Thermal Isomerization of Levopimaric Acid

Loeblich, Virginia M.; Baldwin, Doris E.; O’Connor, Robert T.; Lawrence, Ray V.

doi:10.1021/ja01628a071

Cited by 30 publications

(17 citation statements)

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“…During supercritical gas extraction levopimaric, palustric and neoabietic acids totally disappeared while the amount of dehydroabietic acid increased. These results are in good agreement with earlier observations (Takeda et al 1968;Joye and Lawrence 1961;Loeblich et al 1955;Loeblich and Lawrence 1957;Hafizoglu 1979). When levopimaric acid is subjected to heat, isomerization occurs with the formation of abietic, neoabietic and palustric acids (Loeblich et al 1955).…”

Section: Resultssupporting

confidence: 93%

“…These results are in good agreement with earlier observations (Takeda et al 1968;Joye and Lawrence 1961;Loeblich et al 1955;Loeblich and Lawrence 1957;Hafizoglu 1979). When levopimaric acid is subjected to heat, isomerization occurs with the formation of abietic, neoabietic and palustric acids (Loeblich et al 1955). Palustric and abietic acids appear to be formed in approximately equal amounts at first with a smaller portion of neoabietic acid.…”

Section: Resultssupporting

confidence: 93%

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Fatty and Resin Acids Recovered from Spruce Wood by Supercritical Acetone Extraction

Demırbas¹

1991

Holzforschung

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Soxhlet and Supercritical gas extracts of freshly cut Oriental spruce (Picea orientalis) were recovered using acetone at 240°C and 6.0-6.5 MPa.The yield of Soxhlet extract was 1.6% and the yield of Supercritical gas extract was 6.8% by weight on a dry spruce powder basis. The fatty and resin acids present in the extracts were separated by chemical methods and analysed by combined gas chromatography-mass spectrometry. The yield of fatty acids from the Supercritical gas extract was about four times äs high äs the yield of Soxhlet extract but the increase in the yield of resin acids was slight.

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Section: Resultssupporting

confidence: 93%

Section: Resultssupporting

confidence: 93%

Fatty and Resin Acids Recovered from Spruce Wood by Supercritical Acetone Extraction

Demırbas¹

1991

Holzforschung

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“…The present findings seem to contradict the results obtained in the past, in which abietic acid was the end product of thermal, acid and base catalyzed isomerization of palustric-, neoabietic-and levopimaric acids (Loeblich et al 1955;Baldwin et al 1956;Loeblich and Lawrence 1957;Schuller et al 1960;Schuller and Lawrence 1965).…”

Section: Organosolv Pulping Ofmodel Compoundscontrasting

confidence: 99%

Behavior of the Major Resin- and Fatty Acids of Slash Pine(Pinus elliottiiEngelm.) During Organosolv Pulping

Quinde¹,

Paszner²

1992

Holzforschung

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Behaviour of slash pine wood (Pinus elliottii Engelm.) extractives during pulping using catalyzed 80% aqueous methanol, was studied in detail. Particularly, the main resin-and fatty acids (RAFA) were characterized before and after the pulping trials. RAFAthus collected were saponified and/or methylated and characterized by gas liquid chromatography (GC or GLC) and gas chromatography-mass spectrometry. Pulping experiments were performed at 205°C for periods of 5, 20, 40 and 60 min. RAFAsurviving the high-temperature pulping process, were found mainly in the black liquor.The extractives were recovered from the black liquor by a selective tertiary component liquid/liquid extraction procedure, using diethyl ether äs the third (extracting) solvent. In the black liquor, substantial quantities of resin acids (89.8%) and fatty acids (25.6%) were detected already after 5 min cooking. After a 60 min cook the black liquor contained 78.1% and 71.6% resin-and fatty acids, respectively, while the pulp retained 11.7% and 8.2%, respectively. Effective extractives removal from the black liquor was observed on precipitation of the lignin (Lignin II) by dilution with 10 times volume of water. Lignin II can potentially carry 98% and 60.4% of the resinand fatty acids, respectively, leaving only minor amounts of resin acids (2%) and some fatty acids (39.6) dissolved in the aqueous filtrate. A small fraction of lignin which precipitates on cooling of the black liquor ("Lignin I") adsorbed and carried 10.2% and 20.2% of the resin-and fatty acids, respectively. Methods for recovery of an uncontaminated (by extractives) lignin are discussed. Opportunities for generating another byproducts stream, by organosolv pulping of resinous woods, are pointed out.These same considerations motivated organosolv pulping trials by Klcinert andTaycnthal in 1931 using aqueous cthanol äs the pulping solvent for woods at tempcratures similar to those uscd in kraft pulping. In later experiments with 50:50 ethanol-watcr at 185 °C, it Holzforschung /Vol. 46 /1992 / No. 6

