Chemical Compositions and Classification of Crude oil – type of Ondo State bitumen exudate. H.O. Ogunsuyi*, K.O. Ipinmoroti and O.O. Ajayi. Department of Chemistry, Federal University of Technology, P.M. B. 704, Akure, Nigeria Abstract. The chemical constituents of the maltene component of bitumen sample obtained from Agbabu in Odigbo Local Government area of Ondo State were examined using GC – MS. Out of the 72 peaks recorded on the chromatogram (Fig.1.0), only 67 compounds were identified representing 96.82% of the total crude- oil. The major constituents were alicyclic hydrocarbon (44.59%), alkanes (28.61%) and polar compounds (13.71%). The minor constituents were the mono aromatic hydrocarbons and the olefins which recorded 3.47% and 6.44% respectively. The different classes of compounds so identified comfirmed that the bitumen shared close similarities with the conventional crude oil. However, the classification of the bitumen into crude oil-type revealed that it is asphaltic – resinous type of crude oil, unlike the conventional crude oil that are often times paraffinic in nature. Hence, different refinery infrastrctures are required for the refining and upgrading of the bitumen exudates. The varieties of chemical compounds constituting the bitumen exudate can be converted into useful petrochemical products. Key words. Bitumen exudate, Chemical constituents, crude oil –type classification. *Author for correspondence: olayinkaogunsuyi @yahoo.com. Introduction. Petroleum samples obtained from reservoir rocks and bitumen extracted from fine-grained rocks have many similarities, but they also exhibit many important differences. There is no doubt that they are related; indeed, bitumen is almost universally accepted as the direct precursor for petroleum (Stoneley, 1995). Both bitumen and petroleum exhibit a wide range of compositions and this has been attributed to the source –rock facies and the composition of the kerogens that generated the bitumen. The chemical composition of bitumen is complex and varies considerably depending upon the geology of the sources, age and feedstock and this dictates the method of manufacture. It is essentially of a hydrocarbon nature with great variety of hydrocarbons present, mostly of high molecular weight together with complex molecules including a certain proportion of heteroatoms of nitrogen, oxygen and sulphur. The most widely accepted concept of the constitution is that bitumen is made up of three major components. The first is described as a mixture of asphaltenes, which are high molecular weight complex molecules, insoluble in paraffinic hydrocarbons such as n-heptane and soluble in aromatic hydrocarbon such as benzene. The second component is described as a mixture of resin and the third is mineral oil (Allinson,1975). Among the several standard analytical techniques employed to characterise hydrocarbon fraction of heavy crude oil and petroleum products are: Gas chromatography-simulated distillation; (ASTM D-2, 1976; ASTM D-2425,1989; Oluwole et al 1985,), Gas chromatography- Mass spectrometry( Zeman and Bartl, 1978; Yu and Hites, 1981; Yergey and Risby, 1982; Wang et al,1994), High performance - Liquid chromatography, (Altgelt and Gouw, 1975; Altgelt et al, 1979), Single column adsorption chromatography (ASTM- D- 2007, 1989; Allula et al, 1989) e.t.c..Some of the reviewed work had shown that knowledge of composition of any crude oil is an important tool in determininig the class of crude oil it belongs and this information