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Ozone adsorption has been studied by IR spectroscopy at low temperature. Although alumina is more acidic than TiO2, as shown by pyridine adsorption, IR spectroscopy did not detect O3species adsorbed on strong Lewis Al3+sites. However, O3decomposition occurred and pyridine specific poisoning evidenced that such sites were involved in the decomposition. Quantum chemistry calculations confirmed such a result and specified that the remaining O(1D) resulting from the decomposition, in addition to physisorbed O2, was attached to the aluminum ion constituting the Lewis sites. The oxygen molecules would then gradually be desorbed.

Adsorption of CH3SH and CH3OH on activated NaX and NaY zeolites has been studied by IR spectroscopy. Only NaX is able to provoke the dissociative adsorption of CH3SH at room temperature and that of CH3OH at 623 K. Results are discussed taking into account sodium cations in the SIII position.

Reactivity of surface methoxides, ethoxides, 2-propoxides and tert-butoxides on thoria with water, an alcohol, and on heating has been studied by FT-IR spectroscopy. It was shown that at least two surface alkoxides are formed; simple (I) and the bridged (II) ones. Structure II can be hydrolyzed or alcoholyzed to structure I, and vice versa, structure I can form structure II upon heating. Alkoxides with β-hydrogens decompose to the corresponding alkenes. As indicated by kinetic data, the reaction scheme can be assumed as consecutive: I→II→alkene.

FT-IR spectroscopy has been applied in a study of methanol adsorption on MINaY zeolites (M=Li, K, Rb, Cs). Coordinatively and/or hydrogen bonded methanol was registered in the temperature range 300–473 K. Dehydration of methanol to dimethyl ether occurred at 573 and 623 K. It was found that the activity of the catalyst for methanol dehydration strongly depends on the kind of alkali metal cation, and well correlates the IR data relative to methanol adsorption.

FTi.r. spectroscopy has been applied in studying the reaction between methanol and hydrogen sulfide on NaX and NaY zeolites. Hydrogen-bonded methanol and methoxy and carbonate species were found on both of the zeolites after methanol adsorption. Pyrrole and pyridine preadsorption experiments have shown that methanol is chemisorbed on basic and/or cationic sites on the zeolites used. H2S is adsorbed on the same sites. In the reaction between methanol and hydrogen sulfide on sodium zeolites methoxy species or HS−ions are involved. Carbonate species can also react with H2S producing hydrogenthiocarbonates or thiocarbonates. However, this reaction does not play any role in the interaction between CH3OH and H2S under the conditions used.

Two zeolites were coked using cyclohexene at 620 K; one had a low Si/Alf ratio (HY), the other was ultrastabilized (HYS). It was found that oxygen regeneration occurred at 770 K or above, whereas ozone was effective at 450 K or less,e.g. under conditions such that the HY sample was still thermally stable.

Low-temperature CO adsorption on TiO2 (anatase) has been investigated by FTIR spectroscopy on (i) a pure sample, (ii) a sample on which the sites for CO adsorption at room temperature are blocked by ammonia, and (iii) anatase whose surface is covered by ammonia. Adsorption of small amounts of CO at 100 K on anatase leads to the appearance of two bands at 2210 and 2192 cm^-1 due to CO adsorbed on two kinds (α and β‘, respectively) of Ti⁴⁺ sites (the same species are also observed when adsorbing CO at room temperature). The increase of the introduced CO amount involves sites (β‘‘-sites) that are inert at room temperature. The CO molecules adsorbed on β‘‘-sites interact with CO molecules preadsorbed on β‘ sites, as a result of which the two adsorption forms produce a common absorption band whose maximum is shifted to 2179 cm^-1 at higher coverage. With increasing amount of adsorbed CO, one more kind (γ) of Ti⁴⁺ site with very weak acidity is detected, the corresponding absorption band being at 2165 cm^-1. Under CO equilibrium pressure two additional reversible adsorption forms appear:  CO H-bonded to surface hydroxyl groups (ν(CO) at 2155 cm^-1) and physically adsorbed CO (band at 2138 cm^-1). Simultaneously with the appearance and increase in intensity of the band at 2155 cm^-1, a broadening and shift by about −115 cm^-1 of the bands for the surface hydroxyl groups occur. Adsorption of a ¹³CO shows that the shifts of the bands at 2210 and 2192 cm^-1 are mainly of a static type (−4 and −17 cm^-1, respectively), the dynamic components being only +4 cm^-1 for the β-carbonyls and not measurable for the α-carbonyls. CO adsorption on reduced anatase indicates the formation of the same types of carbonyls. However, in this case, part of the introduced CO probably dissociates and oxidizes the Ti³⁺ ions into Ti⁴⁺. Low-temperature CO adsorption on anatase on which the sites for CO adsorption at room temperature (the α and β‘ sites) are preliminary blocked by ammonia leads to the formation of carbonyls on β‘‘ and γ sites (ν(CO) at 2177 and 2156 cm^-1, respectively), as well as of CO adsorbed on OH groups and physically adsorbed CO. In this case the shift of the OH stretching modes is still −115 cm^-1. Low-temperature CO adsorption on anatase fully precovered with ammonia shows the appearance of weakly bound forms only:  a part of the carbonyls on γ-sites (ν(CO) shifted to 2151 cm^-1), CO adsorbed on hydroxyl groups, and physically adsorbed CO. However, in this case the shift of the ν(OH) stretching modes is only −65 cm^-1. The nature of the different kinds of active sites for adsorption of ammonia and CO on anatase is discussed.

