- Email: [email protected]
Precipitated aluminas
100 Precipitated
Aluminas
The perennial interest of the catalvst world in orecioitated aluminas as caialyst supports stretches back over many years. Gibbsite is a naturally occurring alumina hydrate, normally used as a raw material for the aluminium salts which are in turn raw materials for the orecioitation of support aluminas. Gibbsite'enjoyed academic limelight in the 1950's and still arouses some interest today. Its academic history is well documented through the publications of researchers such as de Boer, Trambouze, Stumpf, Papge and, more recently, Roquerol (see J. Rouquerol, F. Rououerol and M. Ganteaume, J. Catal. 2, 222-230 (1979)). Along with many others. thev have attemDted to unravel the structural and textural changes which occur when gibbsite is dehydrated. Not perhaps so well known is the classic industrial pay-off which arose from the early work on gibbsite of Tertian and Pa&e (C. R. Acad. Sci. Fr., 1954, 238; 98). This work had confirmed, rde Boer had appreciated (Proc. K. Ned. Acad. Wet., 1954, E, 170, 434) that the important factor influencino the direction in which structural-changes occurred on dehydration was the rate of removal of water. Thus, if water was rapidly removed, e.g. by rapid heating of micron sized particles of gibbsite or by calcining in vacua, a highly disordered gamnaXy~umina was obtained-which could be re-hydrated to bayerite. If, on the other hand no precautions were taken to remove rapidly the water evolved on heating, then boehmite was produced. Patents to the French company Pechiney (Fr. 1,077,116; Fr. 1,077,163; B.P. 754,008; B.P. 811,437.) illustrate beautifully how the industrial workers capitalised on these findings. In exploring the properties of the disordered gamma alumina, they made two dibcoveries which were to allow them to produce a cheap alumina desiccant and a potential catalyst support. Firstly, they found that, a rugged, shaped product could be obtained on rehydration under consitions of high humidity.1 Secondly, activation of this shaped bayerite produced alumina of high surface area with good
desiccant properties. The processing steps leading to the final product are:- (i) grinding gibbsite to particles smaller than 20 urn; (ii) rapid dehydration e.g. in a fluidised bed; (iii) rehydration, but combining the step with a shaping process e.g. granulation with water to form spheres; (iv) drying I;;;er conditions of hiqh humiditv: final activation: This manufacturing process is a fine example of the neat translation of academic discoveries into an industrial product. Carboxylation of y-Butyrolactones with CO using HF-SbF5 Super Acid N. Yoneda et al (Hokkaido University and Kitami Institute of Technology, Japan; see Chem. Sot. Japan. Chem. Lett., 1981, 767) have found that Y-5utyrolactone and derived molecules (CmHgmO etc.) react with carbon monoxide at -200C to 30°C and atmospheric pressure in an HF-SbF5 super-acid medium containing an excess of SbF5 to give the corresponding dicarboxylic acids in good yields (96100%). (Chem. Sot. Japan, Chem. Lett., 767, 1981). Low-pressure Acid
Synthesis
of Glycollic
A new process developed by Kogyo Gijitsu In (KGI) of Japan allows the synthesis of glycollic acid ester (CH20H.C02R), under very mild conditions, from formaldehyde, carbon monoxide and alcohol (ROH). The key to the synthesis is the catalytic use of copper carbonyl. The working catalyst is formed by mixing cuprous oxide with 97% H2SO4 or liquid BF3 and then absorbing CO to form the Formaldehyde is fed into carbonyl. the system under a CO atmosphere, and the alcohol is then added to obtain quantitative yield of the glycollic ester. The ester is separated by vacuum distillation and may subsequently be hydrogenated to ethylene glycoi. _ The copper-based catalysis is carried out at 200C and atmospheric pressure. This can be compared with DuPont's synthesis of glycollic acid and esters which is catalyzed by H2SO4 at 160°200°C and 200-900 atm.
Aluminas
The perennial interest of the catalvst world in orecioitated aluminas as caialyst supports stretches back over many years. Gibbsite is a naturally occurring alumina hydrate, normally used as a raw material for the aluminium salts which are in turn raw materials for the orecioitation of support aluminas. Gibbsite'enjoyed academic limelight in the 1950's and still arouses some interest today. Its academic history is well documented through the publications of researchers such as de Boer, Trambouze, Stumpf, Papge and, more recently, Roquerol (see J. Rouquerol, F. Rououerol and M. Ganteaume, J. Catal. 2, 222-230 (1979)). Along with many others. thev have attemDted to unravel the structural and textural changes which occur when gibbsite is dehydrated. Not perhaps so well known is the classic industrial pay-off which arose from the early work on gibbsite of Tertian and Pa&e (C. R. Acad. Sci. Fr., 1954, 238; 98). This work had confirmed, rde Boer had appreciated (Proc. K. Ned. Acad. Wet., 1954, E, 170, 434) that the important factor influencino the direction in which structural-changes occurred on dehydration was the rate of removal of water. Thus, if water was rapidly removed, e.g. by rapid heating of micron sized particles of gibbsite or by calcining in vacua, a highly disordered gamnaXy~umina was obtained-which could be re-hydrated to bayerite. If, on the other hand no precautions were taken to remove rapidly the water evolved on heating, then boehmite was produced. Patents to the French company Pechiney (Fr. 1,077,116; Fr. 1,077,163; B.P. 754,008; B.P. 811,437.) illustrate beautifully how the industrial workers capitalised on these findings. In exploring the properties of the disordered gamma alumina, they made two dibcoveries which were to allow them to produce a cheap alumina desiccant and a potential catalyst support. Firstly, they found that, a rugged, shaped product could be obtained on rehydration under consitions of high humidity.1 Secondly, activation of this shaped bayerite produced alumina of high surface area with good
desiccant properties. The processing steps leading to the final product are:- (i) grinding gibbsite to particles smaller than 20 urn; (ii) rapid dehydration e.g. in a fluidised bed; (iii) rehydration, but combining the step with a shaping process e.g. granulation with water to form spheres; (iv) drying I;;;er conditions of hiqh humiditv: final activation: This manufacturing process is a fine example of the neat translation of academic discoveries into an industrial product. Carboxylation of y-Butyrolactones with CO using HF-SbF5 Super Acid N. Yoneda et al (Hokkaido University and Kitami Institute of Technology, Japan; see Chem. Sot. Japan. Chem. Lett., 1981, 767) have found that Y-5utyrolactone and derived molecules (CmHgmO etc.) react with carbon monoxide at -200C to 30°C and atmospheric pressure in an HF-SbF5 super-acid medium containing an excess of SbF5 to give the corresponding dicarboxylic acids in good yields (96100%). (Chem. Sot. Japan, Chem. Lett., 767, 1981). Low-pressure Acid
Synthesis
of Glycollic
A new process developed by Kogyo Gijitsu In (KGI) of Japan allows the synthesis of glycollic acid ester (CH20H.C02R), under very mild conditions, from formaldehyde, carbon monoxide and alcohol (ROH). The key to the synthesis is the catalytic use of copper carbonyl. The working catalyst is formed by mixing cuprous oxide with 97% H2SO4 or liquid BF3 and then absorbing CO to form the Formaldehyde is fed into carbonyl. the system under a CO atmosphere, and the alcohol is then added to obtain quantitative yield of the glycollic ester. The ester is separated by vacuum distillation and may subsequently be hydrogenated to ethylene glycoi. _ The copper-based catalysis is carried out at 200C and atmospheric pressure. This can be compared with DuPont's synthesis of glycollic acid and esters which is catalyzed by H2SO4 at 160°200°C and 200-900 atm.