is valuable to refiner who intends to know the quantity of the successive distillates that can be obtained from the crude oil (Kinghorn,1983). Several classification methods based on both the physical and chemical classifications had been reported by previous workers among which are US Bureau of Mines classsification (Smith,1966), Correlation index and Approximate summary (Gruse and Steven,1960), Chemical classifications (Tissot and Welte’s, 1978 and Sachanen, 1950). Previous researches conducted on some Nigerian bitumen samples had revealed that the synthetic crude obtainable from the mineral oil could serve as refinery feedstock for the production of motor fuel and fuel oil which are quite similar to those derivable from the conventional petroleum (Ondo State Government, 1982 and Adegoke, et al 1991). However, none of the previous studies had documented the classification of the heavy crude oil deposit in Odigbo Local Government area.. In view of the fore–going the present study aims at classifying the bitumen exudate from Agbabu into crude oil type on the basis of its chemical constituents following Tissot and Welte’s chemical classification. This information would aid decisions on the best way to refine the heavy oil. Materials and Method. Sample collection. Bitumen samples were collected from the borehole deposit located at Agbabu in Odigbo Local Government area of Ondo State. The sample location lies within latitude 06o 35’ 556N to 060 39’ 169N and Longitude 4o 49’ 769E to 40 53’ 409E. The exudate was drawn from the bulk deposit four times and homogenized thoroughly to obtain its representative sample.. Solvent Extraction. Soxhlet extraction method (Jacob and Filby, 1983) was adopted to extract the bitumen samples. Eighty grams (80g) of the sample were placed in cellulose extraction thimble (Whatman 33mm x 94mm) and extracted with 250ml of toluene (Baker reagent) for 12 hours until the liquid siphoning to the flask was clear. The toluene extract was vacuum evaporated using rotary evaporator (Buchi, Rotavapor-RE, 218336) at 40oC to recover the crude bitumen extract. The extract was left open to allow the solvent evaporate off completely. Precipitation of asphaltene from the crude extract. Ten grams (10g) of the crude extract were weighed inside a 250ml conical flask and 100ml npentane was added into the flask. The mixture was mixed with glass rod to ensure thorough mixing and left to stand for 10mins. The asphaltene precipitated out of the saturated hydrocarbon solvent and was recovered after centrifuging the mixture for 3 mins and decanting the solvent using a Pasteur pipette. The asphaltene was rinsed with small portion of the solvent thrice until the solvent became clear. To further ascertain that the maltene was rid off the precipitated asphaltene, the maltene was filtered through filter paper with the aid of vacuum pump. Identification of the maltene components. The identification of the chemical constituents and various hydrocarbons embedded in the samples were conducted by GC/MS using direct injection in the split mode under the following conditions; 1200MS Varian equipped with HP 5MS column: 30m x 0.25mm x 0.25. Hydrogen was used as carrier gas at 1.0ml/min flow rate; Initial oven temperature was 500C then ramped at 2.50C/min to 3200C for 10mins The quantitative identification of different constituents was performed by comparison of their retention times and fragmentation patterns with those of the library. Classification of the crude oil. The bitumen