Nitrogen compounds in high-boiling and residual products of West-Siberian crude oil

Petrol. Chem. U,S.S.R. Vol. 26, No. 3, pp. 123-136, 1986 Printed in Poland

0031--645 8186 $I0.00+ .00 © 198"/Pergamon Journals Ltd.

NITROGEN C O M P O U N D S IN HIGH-BOILING AND RESIDUAL P R O D U C T S OF WEST-SIBERIAN CRUDE OIL* V. KISELEV, D. BODZEK, V. KERNBAKH and L. VAZHEKHA Institute of Petroleum and Coal Chemistry, Polish Academy of Sciences, Gliwice, Poland (Received 8 October I 985)

THIS paper is aimed at investigating the group and individual composition of organic nitrogen compounds (NC) and their distribution in high-boiling and residual products of West Siberian crude oil of Samotlor type. INTRODUCTION

Ion-exchange chromatography (IEC) was used for separating concentrates of nitrogen compotmds from the products examined. Chromatographic columns were ion-exchange resins previously activated: cation-exchange resin (15-Serva Feinbiochemie, German Federal Republic) to isolate main compounds and with anionexchange resin (Amberlite IRA-904-Rohm and Haas Co., U.S.A.), in order to isolate acidic compounds of nitrogen. A solution of t h e sample in cyctohexane (distillate products) or benzene (residual prod~tcts) was introduced into the column and components that do not form complexes were eluated with solvent. Main NC were then eluated stepwise with benzene, methanol mixed with 8 ~o isopropylamine and trichloroethylene. Acidic compounds of nitrogen were eluated with benzene, methanol and trichloroethylene. After the distillation of solvents the eluates were combined and concentrates of basic and acidic compounds of nitrogen obtained. Complex-forming chromatography was used to separate nemral or jointly acidic and neutral NC and to increase the content of nitrogen compounds in concentrates. To isolate neutral (or jointly acidic and neutral) NC, ferrous chloride FeCI3 "6H20 precipitated on an adsorbent (Attaptdgus, Engelhardt Minerals and Chem. Div., U.S.A.) was used as complex-forming phase. The cyclohexane (or anhydrous for residual products) elttate of components tmreacted with ion-exchange resins, was introduced into a column filled with a complex-forming reagent and components that do not form complexes, were eluated with cyclohexane. The complex formed was broken down with ammonia gas and eluated with 1,2-dichloroethane; after distilling off the solvent a concentrate of neutral (or neutral and acidic) compoamds of nitrogen was obtained. For subsequent separation of concentrates, in order to increase the content of nitrogen compounds, tetrachlorophthalimidipropyltriehlorosilane (TPS) combined * Neftekhimiya 26, No. 4, 487--498, 1986. 123

124

V. KIsE[.fiv et ol.

with silica gel was used as complex-limning phase; this phase has etectron-acceplor properties and forms complexes with aromatic hydrocarbons. Separation was carried out using a liquid chromatograph "LDC-Milton Roy" (England) with an UV detector, recording absorption in the range of ).=280 nm. Methylene chloride and N,N-dimethylformamide were used as mobile phase(elutriators). Two fractions were obtained after distilling off solvents: a fraction of increased content of nitrogen compounds and hydrocarbons. Liquid adsorption chromatography was used for determining the group hydrocarbon composition of fractions after isolating concentrates of nitrogen compounds. Sample solutions in n-pentane were introduced into a column filled with silica gel (for the distillate) or alumina (for the residue). Saturated hydrocarbons were eluated with n-heptane (from the distillate) or n-heptane (from the residue) and aromatic h y d r o c a r b o n s - w i t h benzene. Resins were eluated with trichloroethylene. Thin-layer chromatography (TLC) was used to determine the presence of functional groups in concentrates of nitrogen compounds and to define more accurately conclusions regarding IR spectra and the presence of these groups. 20 × 10 cm glass plates coated with a thin (0-25 ram) layer of adsorbent (Kieselgel 60 F254) were used. The plates were activated, heated for 1 hr at 80°C and then for 2 hr at 130'-C. Chromatograms of benzene solutions of samples were recorded in three stages: up to ½, ¼ and at a distance, 16 cm long. A mixture of tetrahydrofuran, benzene and n-hexane (1 : 1 : 1) was used as mobile phase. The presence of functional groups was established using Dragendorff, Wackmeiste,r, Ehrlich developers, bromocresol green and blue salt B. Gel-permeation chromatography (GPC) was used to determine molar mass distribution of concentrates of nitrogen compounds. A chromatograph made by Laboratory Data Control (England) with an UV absorption detector was used in the rangc of 2 =350 nm. Narrow fractions obtained by preparatory chromatography from a mixture of distillation residues of various crude oils were used as stan:lards for establishing the calibration curve. Mass-concentrate distribution curves of compounds were established using computer data. Vapour-phase osmometry was used to determine the average molar mass of concentrates of nitrogen compounds. IR spectrometry was applied to control separation of nitrogen compounds on ion-exchange resins and to determine functional groups. An IF spectrometer with Fourier transform was used (Nicolet Analytical Instruments). Carbon and hydrogen contents were determined by classic elementary analysis, sulphur c o n t e n t - b y combustion in oxygen in the presence of Pt, overall nitrogen c o n t e n t - b y the Dumas method and the Kjeldahl micromethod. The content of basic nitrogen was determined by potentiometric titration with perchloric acid in chlorobenzene and glacial acetic acid. NMR spectrometry was used to determine proton content in structural elements of nitrogen compounds. Spectra were obtained by a Varian EM 360 spectrometer. Hydrogen content was determined using integral carves of spectra.

