Catalysis of gas and liquid phase ionic and radical rearrangements of α- and β-pinene by metal(IV) phosphate polymers

Costa, Magda; Johnstone, R. A. W.; Whittaker, D.

doi:10.1016/1381-1169(95)00124-7

Cited by 31 publications

(11 citation statements)

References 8 publications

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“…There results agree with those of Costa et al [30] for thermal isomerization of a-pinene. Table 10 shows the principle components arising from the pyrolysis of b-pinene.…”

Section: Experimental Analysis Of the Decomposition Products During Psupporting

confidence: 94%

Synthesis of myrcene by pyrolysis of β-pinene: Analysis of decomposition reactions

Kolicheski

Côcco

Mitchell

et al. 2007

Journal of Analytical and Applied Pyrolysis

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“…There results agree with those of Costa et al [30] for thermal isomerization of a-pinene. Table 10 shows the principle components arising from the pyrolysis of b-pinene.…”

Section: Experimental Analysis Of the Decomposition Products During Psupporting

confidence: 94%

Synthesis of myrcene by pyrolysis of β-pinene: Analysis of decomposition reactions

Kolicheski

Côcco

Mitchell

et al. 2007

Journal of Analytical and Applied Pyrolysis

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“…The mechanism involves biradicals and comprises a decyclization reaction (8). A transformation of cyclic monoterpenes into acyclic monoterpenes via ionic intermediates has, to our knowledge, never been reported (5,8). The opposite is well known: all natural cyclic monoterpenes are synthesized via cationic intermediates (4,14).…”

Section: Discussionmentioning

confidence: 99%

Geranic Acid Formation, an Initial Reaction of Anaerobic Monoterpene Metabolism in Denitrifying Alcaligenes defragrans

Heyen

Harder

2000

Appl Environ Microbiol

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Monoterpenes with an unsaturated hydrocarbon structure are mineralized anaerobically by the denitrifying ␤-proteobacterium Alcaligenes defragrans. Organic acids occurring in cells of A. defragrans and culture medium were characterized to identify potential products of the monoterpene activation reaction. Geranic acid (E,E-3,7-dimethyl-2,6-octadienoic acid) accumulated to 0.5 mM in cells grown on ␣-phellandrene under nitrate limitation. Cell suspensions of A. defragrans 65Phen synthesized geranic acid in the presence of ␤-myrcene, ␣-phellandrene, limonene, or ␣-pinene. Myrcene yielded the highest transformation rates. The alicyclic acid was consumed by cell suspensions during carbon limitation. Heat-labile substances present in cytosolic extracts catalyzed the formation of geranic acid from myrcene. These results indicated that a novel monoterpene degradation pathway must be present in A. defragrans.The mineralization of organic matter by microorganisms is often severely hampered by the chemical structure of the substrate. In the presence of oxygen, mono-and dioxygenases catalyze the oxidative functionalization of recalcitrant compounds, i.e., hydrocarbons. Microbial mineralization of such substances also occurs in nature in the absence of molecular oxygen, and in the last decade anaerobic bacteria have been isolated on substances such as alkylbenzenes (6, 18, 22), alkanes (1, 7, 25, 26), and alkenes (15). Thus far, the biochemistry of the initial activation reactions has been revealed only for toluene. Catalysis via radicals seems to be involved in the addition of toluene to fumarate by the enzyme benzylsuccinate synthase, a putative glycine radical enzyme (3,21). This novel enzyme raises the question of how the activation of alkanes and alkenes commences.Monoterpenes are ubiquitous alkenes in nature (Fig. 1). The physiological trait of anaerobic mineralization of monoterpenes to carbon dioxide has been demonstrated by the enrichment and isolation of denitrifying strains of Alcaligenes defragrans and Thauera terpenica (11,12,16). During growth of bicyclic monoterpenes, e.g., ␣-pinene, traces of monocyclic monoterpenes are detected, suggesting menthadienes as intermediates (19). A. defragrans cometabolically catalyzes the transformation of isolimonene to isoterpinolene. This 3,1-hydrogen-⌬ 1 -⌬ 3 -mutase reaction confirms the microbial activation of alkene bonds that are not polarized by adjacent functional groups. It also indicates the necessity for a sp 2 hybridization of the C-1 atom in order for microbial monoterpene oxidation to occur (19).It seems likely that the unsaturated monoterpenes may be transformed initially into an organic acid, because intermediates in catabolic pathways are usually organic acids, e.g., in the citrate cycle. If this acid cannot diffuse through membranes, the carbon source is fixed in the cell. To explore this hypothesis, we characterized the organic acids in cells and culture medium and studied the formation of geranic acid (3,7-dimethyl-2,6-trans,trans-octadienoic acid) in cells ...

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“…Titanium phosphate is a versatile catalyst used in various transformations as the isomerisation of -pinene at 165 °C [30], the formation of cyclic ethers from unsaturated alcohols [27], the selective ketalization of ketones [28], the oxidation of phenol to hydroquinone and catechol [36] and the hydroxylation of phenol and 2-naphthol [37].…”

Section: Titanium Phosphatementioning

confidence: 99%

Phosphates: New Generation of Liquid-Phase Heterogeneous Catalysts in Organic Chemistry

Sebti¹,

Zahouily²,

Lazrek³

et al. 2008

COC

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This two part review looks at the uses of phosphate based heterogeneous catalysts for a range of synthetic organic reactions. Many different phosphates are known and have been tested as catalysts in a wide range of reaction types, either as catalysts, or in combination with other species such as zinc chloride or KF. The first section deals with the wide variety of phosphates which have been utilized in organic chemistry, while the second focuses more tightly on catalysts derived from naturally occurring phosphates. In all cases, efficient reactions can be achieved and in many reactions, significant solvent effects have been noted. Of benefit is the fact that relatively benign solvents such as lower alcohols and water are often the most effective.

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Catalysis of gas and liquid phase ionic and radical rearrangements of α- and β-pinene by metal(IV) phosphate polymers

Cited by 31 publications

References 8 publications

Synthesis of myrcene by pyrolysis of β-pinene: Analysis of decomposition reactions

Synthesis of myrcene by pyrolysis of β-pinene: Analysis of decomposition reactions

Geranic Acid Formation, an Initial Reaction of Anaerobic Monoterpene Metabolism in Denitrifying Alcaligenes defragrans

Phosphates: New Generation of Liquid-Phase Heterogeneous Catalysts in Organic Chemistry

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