Alcohols as H-donor media in coal conversion. 1. Base-promoted H-donation to coal by isopropyl alcohol

Ross, David S.; Blessing, James E.

doi:10.1016/0016-2361(79)90084-x

Cited by 100 publications

(25 citation statements)

References 6 publications

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“…Similarly, it was reported that isopropyl alcohol is converted to acetone and hydrogen gas with KOH at 335 "C [12], and it has been suggested that methanol would undergo similar reactions [ 11,171. These results suggest the higher order products in our system may have formed stepwise as follows: ethylene formation from ethanol, ethylene oligomerization, olefin hydrolysis (butanol, hexanol), alcohol oxidation (butanoic acid), esterification (upon acidification).…”

Section: Model Compound Studiesmentioning

confidence: 88%

Batch Microreactor Studies of Lignin Depolymerization by Bases. 1. Alcohol Solvents

Miller¹,

Evans²,

Mudd³

et al. 2002

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Biomass feedstocks contain roughly 10-30% lignin, a substance that can not be converted to fermentable sugars. Hence, most schemes for producing biofuels (ethanol) assume that the lignin coproduct will be utilized as boiler fuel to provide heat and power to the process. However, the chemical structure of lignin suggests that it will make an excellent high value fuel additive, if it can be broken down into smaller molecular units. From fiscal year 1997 through fiscal year 2001, Sandia National Laboratories was a participant in a cooperative effort with the National Renewable Energy Laboratory and the University of Utah to develop and scale a base catalyzed depolymerization (BCD) process for lignin conversion. SNL's primary role in the effort was to utilize rapidly heated batch microreactors to perform kinetic studies, examine the reaction chemistry, and to develop alternate catalyst systems for the BCD process. This report summarizes the work performed at Sandia during FY97 and FY98 with alcohol based systems. More recent work with aqueous based systems will be summarized in a second report.Batch microreactor studies demonstrated that the conversion of lignin to ether solubles by KOH in methanol or ethanol was rapid at 290 "C, reaching the maximum value (only 7% ether insoluble material remaining) within 10-15 minutes. Model compound studies confirmed that the dominant depolymerization route is the solvolysis of ether linkages. Strong bases (KOH, NaOH, CsOH) were shown to convert more of the lignin to ether soluble material than weaker bases (LiOH, Ca(OH)2, and Na2C03). An excess of base relative to lignin monomer units is required for maximum conversion. However, a synergistic interaction between NaOH and Ca(OH)* allows reasonable conversions of lignin to be achieved with small amounts of NaOH by coupling it with Ca(OH)2. Ethanol and methanol are converted to acetic and formic acid respectively under the reaction conditions with an activation energy of approximately 50 kcal/mol. This results in a loss of solvent, but more importantly neutralizes the base catalyst, halting forward progress of the reaction, and accounting for the excess base requirement.3

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Section: Model Compound Studiesmentioning

confidence: 88%

Batch Microreactor Studies of Lignin Depolymerization by Bases. 1. Alcohol Solvents

Miller¹,

Evans²,

Mudd³

et al. 2002

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“…Hydrocarbons, gasoline, olefins and methanol are typical examples of products that can be obtained through this process (Goldstein, 1981).Some liquefactions, such as of coal, can be intensified through the Downloaded by [McGill University Library] at 22:29 07 February 2015 addition of catalysts such as alkali metals hydroxides(NaOH or KOH) (Makabe and Ouchi, 1978;Ross and Blessing, 1978) and Lewis acids (ZnCI 2 , SnCI 2 e FeCI 3 ) (Flores et al, 1978;Kusnetsov et aI., 1982;Mondragon et aI., 1982).…”

Section: Lancas and Peresmentioning

confidence: 98%

Upgrading of Sugar Cane Bagasse by Thermal Processes. 7. Catalytic Liquefaction in Monoethanolamine (Mea) and Preliminary Fractionation of the Obtained Products

Lanças

Peres

1996

Fuel Science and Technology International

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The liquefaction of sugar cane bagasse in monoethanolamine (MEA) in the presence of catalysts (zeolite A, non-zeolitic aluminosilicate and zinc chloride) as well as in the absence of catalysts is described in this paper. The influence of the catalysts on the yield of the generated products is verified through a fractionation method based on relative solubility parameters. The influence of the catalysts on the conversion yield was also verified. The catalysts that yields the greater quantity of oils is the non-zeolitic aluminosilicate. However, in the overall conversion process of sugar cane bagasse, the most efficient catalyst was found to be zeolite A. 963