NC in products of West-Siberian crude oil

125

Mass spectrometry was used for determining the individual composition of concentrates of nitrogen compounds by a method developed by Polyakova [1]. Spectra were obtained on a mass-spectrometer MX-1320 of resolution 10,000 with an ionizing voltage of 50-70 eV. Low resolution mass spectrometry was used for determining molar mass distribution of nitrogen compounds. Spectra were obtained usings Jeol JMS-01SG-2 spectrometer with a computer made by Texas Instr. 979 with an ionizing voltage of 15 eV, the sample being directly introduced into the ionizing chamber with a probe. EXPERIMENTAL

Standard samples of high-boiling fractions and residual products were used, which had been prepared in a semi-industrial plant from a commercial mixture of Samotlor type West-Siberian crude oils. Product samples examined and some of their properties are given in Table 1. A detailed investigation was carried out using chemical

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Fro. 1, Curves of molar mass distribution of concentrates of nitrogen compounds (c) and an asphaltene extract (b), a: concentrate of acidic (1) and basic (2) compounds.

126

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3280

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PROPERTIES

OF

CONCENTRATES

OF

ORGANIC

NITROGEN

COMPOUNDS

E l e m e n t a r y c o m p o s i t i o n , wt. % l n i t i a l product C 350°-540 ° fraction concentrates basic acidic neutral Residue of a t e m p e r a t u r e higher t h a n 540°C concentrates basic acidic neutral Asphaltenes concentrates basic acidic neutral Resins concentrates basic acidic neutral Oils concentrates basic acidic neutral

H

Ntot=l

Nbul=

S

1"72

1"14 0"12 0"19

2"60

0-73 0"27 0"24

2-69 2-66 2"92

----

2-87 2-26 2.59

-2-6 3-5

3"46 3.29 2-68

0.7

3"1 2"6 4"9

456 409 917

80"5 82"9 82"4

9-4

13"9 14"3 17'5

1282 1460 1333

85"5 86"0 84"1

8-8 9-0 8.6

1"45 1 "43

35"7 20"9 24"5

82-6 80"6

6-9 7-7

1"38 1 "55 1"70

21"0 9"0 11"0

83"2 87-2 81.6

7.8 8-9 8.5

1 '54 1 "68 1 "28

5.5 9"0 17"5

79'6

9'9

1"29 1"42 0"88

83"1

10"1

1"65 1"28

1"14

m

m

1-30 3"20

w

4"01

B

2"29 3"6

---

--

-

1"6 3"6 1"2

128

V. KISELEV et al.

100

Basic, [ ~ Acidic 8O

[ ~ Neutral

6O ¢o

\ \ \

\\\

~'3~

H~7~

20

Residae Asphal- Resins 350-5q0°C >SqO°C fanes

Oisfillafe

Oils

FIG. 3. Distribution of concentrates of nitrogen compounds in high-boiling and residual products

o f Samotlor type crude oil.

