction coefficient nD = 1.4133, density d4® = 0.854 g/cm3.
The reaction was methodically performed as follows. Calculated amount of reagents, certain amount of toluene (to separate water by azeotropic distillation), KU-2 cationite in the amount of 1% of reaction mixture were added to three necked flask supplied with Dean-Stark apparatus and the mixture was heated at 110-1200C temperature by mixing till water boiling:
C№(C№>COOH + CH2 == CH — CH2OH -.— ► CH3(CH2)6COOCH2 CH = CH2 + H2 O
Upon completion of the process, KU-2 catalyst was separated from the filtering system, the product was washed off with hot water distilled in vacuum after traces of toluene and allyl alcohol were separated. Obtained allyl ether was used in copolymerization with styrene.
Synthesized allylcaprate ether had the following physical and chemical properties: Mr = 184, nD = 1.4276, d420 = 0.909 g/cm3.
Styrene was used as a chemical reagent in distilled form; its physical and chemical properties were as follows: Mr = 104.15, nD = 1.5465, d20= 0.909 g/cm3, melting temperature Tmelt. = -30.06oC, boiling temperature Tboil. = 145oC.
Copolymerization was performed in solution medium (hexane or heptane) with the presence of dinitrile of azo-(bis)-isooil acid as an initiator using radical polymerization mechanism. The effect of copolymerization condition on the properties of copolymer was studied and the results given in Table 1.
The composition and structure of synthesized compounds were studied using IR-and NMR-spectroscopy methods.
Thermal resistance of synthesized copolymer was determined by reduction of viscosity depending on the probation occurring in 5% of solution in Turbin "L" oil using known technique [10].
Results and discussion
As Table 1 shows, the main factors influencing the process are the composition of primary monomer and amount of an initiator (Table 1). The rise of styrene in monomer mixture from 5% to 25% causes the increase in the yield of copolymer from 25.0% to 91.3% and molar mass from 3000 to 8000. This is explained as being due to the fact that styrene has a high polymerization property and the rise
in its amount in monomer mixture causes the process acceleration and the rise in yield and molar mass. Allyl monomers are not polymerized separately, i.e. form no homopolymers and enter into polymer chain due to copolymerization. Thus, amount of allyl monomers must not be higher than 50 mol% and when the amount of it exceeds the given value the yield of copolymer and molar mass
decrease. The increase of initiator amount from however causes the decreases of molar mass 0.3% to 1% raises the yield of copolymer, and this is typical for radical polymerization.
Table 1. Copolimerization of allylcaprylate with styrene
Copolymerization condition Character of
copolymerization
Amount of styrene Molar
in monomer Amount of Duration of Temperature Yield, mass mass
mixture, mass % initiator, % process, hour (oC) %
5 1 4 75 25.0 3000
10 1 4 75 53.4 4000
15 1 4 75 60.8 5000
20 1 4 75 85.5 7000
25 1 4 75 91.3 8000
20 0.3 4 75 50.1 9000
20 0.5 4 75 71.2 8000
20 0.7 4 75 77.3 7500
20 1 4 75 83.4 7000
20 1 3 75 77.8 7000
20 1 6 75 79.9 7100
20 1 4 65 76.5 7200
20 1 4 85 81.5 7000
Temperature changes in the range of 65-85oC and increase of polymerization duration do not influence the process sharply while an amount of initiator taken less than 1% causes the decrease in yield and increase in molar mass. That's why reaction conditions that provide the high yield and molar mass parameters can be selected as follows:
temperature 75 0C, process duration 4 hours, amount of an initiator for monomer mixture -1.0%. The structure of synthesized copolymer was studied by IR- and NMR-spectroscopy methods and according to results obtained the following schematic general formula was proposed for obtained copolymers:
-ch2 — ch
2 I
ch
-a ch,—
ch
coor
n
C6H5
n+m
here n = 8-19, m = 18-34, R - caprilic acid radical
Synthesized copolymer was studied as viscosity additive for lubricants. The impact of viscosity-temperature properties of H-12A
petroleum oil on copolymer density with molar mass of 8000 was studied and the results given in Table 2.
