Diacetone alcohol decomposition and benzaldehyde Cannizzaro reaction as test reactions for the basic strength measurements of alumina, magnesia, Amberlyst type resins (A-15, XN 1010, A-26, A-21), Nafion NR 50 and solid sulfuric acid

Abstract

The decomposition of diacetone alcohol to acetone proceeding at 303 K as well as the Cannizzaro transformation of benzaldehyde at 323 K leading to benzyl alcohol, can be regarded as useful test reactions in investigating the basic properties of solid catalysts. The minimum basic strength H_min needed to initiate the conversion of diacetone alcohol is within the range of 11.8-13.3, and for benzaldehyde transformation the value is 15.4. The above mentioned test reactions were used to study the basic strength of different solid acid-base catalysts. The conclusions can be presented as follows: (a) solid NaOH and Amberlyst type resin A-26 exhibit basic strength of H_ ≥ 15.4 respectively, the basic centers of A-21 resin possess lower strength 11.8-13.3 ≤ H_ < 15.4; (b) Amberlyst-15, Amberlyst XN 1010, Nafion NR 50 resins and solid sulfuric acid (SSA) possess basic strength of H_ < 11.8-13.3; (c) the basic strength of alumina and magnesia is 11.8-13.3 ≤ H_ < 15.4 whether they have been calcined at 753 K or not.

Selectivity Switch in the Aerobic 1,2‐Propandiol Oxidation Catalyzed by Diamine‐Stabilized Palladium Nanoparticles

“…The addition of water shifts the equilibrium of the condensation reaction in favor to free hydroxyacetone ( i. e ., a catalytic reaction carried out with 1 in neat n ‐hexane suppresses the hydrolysis of the acetal (Table 1)), which can further undergo a 1 ‐catalyzed dehydrogenation reaction (Scheme 4, reaction b) giving pyruvaldehyde. The latter compound is known to be a reactive intermediate which undergoes either a base‐mediated Cannizzaro reaction [39] to lactic acid ( i. e . 1 @C K ‐catalyzed aerobic 1,2‐PD (0.274 M) oxidation reaction carried out in the presence of an equimolar amount of NaOH at 140 °C for 18 h, gave lactic acid as main reaction product (lactic acid, 50.4 % vs acetic acid, 41.1 %), or reacts with water to give the corresponding pyruvacetal (Scheme 4, reaction c), which then dehydrogenate to give pyruvic acid (Scheme 4, reaction d).…”

“…The addition of water shifts the equilibrium of the condensation reaction in favor to free hydroxyacetone (i. e., a catalytic reaction carried out with 1 in neat n-hexane suppresses the hydrolysis of the acetal (Table 1)), which can further undergo a 1-catalyzed dehydrogenation reaction (Scheme 4, reaction b) giving pyruvaldehyde. The latter compound is known to be a reactive intermediate which undergoes either a base-mediated Cannizzaro reaction [39] to lactic acid (i. e. 1@C K -catalyzed aerobic 1,2-PD (0.274 M) oxidation reaction carried out in the presence of an equimolar amount of NaOH at 140°C for 18 h, gave lactic acid as main reaction product (lactic acid, 50.4 % vs acetic acid, 41.1 %), or reacts with water to give the corresponding pyruvacetal (Scheme 4, reaction c), which then dehydrogenate to give pyruvic acid (Scheme 4, reaction d). The three alcohol dehydrogenation reactions which converts 1,2-PD into PA (Scheme 4, reactions a, b and d) are catalyzed by surface Pd-OH species of 1@C K (XPS evidence), which are transformed into PdÀ H (i. e., Pd-OH reacts with the alcohol to give the corresponding Pd-alcoholate and water and the former undergoes then a Pd-β-hydride elimination reaction giving PdÀ H along with the release of the corresponding carbonyl or carboxyl species).…”

Acid strength measurements of Amberlyst 15 resin, p-xylene-2-sulfonic acid and chlorosulfonic and sulfuric acid treated SiO2, Al2O3, TiO2 and MgO

“…In our works we used the similar strategy for acid and basic strength measurements [40,41]. It is close to the Hammett indicator method where instead of color change observation, the chemical transformation of protonated or deprotonated molecules is measured.…”