Purification, purity, and freezing points of 7 heptanes, 16 octanes, 6 pentenes, cyclopentene, and 7 C9H12 alkylbenzenes of the API-standard and API-NBS series

Measurements of the refractive index at 20°, 25°, and 30° C and at se ven wavelengths, from 6678.1 to 4358.3 Angstrom units , were made on 60 purified hydrocarbons of t he API-NBS series. The apparatus consisted of a precision Abbe-type refractomcter, calibrated by m eans of NBS Standard Samples of hydrocarbons certified with respect to refractive index at thc th ree tcmperatures and seven wavelengths uscd. The light SOU l'ces used were a mercury arc, a sodium vapor lamp, and h ydrogen and helium discharge tubes, w ith suitable filL er . A constant t empe rature bath maintained the te mpe rature of the refractomete r prism s constant within ± 0.02° C.The experimental daLa on the hydrocarbons were adjusted by m ean s of a four constan t Hartmann equation , nA=n ",+C/(A-A*) 1.6, and a two constant modified Cauch y equation , fln, =a+ b/ X2• (fln)., t he change in t he refracti ve index a t t he wavele ngth, A, when the t e mpem t ure is chan ged from 20° to 25° C or 25° t o 30° C, is used instead of n, of the Cauchy eqllation).The compu ted refractive index a L 20°, 25°, an I 30° C, t oge Lher with the values of t h e specific di spers ions, and the constants of the HarLmann and m odified Cauchy equat ions, applicable over the ran ge of m ea l11'e ment, a re rep or ted for 60 API-NBS h yd rocarbo ns, comprising 17 paraffins, 14 alkylcyclop entanes, 8 alkylcyclohexanes, and 21 alky lbenze nes.

Section: Apparatus and Proceduresmentioning

confidence: 99%

Section: Source and Purity Of Compoundsmentioning

confidence: 99%

Refractive index as a function of wavelength for sixty API-NBS hydrocarbons

Forziati¹

1950

“…The procedure followed in the process of purification and determination of purity was the same as that described in the previous r eports [2,3,4], except that in the purification of 2,2,3-trimethylbutane, 2,2,4-trimethylpentane, 1,2-diethylbenzene, and 1,4-diethylbenzene, use was made of the process of adsorption.…”

Section: Purificationmentioning

confidence: 99%

Purification, purity, and freezing points of 30 hydrocarbons of the API-Standard and API-NBS series

Streiff¹,

Zimmerman²,

Soule³

et al. 1948

“…This volume may be compared for each compound with the volume of the starting material given in the third column. The heart cut was selected largely on the basis of refractive index and boiling point, although, as will be shown in the next report on the purification of API-NBS hydrocarbons [3], this is a procedure which frequently results in the discarding of the best material. Each final lot was filtered through silica gel [4] to remove water and nonhydrocarbon impurities.…”

Section: Materials and Purificationmentioning

confidence: 99%

“…The purity of the actual sample was calculated according to the method described in section VIII of reference [5], using the values of the freezing point of the actual sample and the freezing point for zero impurity determined in this investigation, (except as -otherwise indicated), together with values of the cryoscopic constants obtained from the" z" tables of the American Petroleum Institute Research Project 44 [6] or from unpublished data from references [3] and [8]. For each of the compounds except 3-methylpentane, table 2 indicates whether freezing or melting experiments were used, and gives the values of the freezing point of the actual sample, the freezing point for zero impurity where determined in this investigation, and the calculated amount of impurity.…”

Section: Freezing Points and Puritymentioning

confidence: 99%

Purification, purity, and freezing points of 31 hydrocarbons of the API-NBS series

Ar¹,

Et²

1946

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