Straight Carbon Chain Research Articles

An investigation of the products of the recombination of alkyl radicals in the liquid-phase radiolysis of n-hexane

1. 1. The composition of the C 9C 12 fraction of the higher products of the liquid-phase γ-radiolysis of pure n-hexane and n-hexarm containing butylene at +20° and −77° has been studied experimentally. 2. 2. The isomeric composition of the dimeric product of the radiolysis of n-hexane has been studied in detail and some properties of the different hexyl radicals have been elucidated. 3. 3. The relative stationary concentrations of the hexyl radicals have been calculated and it has been shown that the recombination constants of different hexyl radicals with a straight carbon chain are practically equal in the liquid phase. 4. 4. It has been shown that in the liquid-phase radiolysis of n-hexane (at +20 and −77°) thermal H atoms add to the double bond of olefins. A method for evaluating the stationary concentration of thermal H atoms has been proposed. 5. 5. Four isomers of dodecane have been synthesized for the first time and their physical properties have been determined.

The Chemical Constitution of Natural Fats

THE fats constitute a large group of natural substances. They are present in plants and animals on land and water, both salt and fresh; they represent an important ingredient of our food. To the chemist they are compounds of glycerol with fatty acids, long straight-chain carbon compounds in an ascending series of numbers from C14 to C24, increasing by two carbons at a time. Nature has curious devices, eccentric habits; one of them is to ring the changes with relatively few substances, combined together in different ways, so as to produce a vast number of different fats, that is glycerides, characteristic of individual plants and animals. The process is akin to the infinite number of melodies which the pianist can produce on a few notes. The Chemical Constitution of Natural Fats By Prof. T. P. Hilditch. Pp. xi + 438. (London: Chapman and Hall, Ltd., 1940.) 35s. net.

Magnetic Anisotropy of Diphenyldiacetylene

E. H. WIEBENGA has recently determined the crystal structure of diphenyldiacetylene1, (C6H5).C:C.C:C.(C6H5). The molecule is plane, with a straight carbon chain, the length of the molecule making angles of approximately 48°, 52°, 78° with the a,b,c axes of the monoclinic unit cell. (By inadvertence, the complements of the first two angles were given in Dr. Wiebenga's letter in NATURE. He has since very kindly sent me the exact direction cosines determined by means of a Fourier analysis, and has also provided me with some beautiful crystals for this investigation.)

The structure of surface films XXI—Surface potentials of dibasic esters, alcohols, aldoximes, and ketones

The object of this work was to obtain further information on several points affecting the dependence of surface potentials of unimolecular films on water surfaces, on the constitution and orientation of the molecules in the films. Measurements on the dibasic esters were expected to throw light on the relation between surface potential and density of packing of molecules in films of “gaseous” type; the measurements on alcohols, aldoximes, and methyl ketones were undertaken primarily in order to obtain values for the surface potential produced by the polar groups in these compounds, which could be compared with the potentials found with derivatives of the sterols, in which the same polar groups are attached to a complex ring system, instead of to an aliphatic straight carbon chain. The surface potential ΔV is the change in contact potential between the aqueous solution on which the film is spread, and air, caused by the presence of the surface film. The simplest basis of comparison is the quantity μ given by the equation ΔV = 4π n μ, n being the number of molecules per square centimetre of the films. If the dipoles of the film molecules were arranged as a parallel plate condenser in the surface, Kμ cos θ would be the dipole moment of the molecules, θ being the angle at which these dipoles are inclined to the vertical, and K the dielectric constant of the surface film. θ is in general unknown; but by comparsion of the highest values of μ obtained, with the values for the dipole moments of various polar groups in organic molecules obtained by other methods, it may be concluded that the value of K in the surface films is usually of the order 5 to 10.

Raman Spectra of a Series of Octanols

The Raman spectra of a series of nineteen octanols were obtained using Hg 4358 as the exciting line. These alcohols have structures which differ only in the relative position of a C${\mathrm{H}}_{3}$ and OH group along the side of a straight carbon chain seven atoms long. The Raman spectra consist in most cases of from seven to ten modified lines whose position and intensity vary considerably for the different compounds. A comparison of the Raman spectra and the molecular structure leads to an interpretation of most of the modified lines in terms of modes of vibration of the molecules. The lines which have been accounted for appear to be due to vibrations of the type C-H, C${\mathrm{H}}_{3}$-X, OH-X, and a C-C vibration in a plane at right angles to the length of the chain.

The Anesthetic Properties of Certain Unsaturated Ethers.

From a general consideration of the chemo-pharmacological properties of di-ethyl ether and ethylene, especially in regard to their marked anesthetic power and relatively low toxicity, it seemed possible to predict that compounds combining the chemical characteristics of each would be interesting general anesthetic agents. This prediction might be made more specific by further reference to the theory of the relationship between chemical constitution and pharmacological action. In certain homologous series of absorbable aliphatic compounds (as the monohydric alcohols) toxicity increases (without a comparable increase in desired activity), in proportion to the number of carbon atoms in the straight carbon chain. Also related to chemical structure in such a series are certain anesthetically important physical properties, such as boiling points. So, one might venture to anticipate that the higher members of our proposed homologous series of unsaturated ethers would not be found as satisfactory inhalation anesthetic substances as the lower members of the series, because of too high boiling points and too great toxicity. Through the kindness of Professor Sigmund Fraenkel of Vienna, we obtained vinyl-ethyl ether, allyl-ethyl ether, and di-allyl ether, and through the courtesy of Professor Lauder Jones of Princeton, we secured from Doctor Randolph Major di-vinyl ether, vinyl-ethyl ether, and isopropenyl-ethyl ether. These agents are all volatile colorless liquids with odors varying from the rather pleasant aromatic vapor of di-vinyl ether to the pungent irritation of the allyl compounds. Unfortunately only small quantities of these substances could be supplied (none in excess of 12 cc), so that only tentative determinations could be made of their partition coefficients and of their action on inhalation in mice.