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“…We observed that the decomposition temperature decreased with increasing content of rosin during the addition process. This confirmed that the decomposition reaction of the adducts was very complex, with the participation of at least three compositions, including the addition product, unreacted tung oil, and rosin, and two different mechanisms during thermal decomposition. The first thermal degradation stage, situated between 220 and 280°C, with a mass loss of about 5 wt %, was attributed to the decomposition of COOH groups bonded to hydrophenanthrene moieties.…”

Section: Resultssupporting

confidence: 59%

“…Figure shows the UV absorption spectra of the primary material and the product. The maximum absorption peak of rosin appeared at 241 nm, whereas the maximum absorption peak appeared at 270 nm with a large redshift after 4 h at 170°C; this indicated that the hydroabietic acid structure of rosin was converted to LEA . Strong absorption bands at 261, 271, and 282 nm were observed in the UV–vis absorption spectra; these corresponded to its higher unsaturation and conjugated triene.…”

Section: Resultsmentioning

confidence: 95%

Synthesis of a tung oil–rosin adduct via the diels–alder reaction: Its reaction mechanism and properties in an ultraviolet‐curable adhesive

Zhang

Ma³

et al. 2013

J of Applied Polymer Sci

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A Diels-Alder adduct of rosin with tung oil was effectively prepared for use as a filler and adhesion promoter in UVcurable adhesives. The characteristics of the adduct were analyzed by Fourier transform infrared (FTIR) spectroscopy and ultravioletvisible (UV-vis) absorption spectra. The reaction mechanism was studied with gel permeation chromatography, thermogravimetric analysis, 1 H-NMR, and the density functional theoretical method. The FTIR and 1 H-NMR results showed that the Diels-Alder addition occurred between the rosin and tung oil. The still-existing characteristic peaks of the conjugated diene in the adduct, as shown in the FTIR and UV-vis absorption spectra, indicated that the most favorable reaction between the rosin and tung oil was when the rosin was used as the conjugated diene and the tung oil was used as the dienophile. The molecular weights of the adduct with different molar ratios showed that the most possible addition molar ratio between the rosin and tung oil was 3:1. The favorable addition mechanism was further proved by a comparison of the relative energies of different isomers of the adduct with theoretical calculation, and the most stable structure of adduct showed that the addition position of tung oil was the terminal C@C double bond. The properties analysis indicated that the adduct could improve the adhesion of UV-curable adhesives and reduce the curing shrinkage rate.

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Thermal Isomerization of Levopimaric Acid

Cited by 30 publications

References 0 publications

Fatty and Resin Acids Recovered from Spruce Wood by Supercritical Acetone Extraction

Fatty and Resin Acids Recovered from Spruce Wood by Supercritical Acetone Extraction

Behavior of the Major Resin- and Fatty Acids of Slash Pine(Pinus elliottiiEngelm.) During Organosolv Pulping

Synthesis of a tung oil–rosin adduct via the diels–alder reaction: Its reaction mechanism and properties in an ultraviolet‐curable adhesive

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