exudate was classified into crude oil types, following the classification method of Tissot and Welte (Table 1.0). The classification was based on the concentrations of the various chemical compounds identified in the samples. TABLE: 1.0: Tissot and Welte’s crude oil classification. Saturated hydrocarbon Aromatics Saturated hydrocarbon Aromatics >50% <50% ≤50% ≥50% Crude oil type Sulphur ccontent Paraffins > naphthenes Paraffinic <1% paraffins > 0% <1% paraffins <40% paraffinicnaphthenic naphthenes <40% Naphthenes > paraffins Naphthenic <1% naphthene > 40% >1% paraffins >10% aromaticintermediate Paraffins ≥10% >1% Naphthenes ≤25% aromaticasphaltic Paraffins ≥10% <1% Naphthenes ≥ 25% aromaticnaphthenic Source: Kinghorn (1983) Results and Discussion. The various chemical constituents identified in the maltene component of the bitumen sample are as given in Table 2.0. These constituents were grouped into different classes of compounds as follows: Normal alkanes (28.61%), olefins (6.44%), alicyclic compounds (44.59%), mono aromatic hydrocarbons (3.47%) and heteroatomic compounds ( 13.71%). Normal alkanes. Most of the alkane compounds identified in the bitumen deposit were branched –chain alkanes (Table 3.0) Various isomers of n-heptane-tridecane (C7 - C13 ) were the predominant constituents of the light hydrocarbon of the heavy crudes, while the medium - heavy hydrocarbons were within the range of C25C54, most of which were straight chain alkanes e.g. pentacosane(C25H52), hexacosane(C26H54) and tetracontane(C40H82). The low molecular weight straight-chain alkanes component of the deposits are viewed to make the crude a potential source of gasolene since, in conventional crude oil, alkanes between C5 -C15 (pentane-pentadecane) are the chief constituents of straight –run (uncracked) gasolene (Kinghorn, 1983). Alkenes. The alkenes within the heavy crude (Table 4.0) were very similar to those found in conventional crude oil. Hexene, heptene, octene, and alicyclic alkenes had been identified in conventional crude oil (Kinghorn, 1983). However, the analyzed bitumen samples contained higher molecular weight olefins such as hexacosene, isomers of nonadecene and eicosene. Alkenes are quite reactive and unstable hydrocarbons, therefore high –pressure hydrogenation process (Eq.1.0) can be employed to produce more stable alkanes from them. Catalyst H (R) C=CH2 +H2 H2(R) C-CH3 (1.0) Table 2.0: ldentified chemical compounds in the maltene component of borehole bitumen S/N Compound Mol. Weight Mol. Formula Retention. Time Conc. %(w/w) 1 Methane isocyanato 57 C2H3NO 6.44 0.0.008 2 Benzene 78 C6H6 6.73 0.0.009 3. Methyl cyclopentane 84 C6H12 7.32 0.0.016 4 Cyclohexane 84 C6H12 10.29 0.0.019 5. Toluene 92 C7H8 11.26 0.0.138 6 1,1-dimethyl cyclopentane 98 C7H14 11.47 0.0.169 7 1,3-dimethylcyclopentane 98 C7H14 14.82 0.0.179 8. 1,2-dimethyl-cis-cyclopentane 98 C7H14 17.05 1.1.253 9 Methyl cyclohexane 98 C7H14 17.89 1.1.393 10 1,3-dimethyl-cis-cyclopentane 98 C7H14 19.69 1.1.664 11 3,3-dimethyl pentane 100 C7H16 21.04 1.1.627 12 3-methyl hexane (anteisoheptane) 100 C7H16 22.24 1.1.529 13 Ethyl benzene 106 C8H10 23.24 1.1.520 14 1,3-dimethyl benzene 106 C8H10 26.46 1.1.831 15. P-xylene 106 C8H10 27.51 1.1.713 16. 1,2,3-trimethyl cyclopentane 112 C8H16 28.25 2.2.762 17. 1,2,4-trimethyl cyclopentane 112 C8H16 29.44 2.2.597 18. 1,4-dimethyl cyclohexane 112 C8H16 29.55 NN/Q 19. 1,1-dimethyl cyclohexane 112 C8H16 30.04 2.2.196 20 1,4-dimethyl-cis-cyclohexane 112 C8H16 31.45 2.2.050 21 1-ethyl-1-methyl-cyclopentane 112 C8H16 32.87 2.2.779 22 1-ethyl-3-methyl-cyclopentane 112 C8H16 35.36 1.1.891 23. 