Full Text
Chemistry
Academician A. V. TOPCHIEV, GU QI-WEI, and I. A. MUSAEV
INVESTIGATION OF n-PARAFFIN HYDROCARBONS OF THE KEROSENE FRACTION OF KARAMAI PETROLEUM (CHINA)
In connection with the rapid development of the organic-synthesis industry, the study of petroleum hydrocarbons is acquiring urgent importance. The content of n-paraffin hydrocarbons in petroleum is sufficiently high; they may serve as potential raw material for the synthesis of higher alcohols and other organic intermediates. One of the methods by which n-paraffin hydrocarbons can be isolated from petroleum fractions is the urea method, which has been widely and thoroughly investigated (1–13). In recent years many investigators have applied the urea method to the isolation of n-paraffin hydrocarbons from the kerosene–gas-oil fraction of petroleum. In combination with rectification, the authors succeeded in isolating n-paraffin hydrocarbons of a high degree of purity (90–99 mole %) (14–19).
In the present investigation, the urea method and vacuum distillation were adopted for the quantitative determination of n-paraffin hydrocarbons entering into the composition of the kerosene fraction (175–300°) of the Karamai petroleum of China. The Karamai petroleum was sampled directly from Triassic deposits from well No. 15 at a depth of 549 m.
For the purpose of obtaining the kerosene fraction (175–300°) in unchanged form, the petroleum was first subjected to removal of gasoline on a single-evaporation unit, where the fraction boiling up to 175° was removed; then the gasoline-free portion of the petroleum was subjected successively to deasphalting and deresining by the method of M. A. Kapelyushnikova and T. P. Zhuze (23). The gasoline-free, deresined, and deasphalted portion of the petroleum was distilled in a vacuum unit; the kerosene (175–300°) and gas-oil (300–350°) fractions were thereby collected.
Aromatic hydrocarbons were isolated from the kerosene fraction by adsorption chromatography on ASM-grade silica gel with a grain size of 80–200 mesh in a three-meter two-stage column. The properties of the kerosene fraction and of the aromatic and naphthene-paraffin portions isolated from it are given in Table 1.
Table 1
Characteristics of the kerosene fraction and of the aromatic and naphthene-paraffin portions
| Fraction | $n_D^{20}$ | $d_4^{20}$ | Iodine number | Mol. wt. | Pour point, °C | Aniline point max., °C | Fraction content, wt. %, based on kerosene | Fraction content, wt. %, based on petroleum |
|---|---|---|---|---|---|---|---|---|
| Kerosene 175–300° | 1.4557 | 0.8212 | 6.2 | 198 | −62 | 73.0 | 100 | 15.2 |
| Aromatic | 1.5257 | 0.9244 | 34.0 | 185 | — | — | 10.2* | 1.55 |
| Naphthene-paraffin | 1.4468 | 0.8078 | 1.0 | 205 | −66 | 78.7 | 88.2* | 13.4 |
* In chromatographic separation, the intermediate fraction and losses amount to 1.6% based on kerosene.
Subsequently, the naphthene–paraffin portion of the kerosene fraction was treated with solid urea under the following conditions. Into a round-bottom flask with a metal stirrer were placed 1 kg of urea, 150 g of distilled methyl alcohol, 300 ml of isooctane, and 1 kg of the naphthene–paraffin fraction. The mixture was stirred vigorously for 1 hour. After this, the urea complex that had formed was filtered off, pressed, and washed three times with isooctane saturated with urea.
Fig. 1. 1 — $d_4^{20}$; 2 — $n_D^{20}$; 3 — boiling point; 4 — maximum aniline point; 5 — initial crystallization temperature
The resulting complex was decomposed in a separatory funnel with hot water. The upper hydrocarbon layer was separated and dried with calcium chloride. After removal of the solvents, the hydrocarbons, which had a yellowish color, were purified through silica gel ASM (80–200 mesh).
Thus, from 4015 g of the naphthene–paraffin portion of the kerosene fraction, 269.6 g of a mixture of n-paraffinic hydrocarbons was isolated, the properties of which are given in Table 2.
Table 2
| Fractions | $n_D^{20}$ | $d_4^{20}$ | Mol. wt. | Aniline point max., °C | Solid. temp., °C | Qualitative reaction* | Content of fraction, wt. % on naphthene–paraffin | Content of fraction, wt. % on kerosene | Content of fraction, wt. % on crude oil |
|---|---|---|---|---|---|---|---|---|---|
| Mixture of n-paraffinic hydrocarbons | 1.4262 | 0.7578 | 204 | 86.3 | −16.5 | -- | 6.7 | 5.9 | 0.90 |
| Naphthene–isoparaffinic hydrocarbons | 1.4475 | 0.8088 | 199 | 77.5 | −72 and lower | neg. | 93.3 | 82.2 | 12.5 |
* The qualitative reaction was carried out with a saturated solution of urea in methanol.
