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AZ9RBAYCAN KIMYA JURNALI № 3 2013
UDC 665.7.038
IMPROVING VISCOSITY-TEMPERATURE PROPERTIES OF PETROLEUM OILS BY USING OLIGOMERS AND COOLIGOMERS OF C6-a-OLEFINS
A.I.Ahmadov, J.Sh.Hamidova, E.U.Isakov, F.J.Adigezalova
Azerbaijan National Academy of Sciences A.M.Guliyev Institute of Chemistry of Additives
aki05@mail.ru Received 05.11.2012
The results of studies on oligomerization of C6 a-olefins and their double cooligomerization with dicyclopentadiene, indene and styrene have been cited. Obtained oligomeric compounds of various molecular mass and composition were used as synthetic components in composition of petroleum oils for improving their viscosity-temperature properties.
Keywords: viscosity-temperature properties, petroleum oils, oligomers, cooligomers, a-olefins.
Operating characteristics of oils such as viscosity and viscosity-temperature properties specify possible temperature scope of their application since viscosity level defines viscosity grade of lubricating oils. Production of oils with improved viscosity-temperature characteristics is therefore one of the most important problem in petrochemistry.
Production of oils with better viscosity-temperature properties is usually carried out by adding polymeric compounds, namely viscosity-index improvers into their composition. However, during the operation cycle improvers are being destructed under thermal and mechanical influence, the molecular mass of initial polymer decreases and viscosity of the thickened oil drops below acceptable level [1, 2].
In order to improve viscosity-temperature properties of petroleum oils and to avoid shortcomings mentioned above, it was proposed to include into composition different synthetic components - relatively low-molecular polymers, e.g. oligomers and cooligomers of a-olefins that are not subjected to destruction during operations.
EXPERIMENTAL
Synthesis of the indicated components has been carried out by oligomerization and double cooligomerization of C6-olefins with indene, dicyclopentadiene or styrene. Oligomers of C6-olefines, as well as their double cooligomers with indene, dicyclopentadiene and styrene have been synthesized. Hexene-1 and 4-methylpentene were used as initial C6-olefins. Oligomerization and cooligomerization were carried out in the presence of AlCl3 at 20-400C [2]. At the catalyst concentration 0.1-0.3% the outcome of oligomer was insignificant. Increase of catalyst consumption to 0.5-0.8% resulted in outcome increase up to 80-93%. In this case molecular mass value is not considerably changed; as long as during ionic polymerization molecular mass value doesn't depend on catalyst concentration. Further the increase of catalyst consumption to 1-2% does not change the outcome and molecular mass of oligomer. It was therefore decided to keep consumption of aluminium chloride within the range of 0.8-1.0% for a-olefin used in oligomerization.
Oligomerization of 4-methylpentene-1 results in obtaining of higher molecular products than oligomerization of its unbranched analogue - hexene-1 within similar conditions. It is explained by structural peculiarities of compounds. As a matter of fact, methyl groups, being strong electron-donors, raise the activity towards cationic polymerization.
In case of hexene-1 methyl group is joined by the third carbon atom with relation to double bound, while in 4-methyl-pentene-1 two methyl groups are joined by the second carbon atom
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with relation to double bound that determines different behaviour of indicated monomers during reaction of oligomerization.
To enhance thermal stability of synthesized oligomers and create an additional reaction centre for conducting chemical modification, parent a-olefins - hexene-1 or 4-methylpentene-1 were put to cooligomerization with indene, dicyclopentadiene or styrene. It has been found that insertion of these comonomers into cooligomerization with C6-olefins leads to reduction of molecular mass value that in turn means the involvement of cyclic comonomers in restricting the length of oligomeric chain at the expense of alkylation.
It should be pointed out that comonomers of a-olefins used during the tests are industrial products within reach that proves the reasonability of carried out investigations since the interest to chemical product is strictly determined by the availability of raw material resources.
Structures of the obtained products have been studied by IR- and PMR-spectroscopic methods. It was found out that links of 4-methylpentene-1 enter into oligomeric chain in rather isomerized form, like creating formation of cooligomer with hexene-1 and 4-methylpentene-1 links [3]:
^CH2=CH-CH2CH(CH3)2
—CH2-CH
CH2-CH-
v H2C J n-m V C4H9 J H3C-CH-CH3
Chemical bound between comonomers links is absent, i.e. as a result we have got a pure cooligomer with alternated monomer links that determined physico-chemical properties of synthesized compounds included into lubricant oils.
