Heterogeneous chlorination of formaldehyde with HCl in the presence of zeolite Y

Bresinska, I.; Drago, Russell S.

doi:10.1007/bf00764932

Cited by 2 publications

(2 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This proposal is consistent with earlier work on "salt occlusion" reported for simple inorganic salts such as NaCl, NaCN and NaI. [17][18][19][20]24] We have obtained strong evidence in support of an increase in the ion-pair association constant for occluded Meisenheimer complex. Thus, adsorption of a neutral Meisenheimer/Na + ion-pair complex, rather than a negative species, would take place.…”

Section: Wwwchemeurjorgsupporting

confidence: 92%

“…Only scarce precedents have described the presence of inorganic anions in zeolites. [17,18] For instance, CN À was adsorbed to form [Co(CN) 5 ] 2À in zeolite Y cages, [19,20] and I À has been demonstrated to be easily adsorbed [21][22][23] and even form charge-transfer complexes with incorporated viologen. [24] Manganate carbonyl salts have been used to induce thermal electron transfer in zeolite micropores.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Anionic Organic Guests Incorporated in Zeolites: Adsorption and Reactivity of a Meisenheimer Complex in Faujasites

Herance

Concepción

Doménech

et al. 2005

Chemistry A European J

View full text Add to dashboard Cite

Zeolites are suitable microporous hosts for positively charged organic species, but it is believed that they cannot adsorb organic anions. Pure Meisenheimer complex, derived from reduction of 2,4-dinitroaniline with NaBH4, was adsorbed inside faujasite cavities. Evidence for the internal incorporation of this negatively charged reaction intermediate comes from 1) XPS elemental analysis as a function of the depth of penetration into the particle, 2) the remarkable blue shift in lambda(max) of the Meisenheimer complex adsorbed on zeolite (ca. 470 nm) as compared to that in acetonitrile (580 nm) and 3) from the lack of reactivity with size-excluded hydride-acceptor reagents. Evidence is provided in support of an adsorption mechanism in which a neutral ion pair (alkali metal ion + Meisenheimer anion) is the actual species being adsorbed. In fact it appears that there is remarkable increase in the association constant for the ion-pair complex within the zeolite cavities as compared to DMF solution. Although this mechanism of adsorption as an ion-pair complex has precedents in the adsorption of some inorganic salts, what is novel is the notable increase in the stability and persistence of the Meisenheimer anion (a anionic reaction intermediate) as a result of zeolite inclusion. Adsorbed Meisenheimer complex exhibits much lower reactivity towards electron acceptors, oxygen, and water. Cyclic voltammetry of zeolite-modified electrodes reveals for the Meisenheimer complex adsorbed on LiY a reversible redox peak that is not observed in solution and has been interpreted as arising from site isolation and stabilisation of the electrochemically generated species.

show abstract

Section: Wwwchemeurjorgsupporting

confidence: 92%