Carbonyl Groups in Lignin. II. Catalytic Hydrogenation of Model Compounds Containing Aryl Carbinol, Aryl Carbinol Ether, Ethylene, and Carbonyl Groups.

Adler, Erich; Marton, Josef; Steinsvik, Sigurd; Palmstierna, H.; Sjöberg, Berndt; Toft, Jens

doi:10.3891/acta.chem.scand.15-0357

Cited by 24 publications

(5 citation statements)

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“…In the case of the benzyl-protected compounds 7, it is possible to effect full reduction to the final products 1 when acidic conditions are used for the Pd-catalysed hydrogenolysis/reduction (Adler and Marton 1961). However, we found the two-step process via the quinone methide 6 to be significantly cleaner.…”

Section: Resultsmentioning

confidence: 89%

“…S = syringyl, G = guaiacyl. The nominal molecular weights (for compounds 1) are in parentheses, ί ArOH, K 2 CO 3 , acetone, reflux (Helm and Ralph 1992;Kratzl et al 1959;Landucci et al 1981;Ralph et al 1986); it H 2 C=O, dioxane, K 2 CO 3 (Helm and Ralph 1992); in for P = CH 2 Ph, Pd/C-H 2 , EtOH (Kratzl et al 1959;Landucci et al 1981;Ralph et al 1986), for P = Ac, NaBH 4 /EtOH/H 2 O (Ralph and Helm 1991); ιΥ Me 3 SiBr, CH 2 C1 2 , followed by NaHCO 3 (Ralph and Young 1983); v NaBHU on SiO 2) CH 2 C1 2 (Ralph 1982); w Pd/C-H 2 , EtOH+H 2 SO 4 (Adler and Marton 1961;Landucci 1980). syringyl B-ring product Ib, use of commercially available 4-allyl-2,6-dimethoxyphenol is the simplest approach. However, an acetate protecting group is preferable for syringyl Α-ring compounds Ic and Id.…”

Section: Resultsmentioning

confidence: 99%

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Dimeric ß-Ether Thioacidolysis Products Resulting from Incomplete Ether Cleavage

Ralph¹,

Grabber²

1996

HFSG

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Keywords Lignin Lignin model compound ß-Elhcr ß-Aryl ether Thioacidolysis GC GC-MS NMR Milled wood lignin Willow SummaryFour ß-ether dimers which result from incomplete ß-elher cleavage of syringyl-guaiacyJ lignins following non-optimized thioacidolysis/desulfurization of plant materials were identified. The compounds were; the guaiacyl-guaiacyl dimer 3-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxy-4-propylphenoxy)propan-l -oJ, the guaiacyl-syringyl dimer 2-(2,6-dimethoxy-4-propylphenoxy)-3-(4-hydroxy-3-methoxyphenyl)-propan-1-ol, the syringyl-guaiacyl dimer 3-(3,5-dimethoxy-4-hydroxyphenyl)-2-(2-methoxy-4-propylphenoxy)-propan-l-ol, and the syringyl-syringyl dimer 3-(3,5-dimethoxy-4-hydroxyphenyl)-2-(2,6-dimethoxy-4-propylphenoxy)-propan-1-ol. Synthesis of each dimer, by extending dimeric lignin model ß-ether strategies, provided authentication of the structures.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Dimeric ß-Ether Thioacidolysis Products Resulting from Incomplete Ether Cleavage

Ralph¹,

Grabber²

1996

HFSG

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“…18 ' 19 Several lignin models were synthesized according to methods described in the literature. 20 ' 21 Their structures are depicted in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

Thermomechanical Pulp and Light -Photoactivity of α-Carbonyl Group in Solid Lignin

Hon¹

1992

Journal of Wood Chemistry and Technology

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Interactionof sunlight and UV light with thermomechanical (TMP) pulps, milled wood lignin (MWL) and various lignin model compounds in solid state was studied. It was found that TMP fibers were sensitive to these lights. During exposure, TMP lost its brightness as a function of irradiation time and increased its yellowness. The a-carbonyl group functioned as a light absorption center to promote photocleavage of C a -C fi and 6-0-4 linkages. Electron spin resonance (ESR) studies demonstrated that free radicals were generated in the interim.Phenoxy radicals appeared to be important radical intermediates that ultimately transformed into oquinonoid structures. INTRODUCTIONRapid development and utilization of thermomechanical (TMP) and chemithermomechanical (CTMP) pulps have attracted considerable attention in the pulp and paper industry in the last twenty years. Much research has been conducted to improve the quality, such as strength and color, of these products. Nonetheless, overcoming discoloration and brightness reversion of TMP and CTMP appear to be a perplexing task. The causes of

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“…The coniferyl aldehyde detected by the phloroglucinol test appears to arise by oxidation of coniferyl alcohol end units in the lignin since coniferyl aldehyde itself is not directly incorporated into lignin (Nakamura et al 1974). Up to 4 % coniferyl aldehyde units have been determined in Bjorkman lignin from spruce (Adler and Marton 1961;Marton et a! 1961), and some degradation compounds having coniferyl aldehyde units have been isolated by Sakakibara and Nakayama (1962), Nimz (1967) and Aoyama and Sakakibara (1976) from wood lignin.…”

Section: Lignin Colour Tests On Wheat Internode and Other Plant Mealsmentioning

confidence: 99%

Lignin in wheat internodes. Part 2: Alkaline nitrobenzene oxidation by wheat straw lignin and its fractions

1990

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Carbonyl Groups in Lignin. II. Catalytic Hydrogenation of Model Compounds Containing Aryl Carbinol, Aryl Carbinol Ether, Ethylene, and Carbonyl Groups.

Cited by 24 publications

References 0 publications

Dimeric ß-Ether Thioacidolysis Products Resulting from Incomplete Ether Cleavage

Dimeric ß-Ether Thioacidolysis Products Resulting from Incomplete Ether Cleavage

Thermomechanical Pulp and Light -Photoactivity of α-Carbonyl Group in Solid Lignin

Lignin in wheat internodes. Part 2: Alkaline nitrobenzene oxidation by wheat straw lignin and its fractions

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