1,2-dimethyl-trans-cyclohexane 112 C8H16 35.98 1.1.939 24 1,4-dimethyl-trans-cyclohexane 112 C8H16 37.81 1.1.732 25 1,2-dimethyl-cis-cyclohexane 112 C8H16 NN/Q 26 Ethyl cyclohexane 112 C8H16 38.46 2.2.081 27 2-(1,1-dimethyl ethyl)-3-methyl oxirane 114 C7H14O 40.02 1.1.624 28 3,4-dimethyl-hexane 114 C8H18 41.52 1.1.723 29 2,3,4-trimethyl-pentane 114 C8H18 43.25 1.1.688 30. 4-methyl heptanes 114 C8H18 42.82 1.1.847 31 3-methyl heptanes 114 C8H18 44.27 NN/Q 32 2-methyl-heptane 114 C8H18 46.10 1.1.745 33 3-propyl cyclohexene 124 C9H16 46.29 1.1.735 34 Methyl cyclooctane 126 C9H18 47.05 1.1.598 s35 1,1,4-trimethylcyclohexane 126 C9H18 48.16 1.1.796 36. 1-ethyl-2-methyl- cis – cyclohexane 126 C9H18 48.68 1.1.821 37 1, 2ß,,3, - trimethylcyclohexane 126 C9H18 49.42 1.1.749 38. Trans-1, 2-diethyl cyclopentane 126 C9H18 50.50 1.1.411 39. 1-ethyl-4-methyl cyclohexane 126 C9H18 50.78 1.1.389 40 2-ethyl-hexanal 128 C8H16O 53.92 1.1.523 41 2,2,4-trimethyl hexane 128 C9H20 54.17 1.1.389 42 2,3,4-trimethyl hexane 128 C9H20 54.66 1.1.351 43. 3-methyl octane 128 C9H20 54.87 1.1.268 44 3-ethyl-3-hexanamine 129 C8H19N 55.54 1.1.288 45 Pentyl-cyclopentane 140 C10H20 57.31 1.1.351 46. 2,3,3-trimethyl octane 156 C11H24 59.02 1.1.602 47. 2-n-propythiolane,s,s dioxide 162 C7H14O2S 59.90 0.0.949 48. Trans-2,4-dimethylthiane s,s,dioxide 162 C7H14O2S 60.23 NN/Q 49 2-pentyl-i-heptene 168 C12H24 61.60 1.1.821 50 2,2,4,6,6 pentamethyl heptane 170 C12H26 61.94 2.2.048 51 1,2-dibutyl cyclopentane 182 C13H26 63.20 1.1.823 52. 2,2,3-trimethyl decane 184 C13H28 64.80 1.1.734 53 2,2-dimethyl undecane 184 C13H28 65.88 2.2.022 54 2,2,6-trimethyl decane 184 C13H28 67.92 2.2.168 55 2,2,9trimethyl decane 184 C13H28 68.06 2.2.021 56 1-fluoro dodecane 188 C12H25F 68.88 1.1.922 57 Cyclohexyl cyclooctane 194 C14H26 70.41 2.2.010 58 2-azido-2,4,4,6,6-pentamethyl heptanes 211 C12H25N3 71.81 1.1.945 59 3-n-hexylthiolane s,s,dioxide 204 C10H20O2S 72.65 0.0.060 60 Trifluoroacetyl-di-tbutylphosphine 242 C10H18F3OP 74.78 1.1.824 61 2,2-dimethyl-propyl-2,2dimethyl-propanesulfinyl sulfone 254 C10H22O3S2 76.06 0.0.945 62 2-methyl-1-octadecene 266 C19H38 78.78 1.1.399 63 Dichloroacetic acid, 6- 268 C12H22Cl2O2 83.56 1.1.623 Ethyl-3-octyl ester 64 3,7,11,15-tetramethyl-2hexadecene 280 C20H46 84.20 1.1.499 65 5-(7a-isopropenyl-4,5-dimethyl octahydroinden-4-yl)-3-methyl pent-2-en-1-ol 290 C20H34O 86.59 NN/Q 66 1-hexacosene 364 C26H52 87.71 1.1.487 67 Eicosyl-cyclohexane 364 C26H52 89.50 1.1.399 68 Baccharane 414 C30H54 89.68 511.151 69 Hexatriacontane 506 C36H74 92.52 0.0.906 70 Tetracontane 562 C40H82 95.56 0.0.729 71 Etratetracontane 618 C44H90 100.75 0.0.028 72 Tetrapentacontane 758 C54H110 103.78 0.0.013 Key: N/Q Not Quantified. Table 3.0: Saturated hydrocarbons identified in the maltene fraction of the bitumen. S/N Compound name Mol. Weight Mol. formula Conc.%(w/w) 1. 3,3-dimethyl pentane 100 C7H16 1.831 2. 3-methyl hexane 100 C7H16 1.529 3. 3,4-dimethyl hexane 114 C8H18 1.723 4. 4-methyl heptanes 114 C8H18 1.847 5. 2,3,4-trmethyl pentane 114 C8H18 1.688 6. 2-methyl heptanes 114 C8H18 1.745 7. 3-methyl heptanes 114 C8H18 1.735 8. 2,2,4-trimethyl hexane 128 C9H20 1.389 9. 2,3,4-trimethyl hexane 128 C9H20 1.351 10 3-methyl octane 128 C9H20 1.268 11. 2,3,3-trimethyl octane 140 C11H24 1.602 12. 2,2,4,6,6-pentamethyl heptanes 170 C11H24 2..048 13. 2,2 dimethyl undecane 184 C13H28 2.022 14. 