Solvent-free synthesis of zeolite catalysts

Abstract

The most used method for preparation of zeolites is hydrothermal synthesis from silicate or aluminosilicate gels at temperatures in the range of 60-200 °C. Excess water used in the industrial process results in several issues, including high autogeneous pressure, low efficiency, pollution, etc. To solve these problems, several strategies have been developed. This review describes the solvent-free synthesis of zeolites. The combination of solvent-free synthesis and organotemplate-free synthesis can open the pathway to a highly sustainable zeolite synthesis protocol in industry. zeolites, solvent-free, sustainable

Vapor‐Phase Deposition and Modification of Metal–Organic Frameworks: State‐of‐the‐Art and Future Directions

“…When assessing the recent progresses in dry crystallization and vapor deposition of MOFs, the important role of mobility‐enhancing fluids during crystallization is evident. Interestingly, an equivalent role of such species has been identified in solvent‐free synthesis of microporous zeolites …”

“…Interestingly,a n equivalent role of such speciesh as been identified in solventfree synthesis of microporous zeolites. [56] MOF-CVD is ad isruptiven ew direction for the researcho n transformation of vapor deposited metal oxidest oM OFs, as it is the first MOF deposition procedure comprising only vapor processing steps. [8] The relatedo pportunities in terms of industry compatibility, reproducibility,a nd scalability are significant and numerous.…”

Mechanoenzymatic Transformations in the Absence of Bulk Water: A More Natural Way of Using Enzymes

“…Ultimately,q uantitative conversion into the dipeptide was achievedb yd oubling the enzyme loading, from 10 to 20 wt % relative to the substrates. The optimized conditions allowed variations on both the amino acid ester (12)a nd the amino acid amide (13), enabling synthesis of aw ides cope of dipeptides (14 a-14 h, 14 l-14 n, 14 p-14 s;S cheme 6B). The d-alanine methyl ester was not well tolerated by papain, leading to significantly lower yields (14 n), and d-phenylalanine phenyl ester did not react appreciably (e.g., 14 j, 14 o were not formed).…”

“…Solvent‐free (neat) chemical transformations have received a lot of attention in recent years in part for their potential to greatly decrease the amount of waste generated . One example is mechanochemistry (Figure ), now an established, powerful tool to conduct solvent‐free reactions, often reaching higher yields and/or faster rates than equivalent transformations in solution .…”

“…Solvent-free (neat) chemical transformations have received a lot of attention in recenty ears in part for their potential to greatly decrease the amounto fw aste generated. [9][10][11][12][13][14] One example is mechanochemistry ( Figure 1), now an established, powerful tool to conduct solvent-free reactions, often reaching higher yields and/orf aster rates than equivalent transformations in solution. [15][16][17] In addition, mechanochemicalt reatment, in the form of grinding, milling, extrusion, or acoustic mixing, has been shown to alter the selectivity of reactions and generate products unachievable by solution-based approaches.…”