TABLE 3. PROPERTIES OF FRACTIONS OBTAINED FROM CONCENTRATES OF NITROGEN COMPOUNDS HIGHER THAN 5 4 0 ° C ESTABLISHED CHROMATOGRAPHICALLY ON TETRACHLOROPHTHALIMIDIPROPYLTRICHLOROSILANE

Concentrates of nitrogen compounds Acidic fraction 1 fraction 2 Basic fraction 1 fraction 2

Yield, %

Elementary composition, wt. C H

N

42"5 57"5

82.3 74.6

9.2

0"6

7.8

3"7

36"0

80.8

9.1

64"0

75.6

8.2

1"3 2"8

NC in producls of West-Siberian crude ell

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aL

and physico-chemical methods of concentrates of nitrogen compound~ isolated from products shown in Table I by a method described (by separating the residue above 540°C). General loss in separating the products examined by this method was not higher than 3-5 ,,s Table 2 shows properties of concentrates of nitrogen compounds isolated by ion-exchange and complex-forming chromatography on FeCI3; Table 3 shows properties of enriched concentrates of nitrogen compounds. Enrichment was effected by complex-forming chromatography and liquid chromatography on the electronacceptor phase of TPS. Average molar mass values of concentrates of nitrogen compounds were determined by vapour osmometry. Molar mass distribution was determined by gel-permeation chromatography for concentrates of acidic and basic nitrogen compounds of the residue above 540°C and by mass-spectrometry for asphaltene extracts. An extract with a yield of 25.5~ was obtained by 70 hr extraction of asphaltenes with n-heptane in a Soxhlet apparatus. The molar mass distribution of concentrates of nitrogen compounds is shown in Fig. la and for an asphaltene extract - in Fig. lb. The presence of functional groups in concentrates of nitrogen compounds was determined by thin-layer chromatography and IR-spectra. Figure 2 shows the most typical sections of IR-spectra. Proton distribution in structural elemenls of concentrates of nitrogen compounds was determined using integral curves o f N M R spectra (Table 4). The individual composition of concentrates of nitrogen compounds was determined by high resolution mass-spectrometry for concentrates of basic and acidic NC from 350°-540°C fractions. ,/L~ '

RESULTS

The concentrates isolated are products with an increased content of heterocompounds, a significant part of which are organic and, apparently, also organometallic nitrogen compounds. In addition to nitrogen compounds, concentrates contain sulphur compounds, aromatic hydrocarbons and inorganic components. The presence of the last-named is confirmed by the high ash-content (0-70-3.5 °/ Table 2) of concentrates of nitrogen compounds prepared from resins and asphaltenes, respectively and high contents of Ni and V (Table I). The content of concentrates in the petroleum product increases with a rise in its boiling point and average molar mass (Table 1). It can be seen in Table 1 that the overall content of concentrates is 10"6 ~o of the weight of dis tillate of b.p. 350°-540°C and 45.7 ~ of the vacu um-resid ue above 540°C of Samotlor crude. Even higher percentage of concentrates is contained by group components of the residue, 9/0:asphaltenes 81, resins -41 and oil -32. Nitrogen content in components of the residue increases from 0.37~ N in oils to 1-22% N in asphaltenes (Table 2), respectively. The selectivity of separating group components of nitrogen compounds (basic, acidic and neutral) may be regarded to be satisfactory, considering results of deteri t O~

