Low temperature IR spectroscopy

Pyrolysis of o-hydroxybenzyl alcohol at 550 °C resulted in the formation of simple o-quinone methide, which was directly observed using low-temperature IR spectroscopy.122 Pyrolysis of chroman (Scheme 33) at 400-600 °C gives the simple o-quinone methide and ethene along with o-cresol, benzofuran, and styrene.123,124 The o-quinone methide was trapped with alkenes to form Diels Adler adducts, with hydrogen gas or hydrogen atom to form o-cresol, or underwent a further pyrolysis to CO and fulvene. 

Low-temperature photolysis or gas-phase thermolysis followed by low-temperature quenching of 50 provided 51, as shown by low-temperature IR spectroscopy <1996T1965>. 

Low temperature IR spectroscopy of CO as a test molecule provides means to display the difference of surface properties of Ti-containing adsorbents. Two kinds of TS-1 zeolite samples, which have identical structure and slightly different amount of residual alkali cations, characterized by this method, show great dissimilarity in the amount of acidic OH groups, Lewis acid sites of different strength, or of the reduced Ti atoms. Thus, the method could really be used as a rapid test for the surface properties of metal containing zeolites. 

In this paper, we introduce the developed in situ low temperature IR spectroscopy and report preliminary IR spectra of thin methane hydrate film. 

We have developed an in situ low temperature IR spectroscopy using a commercial thermostatic stage and nitrogen gas flow system to avoid frost formation on experimental system. 

Disubstituted 5-isoxazolones 169 (R R = alkyl or aryl) are converted into acetylenes 170 by the combined action of sodium nitrite and iron(II) sulphate in aqueous scetic acid a plausible mechanism is shown in equation 24 . Aminoacetylene (172) has been produced by flash-vacuum pyrolysis of the isoxazolones 171 (R=Me or Ph) it was observed by low-temperature IR spectroscopy and by its collision activation mass spectrum (CAMS). Aminoacetylene is also formed by pyrolysis of the derivative 173 of Meldrum s acid the product, an equilibrium mixture of the ketenes 174 and 175, decomposes above 680°C to aminoacetylene ". ... 

Mekhemer, G.A.H., and Zaki, M.I., Low-temperature IR spectroscopy of CO adsorption on calcined supported ceria Probing adsorbed species and adsorbing sites. Adsorpt. Sci. Technol., 15(5), 377-390 (1997). 

There was IR evidence (vCO, VN2O) for the formation of CpMn(C0)2(N20) by UV photolysis of CpMn(CO)3 in liquid or near-critical N2O at room temperature. Low-temperature IR spectroscopy was used to detect CpMn(CO)2(tol-uene), from the photolysis of CpMn(CO)3 -I- toluene/hexane. Femtosecond-scale time-resolved IR studies (vCO) have been reported to give information on the mechanism of ring-slip in (ri -C5Cl5)Mn(CO)5. ... 

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