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“…..... Final ReporttoDOI: PETC 1993 5 6 Blessing, 1979;Zhang ct al., 1993a), Figure 5-6 shows that the first-order model fits the experimental data reasonably weil. Zhang et 'al.…”

Section: Kinetic Comparisons Of Coal Thermolysis With and Without Hydmentioning

confidence: 99%

“…The research directed specifically to the kinetics of supercritical coal extraction (Slomka and Rutkowski, 1982;Deshpande et al, 1986) is based on the non-polar solvent, toluene. To our knowledge, there is little published information on supercritical extraction with polar or hydrogendonor solvents, although some research on alcohol extraction of coal (Ross and Blessing, 1979;Makabe and Ouchi, 1981) has been reported. Higher conversions were reported with low molecular weight alcohols than with hydrocarbons under equivalent conditions (Amestica and Wolf, 1984;Vasilakos et al, 1985), possibly due to hydrogen-donor action.…”

mentioning

confidence: 99%

Chemical kinetics and transport processes in supercritical fluid extraction of coal. Final report, August 10, 1990--December 30, 1992

McCoy¹,

Smith²,

Wang³

et al. 1993

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The overall objective of this project was to study the supercritical fluid extraction of hydrocarbons from coal. Beyond the practical concern of deriving products from coal, the research has provided insights into the structure, properties, and reactivities of coal. Information on engineering fundamenrals of coal thermolysis and extraction, including physical and chemical processes, is presented in this final report. To accomplish the goals of the project we developed continuous-flow experiments for fixed-bed samples of coal that allow two types of analysis of the extract: continuous spectrophotometric absorbance measurements of the lumped concentration of extract, and chromatographic determinations of molecultu'-weight distributions as a function of time. A kinetic model has been derived tbr the prim_u'y reactions of coal thermolysis both in the presence and absence of excess hydrogen-donor solvent. The model, an extension of previous published mechanisms, is based on a proposed free-radical mechanism following classical freeradical chemistry. First, free-radical reactions are assumed to occur both on the solid surface and in the liquid film around the coal particle. Second, the elementary reactions (initiation, propagation, and termination) are formulated to describe the overall process. The model, based on assumptions of adsorption-desorption equilibrium and stationary-state concentxation of free radicals, includes second-order and first-order terms. The second-order term is a measure of the effect of hydrogen transfer on coal conversion, lt is important in the initial stage of liquefaction and becomes negligible when donor solvent concentration vanishes. The supercritical ten-butanol extraction of Illinois No. 6 bituminous coal involves both physical and chemical processes. Extraction rates were estimated by continuously measuring the spectrophotometric absorbance (at 235 nra) of the effluent from a fixed-bed flow reactor. The experiments were conducted in the temperature range of 553-633 K and at 6.8 MPa constant pressure by programmed-temperature techniques. A model for which the extractable compounds in the coal are represented by two groups of components, undergoing parallel first-order reactions, satisfactorily describes the experimental data. The kinetics data indicate that the Iu'st group is extracted by a physical process, which occurs below 573 K. The second group is extracted via a thermal decomposition, or thermolytic, reaction twith an apparent average activation energy of 54 kJ/gmol), which is dominant above 573 K. A kinetic model representing the primary reactions of coal thermolysis is tested with the experimental data of extraction of coal in a flow reactor. The experiments were performed at supercritical conditions (593,613,633,653 K and 6._ MPa) with a mixed solvent of tetralin and ten-butanol. The coal sample (Illinois No. 6) was pretreated to eliminate the physically-extractable compounds. The kinetic model including first-and second-order terms successfully descnbed the 4 KINETICS OF COAL...

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Alcohols as H-donor media in coal conversion. 1. Base-promoted H-donation to coal by isopropyl alcohol

Cited by 100 publications

References 6 publications

Batch Microreactor Studies of Lignin Depolymerization by Bases. 1. Alcohol Solvents

Batch Microreactor Studies of Lignin Depolymerization by Bases. 1. Alcohol Solvents

Upgrading of Sugar Cane Bagasse by Thermal Processes. 7. Catalytic Liquefaction in Monoethanolamine (Mea) and Preliminary Fractionation of the Obtained Products

Chemical kinetics and transport processes in supercritical fluid extraction of coal. Final report, August 10, 1990--December 30, 1992

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