Table 2. Impact of copolymer density on viscosity-temperature of H-12A oil
Density of copolymer, mass %
Kinematic viscosity of oil concentrated at 100oC,
_mm2/eec_
Viscosity index (VI)
0
0,5 1 2 3 5 7
3.11 3.67 4.22 5.53 6.29 8.03 9.09
89
104
114
132
134
136
136
As Table 2 shows, rise in the density of oil copolymer from 0.5% to 5% led to the increase in viscosity index (VI) from 89 to 138. Further increase in density (7%) did not cause the increase of viscosity index and that was general regularity of concentrating oils. In considering that the demand VI for concentrated oils with viscosity of 8±0.5 mm2/sec at 100oC must not be less than 125, according to Table 2, we may obtain oil with required properties by adding 5% of copolymer into H-12A oil.
The influence of molar mass of synthesized copolymer on viscosity-temperature properties of H-12A oil was studied. Oil was concentrated and studied with
According to Table 3, examined samples are in the same level with industrial viscosity additive - polyalkylmethacrylate for
copolymer at 100oC till kinematic viscosity reached 7.5-8.5 mm2/sec. Results were summarized in Table 3 and all samples used to concentrate oil met the requirements for VI value. However, with the reduction of molar mass it is necessary to increase the amount of copolymer in oil content to achieve the required value of viscosity of oil and this is not economically effective. The increase in molar mass causes decreases resistance of copolymer in oil content to destructive effects. Molar mass value of copolymer to be used as a viscosity additive is selected relevant to a certain demand put for resistance of concentrated oil.
improving viscosity-temperature properties of H-12A oil.
Thermal resistance of synthesized
Table 3. Influence of molar mass of synthesized copolymer on viscosity-temperature
properties of H-12A oil
Characteristics
copolymer concentrated oil
molar mass density,% kinematic viscosity at 100°C, MM2/C viscosity index
10000 4.0 7.6 136
9000 5.5 7.9 133
8000 6.0 7.8 130
5000 9.0 7.9 128
3000 10.2 7.6 125
Polyalkyl methacrylate
10000 4.1 8.1 138
copolymer samples was studied in comparison with known viscosity additives polyisobuthylene and polyalkylmethacrylate by heating their 5% solutions in turbine "L" oil at 200oC for 12 hours. It was determined that synthesized copolymer exhibits higher operating characteristics than
polyalkylmethacrylate type industrial additives due to its resistance to thermal effects. For oil
concentrated with copolymer the reduction of viscosity due to destruction is 7.0-7.5%, and this indicator is into the range of 9.5-11.4 and 13.7A17.9% for polyisobuthylene and polyalkylmethacrylates, accordingly. These results show that the inclusion of cyclic aromatic fragment in styrene molecule into copolymer increases resistance of obtained macromolecular compound to thermal effects
Copolymers of allyl ether -allylcaprylate of caprilic acid with styrene were obtained by means of radical copolyemrization. Also, the composition of primary monomers and amount of initiator -the main factors that influence the process were determined. It revealed that the rise in the styrene amount of monomer mixture caused the increase in yield of copolymer and molar mass. This was explained as being due to the fact that styrene had a high polymerization property and the increase in its amount in monomer mixture led to the process acceleration and increase in yield of molar mass. The amount of allyl monomers in copolymer of more than 50 mol% reduced the yield of copolymer and molar mass. The increase of initiator amount from 0.3% to 1%
raised the yield of copolymer, however, decreased the molar mass and this is believed to be typical for radical polymerization. Synthesized triple copolymer samples were studied as viscosity additives to petroleum oils and it found that depending on the demand may use these oils as viscosity additives by synthesizing any high molar mass copolymers with high yield.
Since synthesized copolymer samples are in the same level with polymethacrylate industrial additives in terms of improving viscosity-temperature properties of oils, the results showed their higher operating indicators in terms of thermal resistance and this case must be explained by stabilizing effect of styrene units.
