Isopropanol decomposition

Two different processes were used in this study to prepare transition metal (M Fe, Ni, Co) based salts of molybdophosporic acid. They were characterised by BET method, XRD and UV-Vis and IR spectroscopies and tested in isopropanol decomposition at 150°C. The nature of both the added transition metal ion and the synthesis method has an influence on physic-chemical and catalytic properties of solid. 

The study of the two (MPMol2)b and (MPMol2)b series salts (M Fe, Ni, Co) shows that their physic-chemical properties (XRD and BET) were different. The catalytic test of isopropanol decomposition at 150°C, shows the strong acidic character of the (MPMol2)b series and the acid and redox character of the (MPMol2)a. 

Isopropanol Decomposition on ZnO, a Reaction Without the Transition of Oxygen... 

Fig. 13. Influence of UV irradiation and age of ZnO catalyst on activation energies of isopropanol decomposition. Open symbols, light closed symbols, dark...

Interesting supports are the polymeric materials, notwithstanding their thermal instability at high temperatures. In the electrocatalysis field, the use of polypyrrole, polythiophene and polyaniline as heteropolyanion supports was reported [2]. The catalytically active species were introduced, in this case, via electrochemical polymerization. Hasik et al. [3] studied the behavior of polyaniline supported tungstophosphoric acid in the isopropanol decomposition reaction. The authors established that a HPA molecular dispersion can be attained via a protonation reaction. The different behavior of the supported catalysts with respect to bulk acid, namely, predominantly redox activity versus acid-base activity, was attributed to that effect. 

The catalytic activity of alkali metal oxide clusters encapsulated in the zeolitic cages of faujasite has been tested in different reactions catalyzed by basic sites, e. g. olefin isomerization [75,77], isopropanol decomposition [67,68], and Knoe-venagel condensation [73,74,78]. 

Gervasini, A., Fenyvesi, J., and Auroux, A. Study of the acidic character of modified metal oxide surfaces using the test of isopropanol decomposition. Catal Lett. 1997, 43, 219-228. 

The measurement of the activity in a specific catalytic reaction, such as isopropanol decomposition or butene isomerization is also often used in the field. Catalysts may, for example, be characterized by their ability to dehydrate isopropanol molecules into propene, or to dehydrogenate them in acetone. The former reaction tests their acidity and the latter their basicity (Ai, 1977 Cunningham et al., 1981 Nollery and Ritter, 1984 Tanabe et al., 1989 Gervasini and Auroux, 1991). 

Place in the flask 2 g. of benzophenone, 15 ml. of isopropanol and 2 5 g. of aluminium isopropoxide. This mixture has now to be heated gently under reflux so that the temperature registered by the thermometer in the column does not exceed 80°, i.e., so that only acetone distils. For this purpose, the flask should preferably be heated in an oil-bath direct heating, even over an asbestos sheet, may cause local overheating and decomposition the use of a water-bath on the other hand may make the column undesirably damp. 

Purified by recrystn from aqueous EtOH or MeOH or aqueous NH3 + EtOH or isoPrOH. Also recrystd from aqueous ammoniacal soln at pH 10.5 (lOOmg/mL) by diluting with 5 volumes of isopropanol and then adjusting to pH 6 with acetic acid. An aqueous soln buffered to pH 10 with Na2C03 can be stored in a refrigerator for 1 week without decomposition. UV Xma, 226nm (/ij 4.02). The tartrate salt has m 165-166° (dec), 166-168° (dec), and [ag -41° (c 0.7, H2O). [Stammer et al. J Am Chem Soc 79 3236 7959 UV Kuehl J Am Chem Soc 77 2344 7955.]... 

A solution of 5 grams of (3-hydroxyphenyl)ethyl dimethylammonium hydroxide in about 200 cc of water was neutralized with dilute hydrochloric acid. On concentration to dryness in vacuo, (3-hydroxyphenyl)ethyl dimethylammonium chloride crystallized. The compound was recrystallized from isopropanol MP 162° to 163°C (with decomposition). 