2,2,9-trimethyl decane 184 C13H28 2.021 15 2,2,3-trimethyl decane 184 C13H28 0.964 16 2,2,6-trimethyl decane 184 C13H28 2.168 17. Hexatriacontane 506 C36H74 0.906 18 Tetracontane 562 C40H82 0.729 19. Tetratetracontane 618 C44H90 0.028 20. Tetrapentanecontane 758 C54H110 0.013 Total % composition 28.61% Table 4.0: Unsaturated hydrocarbons identified in the maltene fraction of borehole bitumen S/N Compound name Mol. Weight Mol. formula Conc. %(w/w) 1. 3-propyl cyclohexane 124 C9H16 1.735 2. 2-pentyl-1-heptene 168 C12H24 1.821 3. 2-methyl-1-octadecene 266 C19H38 1.399 4. 1-hexacosene 364 C26H52 1.487 Total % composition 6.44% Alicyclic compounds or cycloparaffins Alicyclic compounds identified in the deposit were predominantly methyl derivatives of cyclopentane and cyclohexane (Table 5.0). These were very similar to alicyclic hydrocarbons associated with conventional crude oil. The deposit contained relatively low percentages of bicyclic and tetracyclic (baccharane) compounds. The concentration of the alicyclic compounds of the deposits can be used to assess their maturation level. The tetra and pentacycloalkanes are most abundant in young crude oil that is not yet fully developed (Kinghorn.1983). Since these compounds were not predominant in the bitumen sample analysed, the deposit can be said to have reasonably mature for exploitation. These constituents of the deposits could also be subjected to further cracking to yield straight-chain alkanes. Table 5.0: Alicyclic hydrocarbons identified in the maltene fraction of borehole bitumen S/N Compound name Mol. Weight Mol. Formula Conc.%(w/w) 1 Methyl cyclopentane 84 C6H12 0.016 2 Cyclohexane 84 C6H12 0.019 3 1, 1-dimethyl cyclopentane 98 C7H14 0.169 4 1,3-dimethyl-cis-cyclopentane 98 C7H14 1.664 5 1,3-dimethyl cyclopentane 98 C7H14 0.179 6 1,2-dimethyl-cis-cyclopentane 98 C7H14 1.253 7 Methyl cyclohexane 98 C7H14 1.393 8 3,3-dimethyl pentane 100 C7H16 1.831 9. 1,2,3-trimethylcyclopentane 112 C8H16 2.768 10 1,2,4-trimethylcyclopentane 112 C8H16 2.597 11. 1,4-dimethyl–cis-cyclohexane 112 C8H16 2.050 12 1,4-dimethyl cyclohexane 112 C8H16 N/Q 13 1,1-dimethylcyclohexane 112 C8H16 2.196 14. 1-ethyl-3-methyl cyclopentane 112 C8H16 1.891 15. I-ethyl-1-methyyl cyclopentane 112 C8H16 2.779 16. 1,2-dimethyl-trans cyclohexane 112 C8H16 1.939 17. 1,4-dimethyl-trans-cyclohexane 112 C8H16 1.732 18. 1,2-dimethyl-cis-cyclohexane 112 C8H16 N/Q 19 Ethyl cyclohexane 112 C8H16 2.081 20. 1,1,4-trimethyl cyclohexane 114 C9H18 1.796 21. Trans-1,2-diethyl cyclopentane 126 C9H18 1.411 22. 1-ethyl-2-methyl-cis-cyclohexane 126 C9H18 1.821 23. 1,2ß,3–trimethyl cyclohexane 126 C9H18 1.749 24. 1,2,3–trimethyl cyclohexane 126 C9H18 N/Q 25. 1-ethyl-4-methyl cyclohexane 126 C9H18 1.389 26 Methyl cyclooctane 126 C9H18 1.598 27. 1,2,4-trimethyl cyclohexane 126 C9H18 1.690 28 Pentyl cyclopentane 140 C10H20 1.351 29 1,2-dibutyl cyclopentane 182 C13H26 1.823 30. Cyclohexyl cyclooctane 194 C14H26 2.010 31 Eicosyl cyclohexane 364 C26H52 1.399 Total % composition 44.59% Monoaromatic compounds. The monoaromatic compounds identified in the maltene constituents of the bitumen samples were benzene, toluene, ethylbenzene, P-xylene (Tables 6.0), These compounds were similar to aromatic constituents of crude oil (Kinghorn, 1983). The percentage composition of aromatic compounds in the samples was 3.47%.. This value was comparatively lower than the percentage composition of saturated hydrocarbon in the sample. Hence, the ratio of aromatic hydrocarbon to the saturated hydrocarbon was low i.e saturated