Programs for ASTM Hydrocarbon Types Analyses
The PCMASPEC programs used to calculate results for the ASTM methods are briefly described below. All spectra must be in the LoRes .PC3 format. Appropriate test spectra and an operating manual are included with each program.
D2424. Molecular type and molecular weight distributions for propylene oligomers are calculated for ASTM D 2424. Mixtures having average carbon numbers between C9 and C15 and containing negligible amounts of C8 and lower hydrocarbons are analyzed for paraffins, mono-olefins, CnH2n-2, CnH2n-4, CnH2n-6, and CnH2n-8 types, which are reported by liquid-volume percent. A carbon-number distribution is calculated for the mono-olefins, as well as their average molecular weight. Although D 2424 is no longer supported by ASTM, the program is still available through PCMASPEC.
D2425. This program calculates the analysis of virgin middle distillates (400-650°F, 204-343°C) for four saturated hydrocarbon types and seven aromatic types. The sample must be physically separated into saturate and aromatic fractions using ASTM D 2549, and the fractions are analyzed separately by mass spectrometry. The program calculates weight percents for compound types from both separations and combines the results.
D2786. The analysis of a saturate fraction obtained by D 2549 and having an average carbon number between C16 and C32 is calculated. The analysis provides liquid-volume percents and weight percents for paraffins, naphthenes in the range of one through six rings, and alkylbenzenes. A carbon number distribution is included. The aromatics content must be low, and it is calculated primarily for checking the results from the saturates isolation. See also D3239 below.
D2786X. This program provides an extension of D 2786. By extrapolation of the matrix elements the average carbon number has been extended to C36. The resulting method is otherwise identical to D 2786, but it is not approved by ASTM.
D2789. The analysis of a low-olefin, gasoline-range distillate boiling below 411°F (210°C) is calculated. The output includes liquid-volume percents and weight percents for paraffins, one- and two-ring cycloparaffins, alkylbenzenes, benzonaphthenes, and naphthalenes. In addition, the program calculates a carbon-number distribution for the alkylbenzenes.
D3239. ASTM D 3239 is a companion method to D 2786. The program calculates the analysis of non-olefinic aromatic fractions boiling in the range from 401°F to 1004°F (205°C to 540°C). Liquid-volume percents and weight percents are given for 18 aromatic hydrocarbon types and 3 aromatic sulfur types. The fraction is obtained by silica-gel separation of the whole distillate using D 2549.