For the purpose of isolating individual n-paraffinic hydrocarbons, the mixture of n-paraffins was distilled at 10 mm in a rectification column (140 × 14 mm) with an efficiency of 100 t.t. The distillation curve and the characteristics of the fractions obtained in this process are shown in Fig. 1 and in Table 3.
Table 3
Results of distillation of a mixture of n-paraffins isolated from the petroleum-paraffin portion of the kerosene fraction (mixture of n-paraffins C₁₉—C₂₂, m.p. 38.5—39.5°, \(n_D^{40}\) 1.4368)
| No. | Fractions | B.p., °C/10 mm, exp. | B.p., °C/10 mm, lit. data (20) | Fraction yield, g | Fraction yield, wt. % of mixture of n-paraffins | Fraction yield, wt. % of kerosene | \(n_D^{20}\), exp. | \(n_D^{20}\), lit. data (21) | \(d_4^{20}\), exp. | \(d_4^{20}\), lit. data (21) | Aniline point max., °C, exp. | Aniline point max., °C, lit. data (21) | Initial crystallization temperature, °C, exp. | Initial crystallization temperature, °C, lit. data (21) | Degree of purity,* mol. % | Reaction to iso-paraffins** |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Intermediate | −57.4 | 0.55 | 0.28 | 0.0165 | 1.4160 | — | — | + | |||||||
| 2 | C₁₀ | 57.4—57.6 | — | 7.90 | 4.00 | 0.236 | 1.4121 | 1.4118 | 0.7303 | 0.7299 | 76.8 | 77.5 | −29.7 | −29.67 | 97.2 | − |
| 3 | Intermediate | 57.6—74.7 | 6.25 | 3.16 | 0.187 | 1.4180 | 0.7430 | 78.7 | −32.2 | + | ||||||
| 4 | C₁₁ | 74.7—74.9 | 75.0 | 21.10 | 10.69 | 0.630 | 1.4173 | 1.4172 | 0.7407 | 0.7402 | 80.4 | 80.6 | −25.5 | −25.65 | 99.2 | − |
| 5 | Intermediate | 74.9—91.6 | 5.30 | 2.68 | 0.158 | 1.4228 | 0.7523 | 81.3 | −24.0 | + | ||||||
| 6 | C₁₂ | 91.6—91.7 | 91.6 | 32.50 | 16.46 | 0.971 | 1.4218 | 1.4216 | 0.7491 | 0.7487 | 83.4 | 83.7 | −9.5 | −9.60 | 96.9 | − |
| 7 | Intermediate | 91.7—106.8 | 8.40 | 4.26 | 0.252 | 1.4275 | 0.7623 | 84.0 | −20.4 | + | ||||||
| 8 | C₁₃ | 106.8—106.9 | 106.8 | 33.50 | 16.97 | 1.002 | 1.4257 | 1.4255 | 0.7562 | 0.7562 | 86.4 | 87.0 | −5.3 | −6.0 | 98.9 | − |
| 9 | Intermediate | 106.9—117.4 | 5.17 | 2.62 | 0.155 | 1.4300 | 0.7663 | 86.0 | −16.0 | + | ||||||
| 10 | Intermediate | 117.4—121.4 | 4.50 | 2.28 | 0.135 | 1.4298 | 0.7656 | 88.7 | −2.1 | + | ||||||
| 11 | C₁₄ | 121.4—121.4 | 121.5 | 17.55 | 9.14 | 0.540 | 1.4291 | 1.4291 | 0.7637 | 0.7626 | 88.8 | 89.5 | +5.6 | +5.5 | 91.7 | + |
| 12 | C₁₄ | 121.4—121.6 | 121.5 | 4.33 | 2.19 | 0.129 | 1.4297 | 1.4291 | 0.7644 | 0.7626 | 88.6 | 89.5 | +5.4 | +5.5 | 94.6 | + |
| 13 | Intermediate | 121.6—128.7 | 4.12 | 2.08 | 0.123 | 1.4342 | 0.7763 | 86.5 | −7.2 | + | ||||||
| 14 | Intermediate | 128.7—133.9 | 4.22 | 2.14 | 0.126 | 1.4332 | 0.7726 | 90.5 | −11.9 | + | ||||||
| 15 | C₁₅ | 133.9—134.4 | 135.5 | 9.18 | 4.65 | 0.275 | 1.4327 | 1.4319 | 0.7705 | 0.7683 | 91.0 | 92 | +8.2 | +9.81 | 91.3 | + |
| 16 | Intermediate | 134.4—142.3 | 4.00 | 2.02 | 0.119 | 1.4362 | 0.7805 | 88.5 | −3.1 | + | ||||||
| 17 | Intermediate | 142.3—144.0 | 4.09 | 2.07 | 0.122 | 1.4359 | 0.7786 | 92.2 | −6.2 | + | ||||||
| 18 | C₁₆ | 144.0—146.7 | 148.7 | 4.07 | 2.06 | 0.122 | 1.4358 | 1.4345 | 0.7772 | 0.7734 | 93.4 | 95 | +14.1 | +18.15 | ∼84 | + |
| 19 | — | 146.7—156.6 | 6.35 | 3.22 | 0.190 | 1.4387 | 0.7851 | 91.7 | +2.1 | + | ||||||
| 20 | — | 156.6—159.5 | 4.94 | 2.50 | 0.148 | 1.4388 | 0.7840 | 94.6 | +12.9 | + | ||||||
| 21 | — | 159.5—168.5 | 3.56 | 1.80 | 0.106 | 1.4409 | 0.7899 | 93.4 | +12.6 | + | ||||||
| Residue | 45.20 | 1.4367 | m.p. 37.5—38.7 °C | |||||||||||||
| Losses | 3.27 |
* The degree of purity of the n-paraffinic hydrocarbons was determined by N. I. Lyashkevich.
