- Email: [email protected]
Sulphuric acid catalysts
80 will be held in Paris from July 16th Zlst. Those who are interested in attending any of these meetings should contact the organiser of that particularl event. CO Hydrogenation
on Rhodium
A recent doctoral thesis with the title "The Mechanism of CO hvdrooenation on Promoted Rhodium Catalysts", by F.G.A. van den Berg, describes results obtained by the author during the period 1979-83 at the Royal Dutch Shell Laboratories in Amsterdam. The work was done under the direction of Professor W.M.H. Sachtler, now at Northwestern University, Evanston, Illinois, and Professor! V. Ponec, University of Leiden, The Netherlands, to which institution the thesis was succesfully submitted. Rhodium catalysts are capable of converting synthesis gas into important chemicals such as ethanol and acetic acid. From an economic point of view, the process is not yet attractive, due 1arqel.v to its lowrelectivitv. The present types of catalysts, drscussed in some detail in the first chapter of the thesis, produce a mixture of ethanol, acetaldehyde and acetic acid ("C -oxygenates"), plus a series of les P. interesting compounds, instead of a single product. Related reactions include the Monsanto process (acetic acid from methanol) and glycol synthesis, as well as the Fischer-Tropsch reaction, and these also receive attention in the first chapter. Model reactions were carried out using manganese and magnesium promoted rhodium (on silica) catalysts. It was foundthatsecondaryreactio~splayanimportant role in determining selectivity; part of the ethanol was formed by hydrogenation.of acetaldehyde and acetic acid. Addition of sodium to the catalysts suppressed the fo~ation of all products except methanol. This observation was explained by assuming that the catalyst contains two types of active sites and this lead to the hypothesis that f$oxygenates are formed via a dual-site mechanism: CO dissociation occurs on rhodium metal and this is followed by hydrogenation to CH on the same sites and migration o 3 the CH3 groups to rhodium ions where they add to CO molecules to form the oxygen-containing products.
mum
- Volume 10 No. 1 - April 1984
A detailed analysis of.the reaction products led to the suggestion that a chain-growth mechanism, similar to that in the Fischer-Tropsch process, occurs in this reaction. The selectivity of Rh towards C2-oxygenates is caused by the exceptional CO-insertion activity of this element. These ideas are confirmed in the thesis by application of highpressure, high-temperature Fourier-transform infrared spectroscopy; the surface was found to be covered by hydrocarbon chains under reaction conditions and the behaviour of these chains was similar to that observed on Fischer-Tropsch catalysts. The mechanism is analysed in some detail and it is concluded that 100% selectivity to ethanol cannot be achieved. A limited number of copies of the thesis are available for distribution and can be obtained by writing to the author at HCP Department, Royal Dutch Shell Laboratories, Badhuisweg 3, 1031 CM Amsterdam. Reduction of Carbon Pore-Mouths
Deposition
at Zeolite
Stamicarbon BV have applied for a patent (Eur. Pat. Application EP86.543(1983)) to cover a method in which a porous catalyst such as ZSM-5 is first treated with an organic molecule such as toluene to fill its pores, the solid is then treated with 0.2 M NaCl to modify the outer surfaces and the material is finally dried athigher temperatures to remove the toluene from the pores. The surface treatment prevents, or at least retards, coke deposition at pore mouths. (See Catalytica Highlights, 9(1983) No. 4).
New Catalytica
Reports
Catalytica Associates plan to produce .the following reports in 1984: "New Directions in Zeolite Technologies", "Metal-Support Interactions: Implications for New Catalyst Technologies~, "State-ofthe-art Techniques for Catalyst Characte,risation" and "Impact of Future Catalytic Developments in the Chemical Industry". Further details can be obtained from Dr. Thaddeus E. Hhite Jr., Catalytica Associates Inc., 430 Ferguson Drive, Bldg. 3, Mountain View, California 94043, USA.
