Selective double bond isomerization of allyl phenyl ethers catalyzed by ruthenium metal complexes

Sharma, Sumeet K.; Srivastava, Vivek; Jasra, Raksh V.

doi:10.1016/j.molcata.2005.10.005

Cited by 50 publications

(18 citation statements)

References 12 publications

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“…Typically, isomerization of eugenol is catalyzed by a homogeneous base [45] or solid base [46][47][48] or with metal complexes. [49] However, in this work, we observed, albeit in lower concentrations, the formation of isoeugenol, 21, over Pd on acidic supports (SA and AL).…”

Section: Resultscontrasting

confidence: 53%

Function of Metals and Supports on the Hydrodeoxygenation of Phenolic Compounds

Deepa

Dhepe

2014

ChemPlusChem

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Hydrodeoxygenation (HDO) is an important process for removing oxygen from lignin‐derived phenolic monomers to obtain chemicals that can be used as fuel or fuel additives. A systematic study is performed to check the effects of supports (acidic, neutral, basic) and noble metals (Pd, Pt, Ru) on the HDO of phenol, guaiacol, and eugenol. Evaluation of the combinations of metals and supports under the similar reaction conditions shows that the metals supported on a highly acidic support (SiO2‐Al2O3) yield complete hydrogenation products with the possibility of CO bond cleavage to achieve a real HDO activity, whereas on a mildly acidic support (γ‐Al2O3), a complicated product distribution is achieved, and neutral (C) and basic (HT) supports give restricted hydrogenation activity but yield the products with very high selectivity. On the basis of the results, reaction pathways are suggested and deliberated. The catalysts show reproducible activity in recycle runs. The catalysts are characterized by various techniques (XRD, TEM, TPD, ICP‐OES) to establish the catalyst activity–property relationship.

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Section: Resultscontrasting

confidence: 53%

Function of Metals and Supports on the Hydrodeoxygenation of Phenolic Compounds

Deepa

Dhepe

2014

ChemPlusChem

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“…There are several reports of the isomerization of eugenol catalyzed by alkalis in alcoholic solutions [28], by solid bases [29][30][31], and by metal complexes [32]. Catalysis by bases is used industrially to catalyze the conversion of eugenol to isoeugenol [29].…”

Section: Discussionmentioning

confidence: 99%

Upgrading of Lignin-Derived Compounds: Reactions of Eugenol Catalyzed by HY Zeolite and by Pt/γ-Al2O3

et al. 2011

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The conversion of eugenol (4-allyl-2-methoxyphenol), a compound derived from the lignin in woody biomass, was catalyzed by HY zeolite at 573 K and atmospheric pressure. The main products were isoeugenol and guaiacol, formed by isomerization and by deallylation, respectively. Substituted guaiacols with saturated sidechains (4-methylguaiacol, 4-ethylguaiacol, and 4-propylguaiacol) were also formed, by hydrogen transfer and alkylation reactions. The pseudo-first-order rate constant for the overall disappearance of eugenol was found to be 12.4 L (g of catalyst)/h. When the catalyst was Pt/c-Al 2 O 3 used in the presence of H 2 , significant hydrogenation of the propenyl side-chain took place, accompanied by isomerization, and hydrodeoxygenation. Under similar operating conditions, the reaction catalyzed by Pt/c-Al 2 O 3 in the presence of H 2 gave a higher eugenol conversion (X = 0.70) than the reaction catalyzed by HY zeolite (X = 0.11), primarily because of the dominant hydrogenation observed with the former catalyst. In the absence of H 2 as a co-reactant, the acidic c-Al 2 O 3 support in Pt/c-Al 2 O 3 evidently catalyzed all the classes of reactions catalyzed by HY zeolite.

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“…[12] Other examples are the isomerisation of allyl benzenes such as estragol or safrole, which are of great interest for the fragrance industry. [13,14] A wide range of isomerisation catalysts have been developed based on various metals such as Pd, [15][16][17] Ru, [18][19][20][21][22] Ti, [23][24][25] V, [26] Fe, [27][28][29] Rh, [30][31][32] Mo, [33] Ni, [34][35][36] etc., but also metal-free systems such as frustrated Lewis pairs. [37] One of the most active catalysts is the ruthenium-based "alkene zipper" developed by Grotjahn and co-workers.…”

Section: Introductionmentioning

confidence: 99%

Alkene Isomerisation Catalysed by a Ruthenium PNN Pincer Complex

Perdriau

Chang

Otten

et al. 2014

Chemistry A European J

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The [Ru(CO)H(PNN)] pincer complex based on a dearomatised PNN ligand (PNN: 2-di-tert-butylphosphinomethyl-6-diethylaminomethylpyridine) was examined for its ability to isomerise alkenes. The isomerisation reaction proceeded under mild conditions after activation of the complex with alcohols. Variable-temperature (VT) NMR experiments to investigate the role of the alcohol in the mechanism lend credence to the hypothesis that the first step involves the formation of a rearomatised alkoxide complex. In this complex, the hemilabile diethylamino side-arm can dissociate, allowing alkene binding cis to the hydride, enabling insertion of the alkene into the metal-hydride bond, whereas in the parent complex only trans binding is possible. During this study, a new uncommon Ru(0) coordination complex was also characterised. The scope of the alkene isomerisation reaction was examined.

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Selective double bond isomerization of allyl phenyl ethers catalyzed by ruthenium metal complexes

Cited by 50 publications

References 12 publications

Function of Metals and Supports on the Hydrodeoxygenation of Phenolic Compounds

Function of Metals and Supports on the Hydrodeoxygenation of Phenolic Compounds

Upgrading of Lignin-Derived Compounds: Reactions of Eugenol Catalyzed by HY Zeolite and by Pt/γ-Al2O3

Alkene Isomerisation Catalysed by a Ruthenium PNN Pincer Complex

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