Powhatan 5 coal

Figure 15. CP/MAS spectra of Powhatan 5 coal at three magnetic field...

Figure 16. Stack plot of C CP/MAS interrupted decoupling spectra of Powhatan 5 coal. The tallest peak in each spectrum was scaled to a umform height.

Increase in conversion is also obtained with tetralin/water mixtures (see Table VIII) in an analogous manner to the increased conversion with the addition of small amounts of tetralin to toluene (see Figure 1). Similar findings have been reported for the extraction of Powhatan coal with tetralin/water and tetrahydroquinoline/water mixtures since this work was completed (15). 

To perform a dialytic extraction, the apparatus is assembled and preextracted for 48 hours using pyridine and methylene chloride outside and inside the membrane, respectively. The coal ftvlOO g) is then slurried in a 2-3 fold excess of pyridine (ACS reagent grade) and placed in the sample compartment, where it is constantly stirred. The methylene chloride reflux is begun at this point, and the extract collects in the receiver. When the buildup of pyridine in the receiver results in stoppage of the reflux cycle, the contents of the receiver are collected, and it is refilled with clean methylene chloride. The overflow from the sample compartment was evaporated under a flow of dry nitrogen, redissolved in pyridine, and replaced in the sample compartment daily. The dialytic extraction is slower than the soxhlet procedure, and the yield is substantially less. For example, the yield of a four day dialytic extraction of Powhatan Coal was 6%, while a two day pyridine soxhlet on the same coal yields 12-15% extract. 

Acyclic Hydrocarbons. Capillary GC comparison of retention times with authentic standards and GC/MS were used to characterize the acyclic alkanes present in the CHX extracts. The extracts of Beulah 3 North Dakota lignite (B3), Wyodak Wyoming subbituminous coal (WYOl), Highvale Alberta subbituminous coal (ALBl), and Powhatan Ohio bituminous coal (POWl) all contained homologous series of n-alkanes. Table III. The low-rank coal CHX extracts for the limited members of the... 

Figure 4. Comparison of n-alkane extract distribution for Powhatan bituminous coal, A, and n-alkane distribution from CPU bottoms recycle product (Powhatan bituminous feed coal) A.

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