On the addition of ethereal hydrogen chloride to a solution of the base in isopropanol and recrystallization from anhydrous ethanol of the salt formed, there is obtained 3-dimethyl-sulfamovl-10-(2-dimethvlaminopropyl)phenthiazine hydrochloride (2.1 grams), MP 214°C with decomposition. After dissolving the product in anhydrous ethanol and adding meth-anesulfonic acid there is obtained fonazine mesylate. 

The characteristics of this product are as follows. It is a pale yellow, nonodorous, slightly bitter, crystalline powder, very soluble in water (>1.5 g/cc), soluble in methanol and formamide, slightly soluble in ethanol and isopropanol, insoluble in ether, benzene and chloroform MP 162° to 163°C with decomposition uncorrected). 

To a solution of 18.9 grams (0.166 mol) n-heptaldehyde in 25 ml of isopropanol is added, with stirring, a solution of 19,1 grams (0.166 mol) of 1-aminohydantoin in 110 ml water acidified with concentrated HCI. The heavy white precipitate formed is filtered and washed, until acid free, with small amounts of water and ether. The yield of N-(n-hBptylidenB)-1-aminohydantoin is 14 grams of MP 150°C (with decomposition). This may be recrystal-lized from dimethylformamide. 

The detailed decomposition (P-H ehminahon) mechanism of the hydrido(alkoxo) complexes, mer-crs-[lr(H)(OR)Cl(PR 3)3] (R = Me, Et, Pr R = Me, Et H trans to Cl) (56, 58, 60), forming the dihydrides mer-cis-[lr H)2Cl PR )2] (57, 59) along with the corresponding aldehyde or ketone was examined (Scheme 6-8). The hydrido(ethoxo) as well as the hydrido(isopropoxo) complexes 60 could also be prepared by oxidative addition of ethanol and isopropanol to the phosphine complexes 39 [44]. In the initial stage of the P-H elimination, a pre-equiUbrium is assumed in which an unsaturated pentacoordinated product is generated by an alcohol-assisted dissociation of the chloride. From this intermediate the transition state is reached, and the rate-determining step is an irreversible scission of the P-C-H bond. This process has a low... 

Homer and Bauer 23> initiated the thermal free radical decomposition of -toluenesulphonyl azide in isopropanol with diethyl peroxydicar-bonate and formulated the mechanism as follows ... 

Table 2 Results from the decomposition reaction of isopropanol on (MPMol2)b and (MPMol2)b series at 150°C conversion, rate for propene formation (rp) and rate for acetone formation (ra).

Correlations between catalytic activity and a variety of bulk properties of semiconductors have been reported (i) the average band gap of III-V and II-VI semiconductors and activity towards hydrogenation of isopropanol (ii) enthalpy of oxides and their activity towards oxidation of propylene and (iii) number of d-electrons (and crystal field stabilization energy) or 3rf-metal oxides and their activity towards N2O decomposition. The last correlation, due to Dowden (1972), is important since it provides a connection between heterogeneous catalysis and coordination chemistry of transition-metal compounds. A correlation between the catalytic activity of transition-metal sulphides towards hydrodesulphurization of aromatic compounds and the position of the transition metal in the periodic table has been made by Whittingham ... 

In view of the very high reactivity of the aminochromes in solution, paper chromatographic studies with these compounds present a number of difficulties. For instance, the ease with which the aminochromes may interact with the solvent system being used, or with impurities in the paper, must be taken into consideration. One of the solvent systems which has been extensively employed for the paper chromatographic separation of aromatic compounds (i.e. an isopropanol-ammonia-water mixture) is quite unsatisfactory in this case, since, in the experience of the author, total decomposition of the aminochromes in basic solvents invariably occurs very rapidly.64 This is not surprising in view of the known sensitivity of the amino-... 

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