NC in products of West-Siberian crude oil

131

mining functional groups by TLC and IR-spectra. Concentrates of basic compounds of nitrogen contain no acidic functional groups if basic groups are present (nitrogen in a pyridine ring) and concentrates of acidic compounds of nitrogen contain no basic groups if acidic groups are present (nitrogen in pyrrole ring, phenol group). Acidic and basic functional groups have not been found in the concentrate of neutral nitrogen compounds. IR spectra of concentrates of acidic and basic NC vary considerably in the range of 3400-3700 c m - t . Three absorption bands (Fig. 2) characterize acidic compounds of nitrogen in this spectrum range: 3640-3520 cm -1, corresponding to bond-stretching vibrations of the free hydroxyl group; 35803520 cm -1 and strong bands with a maximum at 3479 cm-1, corresponding to bond-stretching vibrations of hydroxyl groups associated with a hydrogen bond. These absorption bands are absent from spectra of basic NC. It was established from N M R spectra that compared with acidic nitrogen compounds, an average molecule of basic nitrogen compounds contains fewer aromatic protons and protons in position ~ to the aromatic nucleus and more saturated protons in position fl and more protons remote from methylene, methine and methyl groups. This indicates the predominance of saturated structural elements in the concentrate of basic nitrogen compounds. Concentrates of acidic and basic nitrogen compounds from the residue at 540°C contain compounds with a molar mass of 400-4000 amu with the predominance of compounds with mass 800 amu for basic and 600 ainu for acidic nitrogen compounds (Fig. 1). Concentrates of neutral compounds of nitrogen from a 350 to 540°C distillate (917 amtt) and acidic NC from a residue above 540°C (1460 amu) (Table 2) have the highest average molar mass values. The distribution of concentrates of three kinds of NC in group components of the residue at a temperature higher than 540°C (Fig. 3) is very similar from a quality point of view. All the three forms of nitrogen compound are present in all group components of the residue in similar proportions, which proves that separation in relation to nitrogen compounds is a non-selective process. The high concentration of all nitrogen compoands and inorganic components in asphaltenes is clearly evident. The individual composition of multi-component complex mixtures, such as the concentrates of nitrogen compotmds examined, can only be determined by high-resolution mass-spectrometry. A limitation of the method used is the low volatility and complex composition of concentrates in this case; consequently, mass-spectra reflect the composition of a comparatively small part of the product, which could not be determined on the spectrometers used in this study. MS analysis was carried out using concentrates of basic and (acidic+neutral) nitrogen compounds obtained from a 350°-540°C distillate fraction. Basic nitrogen compounds detected in the concentrate, compounds with one nitrogen atom and molar mass values of 170-350 amu correspond to 11 homologolts series ranging from Cnn2n_9N to CnHzn_29N; possible structural formulae of the first members of these homologous series and their molar mass values are as follows:

132

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I :i'_,t [i:,N

/

et td.

177,, I~7, 21~1, '215

,

( .... i/'I h

t, ./i N

C~,H2n-ll N

Ci:,lflgN

213, 227. 241

~" l- i ../\/\,/ N C H2n_l 3 .IN (2lTH21N

239,253, 2(;7

LJ\)..!\)\) N

209,223,237, 25t, 265,279 N

(]ti ~[21t_l 7 N ,

J

/

" '

'"~S\ )

21P7, 22t, 235,249, [ 263,277, 291

N

11 Cr, H2~-Is N ClaHl?N

I

I

.I

I

2~7, 261,275,289,317

I

N

('..ll2r~_21N

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f'\ i - ~ / % _ _ II J :I /i L...'\.d'\d\

(]lSHl;,N

245, 259, 273, 289, 3t7

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C,,.IlI~N

J

J\/"

N

\/J\

285, 299

N

.-'\A/k J\) I 1 CnH 2n-25 N

C2aH..,1N

I

.I

31 t, 325,339

I

~S\O; CnHin-29N

C26H2aN ..,

~

,#~/'k./

349

\ , ( %

L ;/ / \ / \ / f

I

NC in products of West-Siberlan crude oil

133

These compounds contain 12-16 carbon atoms in the molecule, ranging from one to four aromatic rings (condensed or isolated) and from two to four cycloparaffinic rings. Lateral alkyl chains contain two to four carbon atoms. Nitrogen is combined in a pyridine or pyrrolidine ring. NC found in the concentrate (acidic+neutral) with one nitrogen atom and molar mass values of 200-300 amu corr,/spend to nine homologous series ranging from C.H2._llN to CnH2.-27N; possible structural formulae of the first members of these homologous series and their molar masses are as follows:

CnH2n_llN C a 4 H I ; N

~

199, 2i3 Cz

CnH2n_I~N C 1 , H t s N

C,,H2,,_15N CxeHITN

I

H

c~~_..~

t97, 2ii

/fl\/".,/\

223,237,25t N I

tI 22t,235,249,263 N [

H

205,2|9,233,247, 26! N

I

H

CnHo-n-2tN

C~°HIgN

I

273,287

I

I

H

C~H "-'sN

C-"Hx'N '

( /\ ( ~ - \ /- 0 N

I

H

27t,285,299,3t3

V. KISELEVet al.

134

These compounds contain 14-23 carbon atoms in the molecule and one-to-twt~ aromatic rings, condensed with a pyrrole ring and also cycloparaffinic rings and short (up to four C atoms) alkyl chains. Concentrates of basic and (acidic + neutral) " TABLE 4. DETERMINING PROTON DISTRIBUTION BY ~H N M R

Concentrate of components

Proton content (~) in an average molecule A~'o~matic-(H5 in aromaiicand heter0:aromatic rings Saturated (H~) in lateral chains of an aromatic nucleus in position ~ (in methyl, methylene and methine groups) Saturated (Hpcn~cH) in lateral chains of the aromatic nucleus in position fl and more remote positions (in methylene and methine groups) Saturated (Hpc.~) in lateral chains of the aromatic nucleus in position D'and more remote positions (in methyl groups)

