Novel titration method for surface-functionalised silica

Hofen, Kai; Weber, Siegfried; Chan, Chiu; Majewski, Peter

doi:10.1016/j.apsusc.2010.10.025

Cited by 11 publications

(7 citation statements)

References 7 publications

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“…Since the concentration of amino groups was quantified by back titration with 0.1 mol/L HCl, this possibly remained after neutralization. Therefore, not all amino groups could be neutralized due to the incomplete dissociation of weak base amino groups . This result implied that the alkali active could not be represented by all grafted amino groups.…”

Section: Resultsmentioning

confidence: 99%

“…Temperature‐programmed desorption of carbon dioxide (CO 2 ‐TPD) analysis was performed in a TPD/R/O 1100 analyzer, and used to study the basic strength of different amines functionalized on zeolite Y catalysts. The concentration of amino groups in the fresh catalyst and each cycle of spent catalyst was quantified by back‐titration, as previously reported . In brief, 0.2 g of the grafted catalysts, 1 g sodium chloride, and 8 mL water were mixed for 24 h. The quantity of released hydroxyl groups was then determined by titration with 0.1 mol/L HCl, using phenolphthalein as the indicator.…”

Section: Methodsmentioning

confidence: 99%

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Inorganic‐organic hybrid material based on amine‐functionalized zeolite Y: A study of catalytic activity in transesterification

et al. 2016

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Three different structures of amine compound, 3‐aminopropyl trimethoxysilane (N1), N‐[3‐(trimethoxysilyl)propyl] ethylenediamine (N2), and N‐[3‐(trimethoxysilyl)propyl] diethylenetriamine (N3), functionalized on zeolite Y, were used to enhance catalyst lifetime in the transesterification reaction. The presence of amine compound was confirmed by FTIR. Moreover, the grafting percentage of amine on zeolite Y was also considered, since it affected the basicity and basic strength of the catalyst. The catalytic activity testing for transesterification of glyceryl tributyrate (GTB) and methanol was carried out in an autoclave reactor at reaction conditions of 30:1 molar ratio of methanol to GTB and a catalyst loading level of 0.35 g/g (35 mass% of GTB). The highest methyl butyrate production per active site was obtained by N3, due to its having the highest basic strength. The highest methyl butyrate yield was given by N1, due to its having the highest amino group concentration (basicity). Therefore, the catalytic activity, in terms of methyl butyrate yield and methyl butyrate production per active site, was affected by both basic strength and basicity. The reusability of the catalysts showed that the methyl butyrate yield slightly declined to ∼13.8 % yield after four cycles, but the methyl butyrate production per active site remained constant across four cycles.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Inorganic‐organic hybrid material based on amine‐functionalized zeolite Y: A study of catalytic activity in transesterification

et al. 2016

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“…The investigation of adsorbent has been focused on synthesis and application. Sulfonato silica can be formed by grafting method [3][4]. Researches about sol-gel method besides the grafting one have been reported, i.e.…”

Section: Introductionmentioning

confidence: 99%

ADSORPTION OF Mg(II) AND Ca(II) ON DISULFONATO-SILICA HYBRID

Azmiyawati¹,

Nuryono²,

Narsito³

2012

Indones. J. Chem.

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Adsorption of Mg(II) and Ca(II) on disulfonato-silica hybrid (DSSH) in the aqueous solution has been studied. The hybrid was synthesized by sol-gel process with sodium silicate solution from rice hull ash, chloroprophyltrimethoxysilane (CTS) and 4-amino-5-hydroxy-naphtalene-2,7-disulfonic acid monosodium salt (ANSNa) as silica source, cross linker and active group, respectively. Sodium silicate solution was reacted with CTS and ANSNa that were added dropwise. Adsorption of magnesium and calcium ions on DSSH was carried out in a batch system. Solution pH significantly affected magnesium and calcium adsorption and the optimum condition was obtained at pH = 6. The synthesized DSSH showed a high adsorption capacity of 0.0844 mmol/g and 0.1442 mmol/g for Mg(II) and Ca(II), respectively. The adsorption isotherm obtained with Langmuir isotherm model gives the negative values of ΔG°, i.e. -23.334 kJ/mol and -22.757 kJ/mol for Mg(II) and Ca(II), respectively, indicating the spontaneous process of adsorption. Kinetic studies showed that the adsorption of Mg(II) and Ca(II) ions onto HDSS follows the pseudo-second-order kinetics.

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“…The titration of particles to calculate their surface charge density was applied widely in the past [19,20]. A defined amount of particles is suspended in 0.01 M NaOH to completely deprotonate the carboxyl groups.…”

Section: Titration Methodsmentioning

confidence: 99%