General Remarks. Part 9
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This section is from the book "Distillation Principles And Processes", by Sydney Young. Also available from Amazon: Distillation Principles And Processes.
General Remarks. Part 9
Pentamethylene In Petroleum
In a similar manner, it was found that there is a small quantity of pentamethylene (and also trimethyl-ethyl-methane) in American petroleum.
The first fractionation of all the available distillates from petroleum ether obtained with the combined bubbling and regulated temperature still-heads, and collected between about 37° and 60°, gave no indication of the presence of any substance boiling in the neighbourhood of 50°, as will be seen by Table 80.
1 Fortey, " Hexamethylene from American and Galician Petroleum," Trans. Chem. Soc, 1898, 73, 103.
2 Young and Fortey, "The Vapour Pressures, Specific Volumes, and Critical Constants of Hexamethylene," ibid., 1899, 75, 873.
3 Young, loc. cit.
Table 80
I. | II. | IV. | VII. | ||||
Temperature range. | | Temperature range. | | Temperature range. | | Temperature range. | |
36 - 37° | 47.4 | 36 - 37° | 47.8 | 36.8 - 42 0° | 5.0 | 45.0 - 49.35° | 3.8 |
37 - 40 | 22.2 | 37 - 39 | 11 8 | 42.0 - 47-7 | 3.1 | 49.35 - 50-1 | 34 9 |
40 - 45 | 3.1 | 39 - 42 | 5.9 | 47.7 - 50-7 | 12.9 | 50.1 - 51.3 | 16.0 |
45 - 50 | 6.2 | 42 - 47 | 4.0 | 50.7 - 53-4 | 12..6 | 51.3 - 53.7 | 6.7 |
50 - 54 | 12.2 | 47 - 51 | 6.0 | 53.4 - 56-2 | 7.8 | ||
54 - 57.5 | 22.6 | 51 - 54 | 16.5 | 56.2 - 58-6 | 10.3 | ||
57.5 - 59.5 | 24..7 | 54 - 57 | 14.4 | 58.6 - 59-6 | 15.7 | ||
59.5 - 60.4 | 39.0 | 57 - 59.2 | 17..8 | ||||
59.2 - 60-1 | 38.9 |
Temperature range. | | | Specific gravity at0°/4°. |
47.3 - 49.45° | 11.5 | 5.3 | 0.7029 |
49.45 - 9-55 | 16.3 | 163.0 | 0.7035 |
49.55 - 50-35 | 160 | 20.0 | 0.6975 |
50.35 - 56-4 | 150 | 2.5 | . |
In the second distillation, however, the value of for the traction 51 - 54' was slightly higher than lor the one above and much higher than for that below it.
In the fourth fractionation the maximum was quite clearly defined, and the value of near 50° steadily increased in the subsequent operations, rising from 12.9 in the fourth to 34.9 in the seventh and 48.0 in the ninth.
The quantity of material was too small to allow of the separation being continued with the combined bubbling and regulated temperature still-heads, but six additional fractionations were carried out with a 12-column bubbling still-head, when the value of rose to 163.0 for the fraction from 49.45° to 49.55°.
The distillate, amounting to 16.3 grams, was found to yield glutaric acid on oxidation with nitric acid, and therefore contained penta-methylene. The specific gravity, 0.7035 at 0°/4° was, however, too low and the vapour density, 39.2, too high for pure pentamethylene (sp. gr. 0.751 at 15°/15°; vap. den. 35). As the calculated vapour density of hexane is 43, it would appear that the distillate consisted of a mixture of pentamethylene and trimethyl-ethyl-methane in approximately equal molecular proportions. The results are quite in accordance with those obtained by Markownikoff,1 who showed that both these hydrocarbons are present in Russian petroleum, the quantity of pentamethylene and other naphthenes as compared with that of the paraffins being, however, much larger in Russian than in American petroleum.
1 Markownikoff, "On Cyclic Compounds," Liebig's Annalen, 1898, 301, 154.
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