Selective O-methylation of catechol using dimethyl carbonate over calcined MgAl hydrotalcites

Jyothi, T. M.; Raja, Thirumalaiswamy; Talawar, M. B.; Rao, B.S.

doi:10.1016/s0926-860x(00)00839-5

Cited by 59 publications

(28 citation statements)

References 13 publications

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“…In particular, all solids show a desorption peak at temperatures of ∼100°C, which can be attributed to the interaction of CO 2 with sites of weak basic strengths. [20][21][22] It has been proposed in the literature that these sites correspond to OH -groups on the surface (see Bolognini et al 21 and references therein). This peak, which is observed for all the examined solids, is the only one present on the γ-alumina surface.…”

Section: Resultsmentioning

confidence: 99%

“…The patterns were obtained using Cu KR radiation (λ ) 1.5418 Å) at 40 kV and 40 mA; the diffraction angle 2θ was scanned at a rate of 2°/ min. Finally, the basic properties of the solids were determined using the temperature-programmed desorption of carbon dioxide (CO 2 -TPD), which was used as the probe molecule [20][21][22] in a TPD/R/O 1100 TermoQuest instrument. The catalysts were degassed by heating, at 500°C, under helium and then treated, at room temperature, with the probe gas stream.…”

Section: Catalyst Characterizationmentioning

confidence: 99%

See 1 more Smart Citation

Transesterification of Soybean Oil to Biodiesel by Using Heterogeneous Basic Catalysts

Serio¹,

Ledda²,

Cozzolino³

et al. 2006

Ind. Eng. Chem. Res.

397

212

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Biodiesel production has increased greatly in recent years, because of the less-detrimental effects of this fuel on the environment, compared to a conventional diesel obtained from petroleum. This work investigates the possibility of using MgO and calcined hydrotalcites as catalysts for the transesterification of soybean oil with methanol. The achieved experimental data show a correlation not only with the catalysts basicity, but also with its structural texture. However, the structural texture of the examined catalysts is dependent on both the precursor and the preparation method. At least four different types of basic sites have been individuated on the surface of MgO and calcined hydrotalcite catalysts. The strongest basic sites (super-basic) promote the transesterification reaction also at very low temperature (100°C), while the basic sites of medium strength require higher temperatures to promote the same reaction. Ultimately, all the tested catalysts are resistant to the presence of moisture in the reaction environment.

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Section: Resultsmentioning

confidence: 99%

Section: Catalyst Characterizationmentioning

confidence: 99%

Transesterification of Soybean Oil to Biodiesel by Using Heterogeneous Basic Catalysts

Serio¹,

Ledda²,

Cozzolino³

et al. 2006

Ind. Eng. Chem. Res.

397

212

View full text Add to dashboard Cite

show abstract

“…The selectivity for Calkylates showed the opposite trend. This suggests that C-alkylates are formed by the subsequent isomerisation of O-alkylates formed initially over sulphated zirconia [7]. Once again, the maxima observed at 5 wt.% SZ catalysts reflect the strong stabilization effect of the tetragonal form of zirconia.…”

Section: Resultsmentioning

confidence: 87%

“…One also observes that at lower/weaker acidity (i.e.< 5 wt.% SO 4 2-), the reaction favours the formation of guaiacol (O-alkylation) while higher/stronger acidity favours C-alkylated products. The type of alkylating agent also plays an important role [7]. The influence of dimethyl carbonate (DMC), along with CH 3 OH, on the catechol activity and selectivity over the 5 wt.% SZ catalyst is shown in Table 2.…”

Section: Resultsmentioning

confidence: 99%

“…In recent years, several solid acid catalysts have been tried out for various alkylation reactions. Some of the solid acid catalysts studied for the title reaction were metal oxides [4][5][6][7][8][9], phosphates [10,11], ammonium metatungstate [12] and zeolites [13]. However, information on the alkylation of catechol over sulphatemodified zirconia (SZ) is rather limited [14,15] The surface areas of zirconia and sulphated zirconia samples were measured by Quantasorb AS-1 using N 2 as a probe molecule.…”

Section: Introductionmentioning

confidence: 99%

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Alkylation of catechol with methanol to guaiacol over sulphate-modified zirconia solid acid catalysts

Vishwanathan

Gajula

Rajesh

et al. 2007

React Kinet Catal Lett

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1,2,3‐Trimethoxypropane and Glycerol Ethers as Bio‐Sourced Solvents from Glycerol. Synthesis by Solvent‐Free Phase‐Transfer Catalysis and Utilization as an Alternative Solvent in Chemical Transformations

et al. 2013

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Abstract1,2,3‐Trimethoxypropane (2), 1‐alkoxy‐2,3‐dimethoxy‐propanes, and 1‐aryloxy‐2,3‐dimethoxypropanes were prepared in good yields and selectivity by solid–liquid phase‐transfer catalysis in the presence of an inorganic base and an ammonium salt as the phase‐transfer catalyst with no additional solvent. No heating was required, and the synthesis was easily performed under atmospheric pressure on a 150 g scale. For the preparation of 2, the conversion of glycerol was complete and the selectivity for the expected glycerol trimethylether was above 95 %. This product was utilized as a solvent in organic reactions such as transesterifications between glycerol and vegetable oil, organometallic reactions (Grignard‐ and Barbier‐type reactions), carbon–carbon coupling reactions (Suzuki, Sonogashira, Heck), and in etherification reactions by dehydrogenative alkylation. The solvent showed interesting properties for the solubilization of polymers.

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Selective O-methylation of catechol using dimethyl carbonate over calcined MgAl hydrotalcites

Cited by 59 publications

References 13 publications

Transesterification of Soybean Oil to Biodiesel by Using Heterogeneous Basic Catalysts

Transesterification of Soybean Oil to Biodiesel by Using Heterogeneous Basic Catalysts

Alkylation of catechol with methanol to guaiacol over sulphate-modified zirconia solid acid catalysts

1,2,3‐Trimethoxypropane and Glycerol Ethers as Bio‐Sourced Solvents from Glycerol. Synthesis by Solvent‐Free Phase‐Transfer Catalysis and Utilization as an Alternative Solvent in Chemical Transformations

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