Optimization of the Synthesis of SAPO-11 for the Methylation of Naphthalene with Methanol by Varying Templates and Template Content

Wang, Xiaoxiao; Zhang, Wei; Guo, Shaojun; Zhao, Lei; Xiang, Huimin

doi:10.5935/0103-5053.20130152

Cited by 13 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ratio of 2,6-/2,7-DMN is an essential parameter of alkylation . The ratios of 2,6-/2,7-DMN at varied WHSVs and temperatures appear in Figure .…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Methylation of Naphthalene with Methanol over the Al-Modified SiO₂ Zeolite Catalysts

Zhong,

Xu,

et al. 2024

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

2,6-Dimethylnaphthalene (2,6-DMN) is a crucial intermediate in the synthesis of poly(ethylene naphthalate), a heatresistant insulating material. The key to synthesizing 2,6-DMN is the development of highly active catalysts, which still remains challenging. Herein, bare SiO 2 and a series of Al-modified SiO 2 catalysts (denoted as Al-SiO 2 ) were successfully synthesized through a hydrothermal method using sodium metaaluminate as the Al source. The prepared catalysts were used for catalytic alkylation of naphthalene, and it was found that the Al-doped SiO 2 exhibited better catalytic activity than bare SiO 2 . The main reason is ascribed to the increased acid sites for Bronsted and Lewis acids with the incorporation of Al. Among the Al-modified SiO 2 samples, the amount of weak and total acidities was the highest for the 30Al-SiO 2 sample. In addition, the reaction conditions over this prepared catalyst were studied and optimized. The results showed that it exhibited the highest activity when the temperature was 300 °C and the weight hourly space velocity was 1 h −1 . Furthermore, density functional theory calculations showed that the doping of Al into SiO 2 enhanced the adsorption of methanol, resulting in a faster rate of formation of methoxylated material in the first step. Besides, methylation at the 6 position was slightly preferred compared to that at the 7 position, in line with the experimental results.

show abstract

“…The ratio of 2,6-/2,7-DMN is an essential parameter of alkylation . The ratios of 2,6-/2,7-DMN at varied WHSVs and temperatures appear in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…The ratio of 2,6-/2,7-DMN is an essential parameter of alkylation. 62 The ratios of 2,6-/2,7-DMN at varied WHSVs and temperatures appear in Figure 9. It was shown that the ratio was higher when the amount of Al doping was less.…”

Section: Catalytic Activity Evaluationmentioning

confidence: 99%

Methylation of Naphthalene with Methanol over the Al-Modified SiO₂ Zeolite Catalysts

Zhong,

Xu,

et al. 2024

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

show abstract

“…The catalytic efficiency of SAPO-11 in the stated processes is influenced by the strength and concentration of acid sites, crystal size, and characteristics of the porous structure. At present, some success has been achieved in the development of ways to regulate the concentration and localization of acid sites [ 18 , 19 , 20 , 21 , 22 , 23 ], as well as the crystal size and characteristics of the secondary porous structure [ 24 , 25 , 26 , 27 , 28 , 29 ]. At the same time, despite the advancements in synthesizing SAPO-11 silicoaluminophosphate, the crystallization mechanism remains insufficiently studied, knowledge of which will allow us to move to the directed control of the above-mentioned characteristics of these molecular sieves and the creation of more efficient catalysts based on them [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

Changing Template/Al2O3 Ratio in Reaction Gel—An Effective Way to Regulate Nature of Intermediate Phases and Properties of SAPO-11 Molecular Sieves during Crystallization

Agliullin,

Serebrennikov,

Kutepov

2024

Materials

View full text Add to dashboard Cite

A study has been conducted to investigate the formation of intermediate phases during the crystallization of SAPO-11 molecular sieves from reaction mixtures with a varying template (di-n-propylamine) DPA/Al2O3 ratio. It was found that changing the DPA/Al2O3 ratio from 1.0 to 1.8 in the initial reaction gels leads to the formation of different intermediate phases during crystallization into a SAPO-11 molecular sieve. It is shown that at the ratio template/Al2O3 = 1.0, an intermediate amorphous silicoaluminophosphate is formed; at 1.4, a mixture consisting of amorphous and layered phases forms; and at 1.8, a layered phase is present. A simple and innovative approach for controlling the morphology, size, and characteristics of primary crystals and the secondary porous structure in hierarchical SAPO-11 is proposed. The method is based on regulating the DPA/Al2O3 ratio in the reaction gel. The synthesized SAPO-11 molecular sieves with a hierarchical porous structure exhibited high selectivity in the hydroisomerization of n-hexadecane.