Sulphuric There
Acid Catalysts is a gradual
change
in the
81 design of sulphuric acid plants, to make them more energy efficient and to increase capacity. Factors contributing to these changes and the world picture concerning sulphuric acid manufacture and use were considered in some detail in an article in Chemical b!eek, published in 1982 (Feb.10, p.40). The acid-plant techology market is now dominated by Monsanto and Lurgi but a number of other firms, such as Chemetics International (Toronto), are trying to find a footing. Modern plants, including turbo-generators for electricity production, can recoup their costs from sales of electricity over some five years. Another contributing factor to the improved efficiency is the use of new low pressure-drop catalysts such as those introduced by Haldor Topsde and Monsanto. These are claimed to reduce the pressure drop by 30-60%, giving substantial savings in the cost of operating the main compressor. In addition the catalyst designs hold more dirt.
Technical literature from Monsanto describes in some detail its LP-120 and LP-110 catalysts, supported V 0 materf guraials based on Raschig-ring co 65 tions (f inch and 3/8 inch respectively). LP-120 is intended for use in the first two "catalyst passes", where the temoerature can rise from Q400°C, at the i~nlet, to 2a10°C at the outlet while LP-110 is intended for use in the third and fourth passes, where the temperature rise is less. Because of their configuration, dirt present in the SO from the sulphur burners can oass P urther into the bed and so cataiyst screening is needed less freauentlv. The activities of the catalysts, 'as well as their long-term stabilities, are similar to previous Monsanto products.. Hence the company has encouraged produosrsto make replacements of only half of the catalyst bed in some cases, thereby giving increased efficiencies without the costs of complete catalyst replacements.
CALENDAROFFORTHCOMINGEVENTS 1984 May 7-9, Richmond, USA
VA,
Tenth Conference Organic Reaction ysis Society
(For other spring meetings
of US Catal-
of the Catalysis
Contact: R.L. Augustine, Dept. of Chem., Seton Hall University, South Orange, N.J. 07079 USA Society
to be held in May, see Vo1.9,No2.
May 23-24, Vienna, Austria
Katalystics 5th Annual Fluid Cracking Symposium
Contact: Katalistics B.V., Johannes Vermeerstraat 23, 1071 DK Amsterdam, The Netherlands
June 4-5, Amseterdam, The Netherlands
1984 World Conference on Thermal Analysis
Contact: Dr. V.M. Bhatnagar, Alena Enterprises of Canada, P.O. Box 177S Cornwall, Ontario K6H 5V7, Canada
June 10-13, Pittsburg, USA
ACS 58th Colloid and Surface Science Symposium
Contact: Prof. G.D. Parfitt, Chem.Eng. Dept., Carnegie-Mellon University, Pittsburgh, PA 15213, USA
June 13-15, Moscow, Idaho, USA
Thirty-ninth Northwest Regional ACS Meeting
Contact: R.D. Poshuta, Dept. of Chemistry, Washington State University, Pullman, WA 99164, USA
June 28-29, Uxbridge, UK
Adsorption and Catalysis on Oxide Surfaces
Contact: Prof. G.C. Bond, Brunel University, Dept. of Chemistry, Uxbridge, Middlesex UB8 3PH, UK
July l-6, Edinburgh, Scotland
The Chemistry Group Metals
Contact: Dr. T.A. Stephenson, Dept. of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 355, Scotland
mm,-
Volume 10 No. 1 -April
of Platinum
1984
on Rhodium
A recent doctoral thesis with the title "The Mechanism of CO hvdrooenation on Promoted Rhodium Catalysts", by F.G.A. van den Berg, describes results obtained by the author during the period 1979-83 at the Royal Dutch Shell Laboratories in Amsterdam. The work was done under the direction of Professor W.M.H. Sachtler, now at Northwestern University, Evanston, Illinois, and Professor! V. Ponec, University of Leiden, The Netherlands, to which institution the thesis was succesfully submitted. Rhodium catalysts are capable of converting synthesis gas into important chemicals such as ethanol and acetic acid. From an economic point of view, the process is not yet attractive, due 1arqel.v to its lowrelectivitv. The present types of catalysts, drscussed in some detail in the first chapter of the thesis, produce a mixture of ethanol, acetaldehyde and acetic acid ("C -oxygenates"), plus a series of les P. interesting compounds, instead of a single product. Related reactions include the Monsanto process (acetic acid from methanol) and glycol synthesis, as well as the Fischer-Tropsch reaction, and these also receive attention in the first chapter. Model reactions were carried out using manganese and magnesium promoted rhodium (on silica) catalysts. It was foundthatsecondaryreactio~splayanimportant role in determining selectivity; part of the ethanol was formed by hydrogenation.of acetaldehyde and acetic acid. Addition of sodium to the catalysts suppressed the fo~ation of all products except methanol. This observation was explained by assuming that the catalyst contains two types of active sites and this lead to the hypothesis that f$oxygenates are formed via a dual-site mechanism: CO dissociation occurs on rhodium metal and this is followed by hydrogenation to CH on the same sites and migration o 3 the CH3 groups to rhodium ions where they add to CO molecules to form the oxygen-containing products.