A Ru/TiO2(anatase) sample prepared by ion-exchange was studied by TPR and FTIR spectroscopy of CO adsorbed at different temperatures. Two kinds of Run+species, differing in their reducibility, are present on the sample surface. The IR spectra of the sample and of CO adsorbed reveal the existence of a RuO2-like phase and Run+(1 ≤ n ≤ 3) cations. The supported ruthenium is completely reduced to Ru0after treatment with hydrogen at 523 K. Simultaneously, a large part of the initial anatase sites are liberated for exchange. Therefore, a second ion-exchange of Ru/TiO2is possible which allows to double ruthenium concentration. Low-temperature CO adsorption on the reduced Ru/TiO2catalyst reveals the existence of Ru0sites as well as different sites typical of the bare titania. At temperatures close to the ambient one, CO interacts with the Ru0clusters causing disruption of some Ru–Ru bonds and increase in dispersion of ruthenium particles. At higher temperatures, CO dissociates on particular Ru0sites, thus oxidizing some Ru0atoms to Run+ions. Subsequently, Run+(CO)3species are formed after adsorption of additional CO molecules on these latter species. Simultaneously, the titania sites that have been liberated during the reduction are re-occupied. On the Ru/TiO2catalyst whose dispersion has been modified by CO contact, further reduction with hydrogen at 523 K leads to a new drop of the metal dispersion (similar to that of freshly reduced catalyst) showing that the metal sintering/increase in dispersion are reversible effects. When CO adsorption is performed on an oxidized catalyst, both Run+(CO)3and Rum+(CO)2species are formed on the surface. All these phenomena are also observed on the Ru/TiO2(anatase) catalyst prepared by impregnation. The results differ only in some quantitative values.

Mastertool MT8 is a new dry phototool for the production of printed circuit boards, which represents a completely new technology. MT8 is not sensitive to daylight, is free of silver and inherently environmentally safe as the material does not contain any toxic ingradients, no processing chemicals are required and no waste arises. For imaging, the nontransparent thin bismuth layer of MT8, embedded between polymers, is agglomerated into beads through IR laser radiation, making this area optically transparent. Light and electron microscopy as well as Xray diffractometry are used to characterise the composition of the material and the details of the recording processes. Based on finite element modelling, it was possible to interpret theoretically the experimentally determined dependence of the sensitivity on the recording speed. Understanding these material properties enables plotter optimisation for MT8.

Comparative adsorption of CH316OH and CH318OH on thoria shows the formation of four types of methoxy species resulting from methanol O−H dissociation. Species I, characterized by the highest ν(C−O) wave-number, reacts with CO2 at room temperature, leading to the formation of methyl carbonate species while the others are almost unreactive. Species I is considered as monodentate, the others as bi or tridentate. Their structure is related to the local arrangement of the exposed faces.

Ozone (O3) adsorption on CeO2 pretreated under different conditions and characterized by low-temperature CO adsorption was studied by Fourier transform infrared (FTIR) spectroscopy at 77−300 K. Preliminary exposure to CO2, pyridine, acetonitrile, or methanol at 293 K or to CO at 77 K, as well as adsorption of ¹⁸O substituted O3 were used to clarify the nature of adsorption sites and the structure of the surface species. In addition to physisorption and weak H-bonding with the most acidic OH groups of the ceria surface, O3 forms coordinate complexes with two kinds of Lewis acid sites. These complexes have the bands of the ν1 and ν3 modes of O3 at 1096 and 1018−1015 cm^-1, or 1104 and 1012−1008 cm^-1, respectively. The coordinated O3 molecule is no longer symmetric but is bound to a surface Ce⁴⁺ ion via one of its terminal oxygen atoms. Basic surface sites of the samples pretreated at 773 K account for O3 decomposition, which occurs almost explosively at 77 K but could be inhibited if O3 adsorption is performed from the solution in liquid oxygen. Formation of ozonide O3^- (bands at 792 and 772 cm^-1) and superoxide O2^- (band at 1128 cm^-1) species was detected; these species are believed to be the intermediates of O3 decomposition on basic sites. On ceria, O3 does not react at 77 K with adsorbed CO, but ozonolysis of surface methoxy groups proceeds slowly, leading to a formate surface species.

The reactivity towards O3 of the different species formed from phenol adsorption on silica and ceria has been studied using IR spectroscopy by increasing the temperature from 77 K. It clearly appeared that on silica H-bonded phenol species were more reactive than phenoxy species, whereas on ceria monodentate phenoxy species were more active than bidentate species. Intermediate products of phenol oxidation were characterized by bands between 1800 and 1600 cm-1, that at 1750 cm-1 being probably due to the formation of a carboxylic acid.

Measles morbidity data were collected during 982ndash;1983 through a network of sentinel general practitioners. The annual incidence rate of the disease in the country was 80.3 per 10000 population with most of the cases seen between 2 and 6 years of age. Complications were encountered in 13.8% of all cases. Emphasis is put on developing a strategy for immunization against measles on a nationwide scale.