References
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Pertochemistry. 2009, no. 5, pp. 31-33. (In Russian).
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10. Motor and reactive oils and fluids. Moscow: Himiya Publ., 1964, pp. 123.
ALLiLKAPRiLAT-STiROL BiRGd POLiMERJMNSINTEZi Vd SURTKU YAGLARINA
OZLULUKAgQARIKiMi TdDQiQi
C.§. H9midova, L.K. Kazimzad9, E.i. H9S9nova, E.U. isakov, S.S. Babayev
АМЕА akad. Э. Quliyev adina A§qarlar Kimyasi institutu AZ1029, Baki §dh., Boyuk§or §ossesi, mdhdlld 2062 Tel.: (+9912)5149612
e-mail: c.hamidovaamail.ru
Mdqalddd kapril tur§usunun allil efirinin - allilkaprilatin stirolla birgd polimerinin padikal mexanizmi uzrd birgd polimerld§mdsinin, prosesd dsas amilldrin - ilkin monomer qari§iginin vd inisiatorun tdsirinin vd birgd polimerin surtku yaglarinin tdrkibindd ozluluk a§qari kimi tddqiqinin ndticdldri verilmi§dir. Mudyydn edilmi§dir ki, sintez edilmi§ birgd polimer numundldri yaglarin ozluluk-temperatur xassdldrini yax§ila§dirmaga gord polialkilmetakrilat tipli sdnaye a§qarlari ild eyni sdviyyddd oldugu halda, termiki tdsirldrd qar§i davamliliqlarina gord onlardan daha yuksdk istismar gostdricildrind malikdirldr ki, bu hal isd stirol manqalarinin stabilld§dirici tdsiri ild izah olunmalidir. Sintez olunmu§ birgd polimer numundldrinin neft yaglarina ozluluk a§qarlari kimi tddqiqi gostdrmi§dir ki, tdlabatdan asili olaraq istdnildn molekul kutldyd malik yuksdk giximli birgd polimerldr sintez eddrdk, bu yaglara ozluluk a§qari kimi istifadd etmdk olar.
Agar sozfor: kapril tur§usu, allil spirti, allilkaprinat, stirol, birgd polimer, ozluluk a§qari, neft yaglari
СИНТЕЗ СОПОЛИМЕРОВ АЛЛИЛКАПРИЛАТА СО СТИРОЛОМ И ИССЛЕДОВАНИЕ ИХ В КАЧЕСТВЕ ВЯЗКОСТНЫХ ПРИСАДОК К СМАЗОЧНЫМ
МАСЛАМ
Д.Ш. Гамидова, Л.К. Кязимзаде, Э.И. Гасанова, Э. У. Исаков, С. С. Бабаев
Институт химии присадок им. акад. А.М. Кулиева Национальной АН Азербайджана AZ1029, Баку, Беюкшорское шоссе, квартал 2062. Тел .: (+9912) 5149612
e-mail: c.hamidova@mail.ru
В статье представлены результаты исследования сополимеризации аллилового эфира каприловой кислоты - аллилкаприлата со стиролом по радикальному механизму, влияния состава смесей исходных мономеров и расхода инициатора на процесс, а также результаты исследования синтезированного сополимера в качестве вязкостной присадки к смазочным маслам. Установлено, что образцы синтезированных полимерных соединений по улучшению вязкостно - температурных свойств находятся на одинаковом уровне с промышленными присадками полиалкилметакрилатного типа, но имеют более высокие эксплуатационные характеристики, чем промышленные присадки по устойчивости к термическим воздействиям, что обусловлено стабилизирующим действием стирольных звеньев. Исследование образцов синтезированных сополимеров в качестве присадок показало, что в зависимости от конкретных требований, предъявляемых к маслам, могут быть синтезированы полимерные соединения с различной молекулярной массой и высоким выходом для использования их в качестве вязкостной присадки к маслам.
Ключевые слова: каприловая кислота, аллиловый спирт, аллилкаприлат, стирол, сополимер, вязкостные присадки, нефтяные масла.
