Tuning molecular structure of tertiary amine catalysts for glucose isomerization

Deshpande, Nitish; Cho, Eun Hyun; Spanos, Alexander; Lin, Lu; Brunelli, Nicholas A.

doi:10.1016/j.jcat.2019.02.025

Cited by 26 publications

(17 citation statements)

References 40 publications

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“…The micropore volume of these silica materials is of particular interest in the present work and is determined from the nitrogen physisorption data using the t‐plot method. The surface area and pore volume of REG SBA‐15 (930 m 2 /g and 1.18 cm 3 /g, respectively) are consistent with previous reports . The micropore volume of REG SBA‐15 is calculated to be 0.08 cm 3 /g.…”

Section: Resultssupporting

confidence: 89%

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Impact of surface loading on catalytic activity of regular and low micropore SBA‐15 in the Knoevenagel condensation

2019

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The mesopores of SBA‐15 are well‐suited for immobilizing catalytic aminosilanes for converting substrates for fine chemicals, but these materials have micropores that could impact the observed reaction rate of immobilized catalysts. Materials are synthesized with conventional methods that produce micropores (Regular Micropore SBA‐15; REG) and compared to materials with limited to no micropore volume (NMP SBA‐15). These materials are functionalized with aminosilanes for testing in the Knoevenagel condensation. For low amine loadings, NMP materials have a higher observed reaction rate compared to REG materials, achieving twice the conversion in the same time. As the surface density increases, the reaction rate for NMP materials decreases since organosilane functionalization consumes surface silanols that interact cooperatively with the amine. Regardless of surface density, the NMP materials have higher observed reaction rate than the REG materials. These results demonstrate the importance of reducing micropore volume to create highly active catalytic materials.

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Section: Resultssupporting

confidence: 89%

“…The synthesis of SBA‐15 is achieved using methods reported previously . Briefly, an aqueous solution of hydrochloric acid is used to dissolve Pluronic P123 with stirring at 40°C.…”

Section: Experimental Methodsmentioning

confidence: 99%

Impact of surface loading on catalytic activity of regular and low micropore SBA‐15 in the Knoevenagel condensation

2019

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“…This observation accords well with the effect of base strength of IL catalyst, where too great strength of base resulted in higher glucose conversion but lower yield and selectivity of fructose (Table 1, entries 10–15). It is well known that, in a homogeneously catalytic process, higher catalyst dosage indicates greater catalytic active center, [31] thus, an improved glucose conversion and fructose yield were shown at higher dosage of IL [TMG]Pro. However, the side‐reactions, for example, the degradation of sugar, the formation of Humins, and the retro Aldol reactions would also be enhanced at the excessive base centers [32] .…”

Section: Resultsmentioning

confidence: 99%

Aqueous Isomerization of Glucose to Fructose Catalyzed by Guanidinium Ionic Liquids

Chen

Huang

et al. 2022

ChemistrySelect

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The isomerization of glucose to fructose is the rate determining step in many techniques for chemo‐catalytic conversion of cellulosic biomass to highly value‐added biochemicals. However, current techniques are generally challenging by poor process efficiency, low fructose yield and selectivity, etc. Therefore, the exploitations of novel catalytic systems for the efficient isomerization of glucose are important and highly desired. Herein, a series of biodegradable guanidinium ionic liquids were synthesized and employed in the selective isomerization of glucose to fructose. The results demonstrated that the performance of the isomerization of glucose was significantly influenced by the basic strength of the ionic liquids and the reaction conditions involving catalyst dosage, reaction temperature, time, and solvent. At the optimized conditions of 80 °C for 30 min, an impressive fructose yield of 34.1 % could be obtained in the presence of tetra methyl guanidinium proline ([TMG]Pro). Furthermore, the kinetic behavior of the process was further studied, and the apparent activation energy was 57±2 KJ/mol, which is lower than most current base‐catalyzed glucose isomerization systems. Moreover, the results of isotope labeling experiments showed that this aqueous isomerization of glucose was proceeded via a deprotonation mechanism. Therefore, this work provides a new insight on the selective isomerization of glucose.

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“…The bulky groups prohibit the interaction between the amine centers and silica surface, boosting the catalytic activity. Therefore, there are certain key factors to keep in mind before anchoring the homogeneous catalyst on silica during the preparation of heterogeneous catalysts …”

Section: Applications and Advantages Of Fs‐based Catalystsmentioning

confidence: 99%

Functionalized Silicas for Metal‐Free and Metal‐Based Catalytic Applications: A Review in Perspective of Green Chemistry

Antony

Marimuthu

Yang

et al. 2019

The Chemical Record

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Heterogeneous catalysis plays a key role in promoting green chemistry through many routes. The functionalizable reactive silanols highlight silica as a beguiling support for the preparation of heterogeneous catalysts. Metal active sites anchored on functionalized silica (FS) usually demonstrate the better dispersion and stability due to their firm chemical interaction with FSs. Having certain functional groups in structure, FSs can act as the useful catalysts for few organic reactions even without the need of metal active sites which are termed as the covetous reusable organocatalysts. Magnetic FSs have laid the platform where the effortless recovery of catalysts is realized just using an external magnet, resulting in the simplified reaction procedure. Using FSs of multiple functional groups, we can envisage the shortened reaction pathway and, reduced chemical uses and chemical wastes. Unstable bio‐molecules like enzymes have been stabilized when they get chemically anchored on FSs. The resultant solid bio‐catalysts exhibited very good reusability in many catalytic reactions. Getting provoked from the green chemistry aspects and benefits of FS‐based catalysts, we confer the recent literature and progress focusing on the significance of FSs in heterogeneous catalysis. This review covers the preparative methods, types and catalytic applications of FSs. A special emphasis is given to the metal‐free FS catalysts, multiple FS‐based catalysts and magnetic FSs. Through this review, we presume that the contribution of FSs to green chemistry can be well understood. The future perspective of FSs and the improvements still required for implementing FS‐based catalysts in practical applications have been narrated at the end of this review.

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Tuning molecular structure of tertiary amine catalysts for glucose isomerization

Cited by 26 publications

References 40 publications

Impact of surface loading on catalytic activity of regular and low micropore SBA‐15 in the Knoevenagel condensation

Impact of surface loading on catalytic activity of regular and low micropore SBA‐15 in the Knoevenagel condensation

Aqueous Isomerization of Glucose to Fructose Catalyzed by Guanidinium Ionic Liquids

Functionalized Silicas for Metal‐Free and Metal‐Based Catalytic Applications: A Review in Perspective of Green Chemistry

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