Solvation and Hydrogenation of Coal

Orchin, Milton; Storch, H. H.

doi:10.1021/ie50464a010

Cited by 63 publications

(19 citation statements)

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“…Model compound studies carried out by several investigators (Brower 1977;Collins et al 1977;Orchin and Storch 1948) are summarized in Table i which indicates the relative stability of various bonds. It appears that ether linkages, both aliphatic and mixed aromatic-aliphatic, are relatively easily broken, and both aliphatic and aromatic hydrocarbons are obtained.…”

Section: Introductionmentioning

confidence: 99%

Thermal Degradation of Kraft Lignin in Tetralin

Connors¹,

Johanson²,

Sarkanen³

et al. 1980

Holzforschung

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WA 98195 and from the U.S. Forest Products Laboratory, Madison, WI 53705 Keywords Kraft lignin Lignin model compounds Hydrocracking Phenols Tetralin Schlüsselwörter (Sachgebiete) Kraftlignin Lignin-Modellverbindungen Hydro-Verkrackung Phenole Tetralin Thermal Degradation of Kraft Lignin in Tetralin SummaryHydrocracking of kraft lignin (Indulin-AT) and of model compounds p-ethylguaiacol and dehydrodihydrodiisoeugenol (DDDI) was studied with tetralin äs hydrogen donor in the temperature ränge 375 to 400° C. It was found that aliphatic oxygen functions reacted most rapidly. The aromatic methoxyl groups underwent either methyl-oxygen or ring-oxygen cleavage forming catechol and phenol groups, respectively. The former process is more prevalent at higher temperatures. Side-chain cleavages resulted in the general lowering of molecular weight and formation of monomeric phenols. Careful analysis of the latter products suggested that these cleavages occurred mostly between the a-and ß-carbon atoms but cleavages between the aromatic ring and the -carbon also occurred. Upon prolonged hydrocracking, guaiacols and catechols disappeared while a mixture of phenol, cresols and ethyl phenols was relatively resistant towards further conversions. Thermischer Abbau von Kraftlignin in TetralinZusammenfassung Die Hydro-Verkrackung von Kraftlignin (Indulin AT) und von Modellverbindungen wie p-Äthyl-guajakol und Dehydrodihydro-Diisoeugenol (DDDI) wurde mit Tetralin als Wasserstoff-Donator im Temperaturbereich von 375 bis 400° C untersucht. Dabei wurde festgestellt, daß die Sauerstofftragenden Seitenketten sehr schnell reagieren. Die aromatischen Methoxylgruppen unterliegen entweder Methyl-Sauerstoff-oder Ring-Sauerstoff-Spaltung, wobei Catechol-bzw. PhenolGruppen gebildet werden. Der erstgenannte Prozeß läuft vorzugsweise bei höheren Temperaturen ab. Infolge der Seitenketten-Spaltung erniedrigt sich allgemein das Molekulargewicht, und es entstehen monomere Phenole. Genaue Analysen der letztgenannten Produkte weisen darauf hin, daß diese Spaltungen meistens zwischen dem a-und /3-Kohlenstoffatom vorkommen, aber auch zwischen dem aromatischen Ring und dem «-Kohlenstoff. Bei längerer Verkrackung verschwinden die Guajakol-und Catechol-Verbindungen, während eine Mischung von Phenol, Kresol und Äthylpheriolen relativ resistent gegen weitere Umwandlungen war.

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Section: Introductionmentioning

confidence: 99%

Thermal Degradation of Kraft Lignin in Tetralin

Connors¹,

Johanson²,

Sarkanen³

et al. 1980

Holzforschung

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“…15 Their results show that a hydroaromatic with a phenolic group, such as o-cyc1ohexy1pheno1, is even more effective in dissolving coal than tetra1in at 400 o C.…”

Section: A Coal Liquefactionmentioning

confidence: 99%

Interaction of organic solvents with a subbituminous coal below pyrolysis temperature

Dorighi¹

1977

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“…The extensive literature on this subject, including generally accepted pathways for hydrogen transfer fiom a donor solvent, was summarized by Chawla et al (1989). Tetralin is widely accepted as a hydrogen-donor solvent, though its involvement in the liquefaction process of coal is quite complex (Orchin et al, 1948;Curran et al, 1967). The major product of tetralin conversion is naphthalene.…”

Section: Bmentioning

confidence: 99%

Effect of tetralin on polymer degradation in solution. [Quarterly report, January--March 1995]

Madras¹,

Smith²,

McCoy³

1995

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DISCLAIMERPortions of this document may be illegible in electronic image products. Images are produced from the best available original document. AbstractThe effect of a hydrogen-donor solvent (tetralin) on the thermal degradation of poly(styrene-allyl alcohol) in solution was investigated in a steady-state tubular flow reactor at 1000 psig (6.8 MPa), at various tetralin concentrations (0-50 %), polymer concentrations ( 1-4 g/L), and temperatures (1 30-200 C). The molecular weight distributions of the emuent at each condition were examined as a fbnction of residence time by gel permeation chromatography. In the presence of tetralin, the polymer degrades by depolymerization to specific low molecular weight compounds and by random chain scission. No reaction was observed in the solvent 1-butanol in the absence of tetralin. The experimental data were interpreted with a rate expression first-order in polymer concentration based on continuous mixture kinetics, and rate coefficients were determined for the specific and random degradation processes. Activation energies were in the range of 5-10 kcaVmol for specific degradation and 33 kcdmol for the random degradation process. A plot of rate coefficients versus tetralin concentration indicates a fist-order rate at low tetralin concentrations and a zero-order dependence at high tetralin concentrations. In fro ductionThe thermal degradation of polymers is of considerable importance fiom both practical and theoretical points of views (Allen and Edge, 1992) : the degradation of polymers in high-temperature environments can limit their applications (Hawkins, 1984); induced degradation can potentially be used in recycling waste plastics (Powell, 1990; Miller, 1994); thermal degradation by pyrolysis coupled with gas chromatography is an important analytical procedure for identitj?ng polymeric structure (Flynn and Florin, 1985).Thermolytic degradation of polymers is similar in some respects to other important thermal decomposition processes, e.g., petroleum cracking and coal thermolysis. All these processes involve complex mixtures, both as reactants and as products. Simha and Wall (1958) and Jellinek (1955) did some early work on the degradation of polymers by measuring the yield of monomer, rate of decrease of molecular weight, and rate of volatilization. They developed rate expressions using tiee-radical mechanisms. This research was later followed by Madorsky (1964) McGrady, 1985, 1986). The treatment of the general set of equations for initiation, propagation, transfer, and termination reactions can be classified by two approaches: a. b.A statistical theory of random breaking of links (Simha and Wall, 1958; Wall, 1962;Jellinek, 1978) was proposed, and all reactions that form the intermediates and the species were assumed to start From a monodisperse sample (single MW).The desired fbnctions were either obtained by probability considerations of breakage of links, or by the solution of differential rate equations. However, since these theories were derived for a...

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Solvation and Hydrogenation of Coal

Cited by 63 publications

References 2 publications

Thermal Degradation of Kraft Lignin in Tetralin

Thermal Degradation of Kraft Lignin in Tetralin

Interaction of organic solvents with a subbituminous coal below pyrolysis temperature

Effect of tetralin on polymer degradation in solution. [Quarterly report, January--March 1995]

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