22"2

i6"l

23'3

t9'6

37'8

45.4

16.7

18"9

nitrogen compounds also contained compounds, which apart from one nitrogen atom, also contained one sulphur or oxygen atom. These compounds with molar mass values of 200-300 ainu correspond to seven homologous series: CHNS type compounds correspond to series ranging from C,,H2,_ 9NS to C, H2,- 2 1 N S , structural formulae of the first members of the homologous series being as follows: t:~,tl,,,~_vNS ('I,_,tf,:,NS

N\

]IN /]\ ) \

[

21~5,21!1,233,2.~7

S C~H z,L._nNS (;I.,III~NS

N

. ../I\~ s

4"'II'-"a-laNS ¢:':'tt'aNS

/

)

245,259,273,287

N,,

215, 229, 2~'3

.,

. ) ~ / ;[I

P ~

S C.H2n_15NS Clallt?NS

t].[{2n-17NS (:I4lttt NS

:J~'ff\,~-----N

IS5, 311

S ...... .~::"'\~\, ~ N

225,239 S

N

S N

CnH2n-otNS C~HgNS

I

\/ $

235

NC in products of West-Siberian crude oil

135

CHNO type compounds correspond to series ranging from C,H2,_9N0 to C,H,,_,,NO: structural formulae of the first members of the homologous series are as follows: 203 N

0

I-i 201

209,223,237, 251

C,,H,,_,,NO ‘A&NO

277

NO CzOHIgNO %Z%-21

289,303

Compounds contain 12-21 carbon atoms in the molecule and one-or-two aromatic rings condensed with ‘cycloparaffinic or heterocyclic rings. Nitrogen is combined in them in pyridine or thiazole rings, sulphur -in thiazole or thiophen rings, while oxygen - in dihydropyrane rings or a carbonyl group in the ring. In general, in concentrates of nitrogen compounds prepared from a fraction of 350”-540°C 39 basic nitrogen compounds, 22 acidic and neutral nitrogen compounds, 19 compounds containing nitrogen and sulphur and 12 compounds containing nitrogen and oxygen, were identified. Bearing in mind the general regularities in the che-

136

V. Z, SHARF et al.

mical composition of petroleums it may be assumed that homologous series of nitrogen compounds present in a 350~-540°C distillate, are also continued in Samotlor type residual oil products. SUMMARY

1. Distribution of basic, acidic and neutral nitrogen compounds was examined in concentrates from a 350°-540°C distillate, a residue higher than 540°C and group components of the residue (asphaltenes, resins and oils). 2. 39 basic nitrogen copmounds, 22 acidic and neutral compounds, 19 compounds containing nitrogen and sulphur and 12 compounds containing nitrogen and oxygen were identified in a nitrogen compound concentrate from a 350°-540°C fraction. REFERENCES

1. A. A. POLYAKOVA, Molekulyarnyi mass-spektral'nyi analiz organicheskikh soyedinenii (Molar mass-spectral Analysis of Organic Compounds), Khimiya, Moscow, 1983

Petrol, Chem. U.S.S.R. Vol. 26, No. 3, pp. 136-141, 1986 Printed in Poland

0031-6458/86 $10.00+ .00 ~L~1987 Pergamon Journals Ltd,

HYDROGENATION OF PENTA-t,3-DIENE ON PALLADIUM COMPLEXES W1TH MACRO-POROUS ANION-EXCHANGE RESIN S * V. Z. SHARF,L. D. PANFILOVA,L. P. KARAPETYAN and K. M. SALADZE N. D. Zelinskii Institute of Organic Chemistry, U.S.S.R. Academy of Sciences Scientific Research Institute of Plastics (Received 23 December 1985)

COMPLEXESof palladium with gel type ion-exchange resins are active in hydrogenation and isomerization of unsaturated compounds [1 ]. It could be expected that palladium complexes on macro-porous anion-exchange resins with a highly developed surface 1"2] are of high activity and specific action in hydrogen adqlition to unsaturated hydrocarbons. This paper presents a study of the synthesis of palladium complexes with macroporous polyamine and polyvinyl pyridine anion-exchange resins and examines their catalytic properties in hydrogenation of penta-l,3-diene (PD). * Neftekhimiya 26, No. 4, 504-508, 1986.