hydrocarbon present in the sample was in sevenfold of its aromatic counterpart. The decrease in this ratio had been attributed to increasing maturation due to thermal cracking and generation of aliphatic hydrocarbon as compared with aromatic hydrocarbon during thermal maturation (Kinghorn, 1983). The aromatic fraction obtained fron the column chromatography of the maltene fraction of the sample was analyzed for polyaromatic compounds with gas chromatograph. This work was reported elsewhere. Table 6.0: Monoaromatic hydrocarbons identified in the maltene fraction of borehole bitumen S/N Compound name Mol. Weight Mol. Formula Conc.% 1. Benzene 78 C6H6 0.009 2. Toluene 92 C7H8 0.138 3. Ethyl benzene 106 C8H10 1.530 4. P-xylene 106 C8H10 1.793 Total % composition 3.47% NSO compounds and other heteroatomic compounds (Polar compounds) These are compounds containing Nitrogen, Sulphur and Oxygen. These and other heteroatomic co mpounds containing chlorine, fluorine and phosphorus were identified in the maltene portion of the bitumen sample. Nitrogen containing compounds. Percentage composition of nitrogen compounds in the analyzed sample was found to be 3.241% of the sample. Nitrogen compounds are unwelcome in any crude oil, as they are responsible for catalyst poisoning and formation of gum in fuel (Seifet, 1969). Consequently, it is necessary that these nitrogen containing compounds are removed or chemically modified to other compounds that will not pose threat to refining process. Usually, nitrogen containing compounds in crude oil are dislodged of their nitrogen content by hydrodenitrogenation (Eq.2.0) process as follows: H2 N H2 N H2 C5H11NH2 C5H12 + NH3 (2.0) H Sulphur containing compounds. The sulphur compounds are given in Tables (7.0) The percentage composition of sulphur N compounds in the samples was 1.95% of the total deasphaltened oil. The presence of sulphur inHcrude oil is not desirous, since it influences the colour, odour, stability and processing of the crude oil adversely (Oderinde, 1989). All sulphur compounds are foul-smelling and lachrymatory. In addition, these compounds can give poisonous and obnoxious compounds in the refined products, hence making the products corrosive and dangerous to end-users. (Gruse and Steven, 1960.) Sulphur containing compounds could be desulphurized by subjecting them to high – pressure hydrogenation process (Eq. 3.0) high pressure R2S + 2H2 2RH +H2S (3.0) Oxygen, fluorine and chlorine containing compounds. The oxygen containing compounds identified in the samples were predominantly acids, alcohols, aldehydes and esters, these constituted about 4.77% of the total deasphaltened oil. The fluorine containing compounds of the sample constituted about 3.23% of the oil. Table 7.0: The polar compounds identified in the maltene fraction of borehole bitumen S/N Compound name Mol. Weight Mol. Formula Conc.%(w/w) Nitrogen containing compounds 1 Methane isocyanato 57 C2H3NO 0.008 2 3-ethyl-3-hexanamine 129 C8H19N 1.288 3 2-azido-2,4,4,6,6-pentamethyl heptanes 211 C12H125N 1.945 Sulphur containing compounds 4 Trans-2,4-dimethyl thiane S,S dioxide 162 C7H14O2S N/Q 5 6 2-n-propylthiolane,S,S dioxide 3-n-hexylthiolane S,S dioxide 162 204 C7H14O2S C10H20O2S 0.949 0.060 7 2, 2-dimethyl propyl 2, 2-dimethyl 254 C10H22O3S2 0.945 propane sulfinyl sulfone. Oxygen containing compounds 8 2-(1,1-dimethyl ethyl)-3- methyl oxirane 114 C7H14O 1.624 9 2-ethyl-hexanal 128 C8H116O 1.523 10. Dichloroacetic acid, 6-ethyl-3-octyl ester 268 C12H22Cl2O2 1.623 