Properties of High Molecular Weight Hydrocarbons

Abstract

INTERPRETATIONof the effect of molecular constitution on the physical properties of pure substances has contributed greatly to man's understanding of the physical world, and has often permitted the segregation and evaluation of intraand intermolecular effects. Because of the variety of molecular structures possible, compounds of carbon have been especially useful in such investigations, and the compounds of carbon and hydrogen are usually taken as reference structures to which other carbon compounds are related. For these and other cogent reasons,

Viscosity of normal-hexadecane

“…The API Project 44 [8] selected value is based on the work of U bbelohde and Agtha (as reported by Engler and HOfer) [5], of Evans [6], and of N ederbragt and Boelhouwer [7], together with information from API R esear ch Proj ects 42 and 44. This selected value appears to be high, but within its estimated uncertainty, i. e., 0.003 to 0.030 cp , it agrees with the value r eported here and the value reported by Schies ler and co-workers [9].…”

“…Thus uncertainties in the density of t h e sample, though small , do contribute to the uncertain t y of the value found for absolute viscosity. In the present work, wit h the t wo small dilatom eters, t he densities of t h e NBS standard sample and of the composite sample were found t o be 0.77344 g/cm 3 , which agrees with the API Proj ect 44 [8] selected value of 0.77342 g/cm3 • With t. he large dilatometer, the density of the composite sample was found to b e 0.77370 g/cm3 which agrees with the value 0.7737 g/cm3 r eported by Sehiessler and co-workers [9]. The values obtained wit h t he small instruments were interpreted as indicating t hat the densities of t h e two samples were esse ntially the same.…”

Extended hard-sphere model for predicting the viscosity of long-chain n-alkanes

“…The data of Queimada and co-workers for other fluids studied in this work ( n-C 20 H 42 and n-C 22 H 46 ) are reproduced with the maximum deviation of 2.5 %, while as discussed previously the data for shorter chain alkanes (n-C 7 H 16 , n-C 10 H 22 and n-C 16 H 34 ) are reproduced within the overall AAD of 2.2 % and the maximum deviation of 5.1 %, so it is not too surprising to observe under prediction of 6.6 % to 6.9 % for n-C 24 H 50 . An indication that the uncertainty of these measurements might be higher than for other [46]; () n-C20H42 [47]; () n-C20H42 [48]; () n-C20H42 [49]; () n-C22H46 [48]; () n-C24H50 [48]; () n-C24H50 [50]; () n-C28H58 [44]; () n-C32H66 [51]; ( ) n-C36H74 [44]; () n-C44H90 [51]; alkanes is provided by the good agreement of the model with the data of Wakefeld and coworkers [50], who also measured the viscosity of tetracosane but in a capillary viscometer, and whose data is reproduced within 1-2 %. The four high pressure data points ( P > 42 Table 4.…”

“…A literature search indicates that the measurements of viscosity of long-chain n-alkanes are scarce and only 15 datasets could be used in the development of the correlation. Table 3 summarizes the available data [44][45][46][47][48][49][50][51] detailing the technique employed to perform the measurements, the temperature and pressure ranges and the authors' claimed uncertainty.…”

“…Only for two alkanes were the measurements reported by more than a single laboratory. The viscosity of icosane (n-C 20 H 42 ) has been measured by three different authors [47][48][49], while the viscosity of tetracosane (n-C 24 H 50 ) has been measured by two investigators [48,50], in the overlapping temperature range at atmospheric pressure. The data on icosane agrees within ±1.5 % with each other, while for tetracosane we observe a systematic difference of approximately 5 %, with the viscosity data of Queimada et al [48] being lower than that measured by Wakefield et al [50].…”