show abstract

“…By contrast, methylation of 2-methylnaphthalene (2-MN) or naphthalene (NA) with methanol over zeolite catalyst is regarded as a desirable process for the synthesis of 2,6-DMN. Various kinds of medium- or large-pore zeolites, such as HZSM-5, HSAPO-11, HZSM-11, HZSM-12, HBeta, HY, HMOR, HMCM-22 etc., ,− have been investigated. Generally, the large-porous zeolites show relatively high activity but low 2,6-DMN selectivity and 2,6/2,7-DMN ratio. ,,,, On the contrary, medium-porous zeolites (especially HZSM-5 or HSAPO-11) exhibit the high selectivity of 2,6-DMN and β,β-DMN but the relatively low conversion of 2-MN. ,− , These are directly related to the differences in the molecular diffusion and the porous shape selectivity between large and medium pore. − …”

Section: Introductionmentioning

confidence: 99%

New Process for 2,6-Dimethylnaphthalene Synthesis by Using C₁₀ Aromatics as Solvent and Transmethylation-Agentia: High-Efficiency and Peculiar Subarea-Catalysis over Shape-Selective ZSM-5/Beta Catalyst

Gong

Lian

et al. 2019

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

A new methylation (2-methylnaphthalene (2-MN) with methanol) process using low-value C 10 aromatics (C 10 A) as solvent and transmethylation-agentia was developed for the lower-cost synthesis of 2,6-dimethylnaphthalene (2,6-DMN), by using a ZSM-5/Beta composite catalyst. Especially, there is a peculiar subarea-catalysis over this catalyst due to both the reactant/product shape selectivity and the ingenious acidity design. Concretely, methylation (2-MN with methanol) and transmethylation (C 10 A with 2-MN) are catalyzed by the weak + medium + strong acid sites inside 12-ring pore and on the external surface of zeolites, while almost no transmethylation (but methylation and second shape-selective isomerization of fatter DMNs to β,β-DMN) occurs inside the smaller 10-ring pore (rejecting larger-molecular C 10 A) with mainly weak−medium acidity. Here, both the high-efficiency synergy of methylation with transmethylation and the meritorious isomerization incubated a 2-MN conversion of 52.98% and a 2,6-DMN yield of 11.01%. Our work may provide a promising model for the rational design of an excellent catalyst for a complicated reaction system.

show abstract

Optimization of the Synthesis of SAPO-11 for the Methylation of Naphthalene with Methanol by Varying Templates and Template Content

Cited by 13 publications

References 0 publications

Methylation of Naphthalene with Methanol over the Al-Modified SiO₂ Zeolite Catalysts

Methylation of Naphthalene with Methanol over the Al-Modified SiO₂ Zeolite Catalysts

Changing Template/Al2O3 Ratio in Reaction Gel—An Effective Way to Regulate Nature of Intermediate Phases and Properties of SAPO-11 Molecular Sieves during Crystallization

New Process for 2,6-Dimethylnaphthalene Synthesis by Using C₁₀ Aromatics as Solvent and Transmethylation-Agentia: High-Efficiency and Peculiar Subarea-Catalysis over Shape-Selective ZSM-5/Beta Catalyst

Contact Info

Product

Resources

About

Optimization of the Synthesis of SAPO-11 for the Methylation of Naphthalene with Methanol by Varying Templates and Template Content

Cited by 13 publications

References 0 publications

Methylation of Naphthalene with Methanol over the Al-Modified SiO2 Zeolite Catalysts

Methylation of Naphthalene with Methanol over the Al-Modified SiO2 Zeolite Catalysts

Changing Template/Al2O3 Ratio in Reaction Gel—An Effective Way to Regulate Nature of Intermediate Phases and Properties of SAPO-11 Molecular Sieves during Crystallization

New Process for 2,6-Dimethylnaphthalene Synthesis by Using C10 Aromatics as Solvent and Transmethylation-Agentia: High-Efficiency and Peculiar Subarea-Catalysis over Shape-Selective ZSM-5/Beta Catalyst

Contact Info

Product

Resources

About

Methylation of Naphthalene with Methanol over the Al-Modified SiO₂ Zeolite Catalysts

Methylation of Naphthalene with Methanol over the Al-Modified SiO₂ Zeolite Catalysts

New Process for 2,6-Dimethylnaphthalene Synthesis by Using C₁₀ Aromatics as Solvent and Transmethylation-Agentia: High-Efficiency and Peculiar Subarea-Catalysis over Shape-Selective ZSM-5/Beta Catalyst