RESULTS AND DISCUSSION
Investigations carried out have been resulted in obtaining oligomeric compounds with molecular mass about 700-2000 and outcome 87-92% depending on conditions of reaction and on the ratio of initial monomers.
Synthesized oligomers and cooligomers were examined as synthetic components of petroleum oils for improving their viscosity-temperature characteristics.
Effect of hexene-1 cooligomer with dicyclopentadiene on viscosity-temperature characteristics of M-6 oil (Table) has been given as an example. As it was indicated, cooligomer at concentration 20-30% helps to obtain basic oil with viscosity about 8±0.5 mm2/sec at 100oC.
Effect of hexene-1 cooligomer with dicyclopentadiene on viscosity-temperature characteristics of M-6 oil
Cooligomer amount, % Viscosity at temperature (0C), mm2/sec Viscosity index Corrosion, g/m2
40 100
0 39.14 5.8 80 180
5 44.8 6.2 82 160
20 67.1 7.9 90 90
30 70.0 8.5 93 42
40 74.7 9.0 96 5.0
50 79.1 9.9 101 4.6
Note, that cooligomers both with indene and dicyclopentadiene links have anticorrosive properties as well; at the concentration 40-50% they completely eliminate corrosiveness of M-6 oil.
As it was proved [1], corrosiveness is the consequence of oxidation and has been caused by oxidation products. Apparently, inserting of carbocyclic (dicyclopentadiene) and aromatic (indene) links into oligomeric chain causes the chemical modification of the structure, and
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comonomeric fragments add impart antioxidative properties to the synthetic component. As a result of mentioned above the compound also acquires anticorrosive properties.
The carried out investigation indicated that synthesized oligomeric compounds slightly differ from each other in improving viscosity-temperature properties of distillate oils. In general, reaction of cooligomerization may be represented as follows:
CH2=CH + A —> -CH2-CH-A- , 2 I 2 I ,
R R
where R= -C4H9 or -CH2-CH(CH3)2 ,
A= CH2=CH ;
Л
A,
or
ЧА/
Investigations in the field of cooligomers synthesis being used as petroleum oils component, and initial raw material in polyfunctional additives are going on [4].
REFERENCES
1. Кулиев А.М. Химия и технология присадок к смазочным маслам и топливам. Л.: Химия,1985. 312 с.
2. Ахмедов А.И., Фарзалиев В.М., Алигулиев Р.М. // Полимерные присадки и смазки. Баку: Элм, 2000. 174 с.
3. Ахмедов А.И., Мамедова Д.А. // Химия и технология топлив и масел. 2003. № 3. С. 28-31.
4. Ахмедов А.И., Гамидова Дж.Ш. // Нефтехимия и нефтепереработка. 2010. № 1. С. 29-32.
NEFT YAGLARININ OZLULUK-TEMPERATUR XASS3L3R1N1N C6 a-OLEFlNL3RlNlN OLlQOMER V3 S00L1Q0MERL3R! !L3 YAX§ILA§DIRILMASI
3.1.3hmadov, C.§.Hamidova, E.U.lsakov, F.C.Adigozalova
Maqalada C6 a-olefinlarinin oliqomerla§masi va ditsiklopentadien, inden va stirolla ikiqat birga oliqomerla§masi yolu ila sintetik komponentlarin sintezi uzra tadqiqatlarin naticalari verilir. Muxtalif molekul kutlasina va tarkiba malik oliqomer birla§malari alinmi§ va neft yaglarinin tarkibinda onlarin ozluluk-temperatur xassalarini yax§ila§diran sintetik komponentlar kimi istifada edilmi§lar.
Agar sozlsr: ozluluk-temperatur xassdhri, neft yaglari, oliqomerhr, birga oliqomerhr, a-olefnhr.
УЛУЧШЕНИЕ ВЯЗКОСТНО-ТЕМПЕРАТУРНЫХ СВОЙСТВ НЕФТЯНЫХ МАСЕЛ ОЛИГОМЕРАМИ И СООЛИГОМЕРАМИ a-ОЛЕФИНОВ С6
А.И.Ахмедов, Д.Ш.Гамидова, Э.У.Исаков, Ф.Д.Адигезалова
Приведены результаты исследований по олигомеризации a-олефинов С6 и их двойной соолигоме-ризации с дициклопентадиеном, инденом и стиролом. Полученные олигомерные соединения различной молекулярной массы и состава были использованы в качестве синтетических компонентов в составе нефтяных масел с целью улучшения их вязкостно-температурных свойств.
Ключевые слова: вязкостно-температурные свойства, нефтяные масла, олигомеры, соолигоме-ры, а-олефины.