11 290 C20H34O N /Q 5-(7a-isopropendyl-4,5-dimethyl octahydroinden -4-yl)-3-methyl pent-2-en-1-ol Fluorine containing compounds 12 1-Fluoro-dodecane 186 C12H125F 1.922 13. Trifluoroacetyl-di-t-butyl phosphine 242 C10H118F3OP 1.824 Total % composition 13.71% The various chemical compounds identified in the bitumen sample were categorized into their respective refinery products as shown in Table (8.0) Table 8.0: The posssible refinery products obtainable from the bitumen exudate Hydrocarbon Refinery products Uses C7 - C11 Gasoline Fuel for internal combustion engines C11- C Kerosene For lighting purposes and jet fuels. C15- C25 Gas-oil Diesel fuel C22 – C40 Lubricating –oil Grease and wax for automobile engines. Above C40 Asphalt Furnace oil, road asphalt, binder, fillers and water-insulating water. Alkenes (Olefins) Petrochemicals Feed stocks for chemical industries. These compounds are used for the production of synthetic fibre and rubber, plastic, soaps, detergents, paints, drugs and cosmetics Alkanes: Aromatics: C6H6 (Benzene) Basic feed stock required Agrochemicals, dyestuff and pharmaceutical in the production of Linear Alkyl Benzene (LAB) and the production of basic chemical in industries Linear Alkyl Benzene Heavy alkylate Transformer oil, Special grease and- viscous thermal fluid. As an additive in the manufacture of lube-oil. (NNPC,)Solvent makingHerbicides Toluene Chlorotoluenes: Dye stuff industry O-chlorotoluene Raw material for terephthalic acid and dimethyl terephthalate P-Chlorobenzena P-Chlorobenzaldehyde Xylene P-xylene Conclusion The characterization of the maltene fraction of bitumen samples from Odigbo Local government area of Ondo State by GC-MS has been accomplished. The work revealed that chemical compositions of bitumen are very similar to those identifiable in the conventional crude oil. Despite the close similarities in their chemical compositions, the proportion of these compounds in the bitumen exudate actually made it impossible to group it either as paraffinic or naphthenic type of crude oil . For any crude oil to be paraffinic in- nature, the saturated hydrocarbon must be more than 50% and the sulphur content must be less than 1% of the total crude oil (Table 1.0). In the same vein, for a crude oil to be considered naphthenic, its aromatic component must be less than its alicylic counterparts and its sulphur content must be less than 1% . Based upon the classification method employed, the bitumen exudate under investigation has saturated and alicylic hydrocarbons of less than 50% and sulphur content higher than 1%, hence, it can conveniently be classified as asphaltic crude oil. This implies that the bitumen deposit may not be a suitable alternative source of gasoline grade crude oil due to its higher sulphur content which is beyond the range of value (0.2 - 0.5% ) expected for a prospective gasoline grade crude oi (Speight, 1980). Nevertheless, the bitumen contains other valuable chemical compounds that are potential feedstocks for petrochemical industries. Figure 1.0: Gas chromatogram of maltene component of borehole bitumen at Agbabu References. Adegoke, O.S.,Omatsola, M.E and Coker, J.L . 1991.The geology of the Nigerian Tar saands. In: Heavy crude and tar sands hydrocarbonns for the 21st century. Proc. 5th UNITAR Int. Conf. on Heavy Crude and Tar sands pp.369 - 835 Allinson, J.P. 1975: Criteria for quality of petroleum products. Applied Science Publisher, Barking Essex,England. 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