** A plus denotes the presence of a hydrocarbon with a tertiary carbon atom; a minus denotes its absence.
The individual \(n\)-paraffinic hydrocarbons obtained have a purity of 91–99 mole %, with the exception of hexadecane.
From Fig. 1 and Table 3 it is evident that the mixture of \(n\)-paraffinic hydrocarbons isolated with the aid of solid urea from the naphthene-paraffin portion of the kerosene consists of 66% paraffinic hydrocarbons of normal structure and 31% hydrocarbons of iso-structure, which are concentrated in the intermediate fractions.
The contents of the individual \(n\)-paraffinic hydrocarbons differ greatly from one another. They are distributed in the kerosene fraction (175–300°) as follows (in %): \(C_{10}\) 0.24, \(C_{11}\) 0.63, \(C_{12}\) 0.97, \(C_{13}\) 1.00, \(C_{14}\) 0.67, \(C_{15}\) 0.27, \(C_{16}\) 0.12. Dodecane and tridecane constitute 50% of the sum of all \(n\)-paraffins, while decane and hexadecane constitute only 6 and 3%, respectively.
Institute of Petrochemical Synthesis
Academy of Sciences of the USSR
Received
14 VII 1960
CITED LITERATURE
- F. Bengen, W. Schlenk, Experientia, 5, 200 (1949); Chem. Abstr., 44, 1910 (1950).
- W. J. Zimmerschied, R. A. Dinerstein et al., Ind. and Eng. Chem., 42, 1300 (1950); J. Am. Chem. Soc., 71, 2947 (1949).
- O. Redlich, C. M. Gable et al., J. Am. Chem. Soc., 72, 4153 (1950).
- R. W. Schessler, D. Flitter, J. Am. Chem. Soc., 74, 1720 (1952).
- B. T. Bruks et al., Khimiya uglevodorodov nefti, 1, Izd. IL, 1958, p. 202.
- L. M. Rozenberg, I. S. Genekh, 84, No. 3, 523 (1952).
- A. V. Topchiev, L. M. Rozenberg et al., DAN, 98, No. 2, 223 (1954).
- L. M. Rozenberg, E. M. Terent’eva et al., DAN, 109, No. 6, 1144 (1956).
- Composition and Properties of the High-Molecular-Weight Part of Petroleum, Moscow, 1958, p. 208.
- I. Krachevskii, G. Efremova, T. Leont’eva, DAN, 113, No. 4, 817 (1957).
- I. Gurevich, Van Chung-lan et al., Khim. i tekhnol. topliva i masel, No. 8, 56 (1957).
- B. Klimenok, M. Bondarenko et al., Collection of Papers, Ufa Petroleum Institute, issue 2, 195 (1958).
- K. Kraft, Chem. Abstr., 52, 11396 (1958).
- Kh. Arshidze, E. Benashvili, DAN, 110, No. 3, 387 (1956).
- A. V. Topchiev, S. S. Nifontova et al., DAN, 111, No. 6, 1045 (1956).
- V. G. Nikolaeva, E. V. Zvereva, Khim. i tekhnol. topliva i masel, No. 3, 11 (1956).
- L. M. Rozenberg, A. V. Topchiev, DAN, 122, No. 4, 621 (1958).
- F. D. Rossini, The Chemistry of Hydrocarbons of Petroleum, IL, 1957.
- B. J. Mair, W. J. Marculaitis, F. D. Rossini, Anal. Chem., 29, No. 1, 92 (1957).
- M. D. Tilicheev, A. V. Iogansen, ZhFKh, 24, No. 7, 770 (1950).
- R. D. Obolentsev, Physicochemical Constants of Hydrocarbons of Liquid Fuels and Oils, 1953.
- L. M. Rozenberg, E. M. Terent’eva, Izv. AN SSSR, OKhN, 1959, No. 3, 285.
- T. P. Zhuze, Vestn. AN SSSR, No. 11, 47 (1959).