mum
- Volume 10 No. 1 - April 1984
A detailed analysis of.the reaction products led to the suggestion that a chain-growth mechanism, similar to that in the Fischer-Tropsch process, occurs in this reaction. The selectivity of Rh towards C2-oxygenates is caused by the exceptional CO-insertion activity of this element. These ideas are confirmed in the thesis by application of highpressure, high-temperature Fourier-transform infrared spectroscopy; the surface was found to be covered by hydrocarbon chains under reaction conditions and the behaviour of these chains was similar to that observed on Fischer-Tropsch catalysts. The mechanism is analysed in some detail and it is concluded that 100% selectivity to ethanol cannot be achieved. A limited number of copies of the thesis are available for distribution and can be obtained by writing to the author at HCP Department, Royal Dutch Shell Laboratories, Badhuisweg 3, 1031 CM Amsterdam. Reduction of Carbon Pore-Mouths
Deposition
at Zeolite
Stamicarbon BV have applied for a patent (Eur. Pat. Application EP86.543(1983)) to cover a method in which a porous catalyst such as ZSM-5 is first treated with an organic molecule such as toluene to fill its pores, the solid is then treated with 0.2 M NaCl to modify the outer surfaces and the material is finally dried athigher temperatures to remove the toluene from the pores. The surface treatment prevents, or at least retards, coke deposition at pore mouths. (See Catalytica Highlights, 9(1983) No. 4).
New Catalytica
Reports
Catalytica Associates plan to produce .the following reports in 1984: "New Directions in Zeolite Technologies", "Metal-Support Interactions: Implications for New Catalyst Technologies~, "State-ofthe-art Techniques for Catalyst Characte,risation" and "Impact of Future Catalytic Developments in the Chemical Industry". Further details can be obtained from Dr. Thaddeus E. Hhite Jr., Catalytica Associates Inc., 430 Ferguson Drive, Bldg. 3, Mountain View, California 94043, USA.
Sulphuric There
Acid Catalysts is a gradual
change
in the
81 design of sulphuric acid plants, to make them more energy efficient and to increase capacity. Factors contributing to these changes and the world picture concerning sulphuric acid manufacture and use were considered in some detail in an article in Chemical b!eek, published in 1982 (Feb.10, p.40). The acid-plant techology market is now dominated by Monsanto and Lurgi but a number of other firms, such as Chemetics International (Toronto), are trying to find a footing. Modern plants, including turbo-generators for electricity production, can recoup their costs from sales of electricity over some five years. Another contributing factor to the improved efficiency is the use of new low pressure-drop catalysts such as those introduced by Haldor Topsde and Monsanto. These are claimed to reduce the pressure drop by 30-60%, giving substantial savings in the cost of operating the main compressor. In addition the catalyst designs hold more dirt.
Technical literature from Monsanto describes in some detail its LP-120 and LP-110 catalysts, supported V 0 materf guraials based on Raschig-ring co 65 tions (f inch and 3/8 inch respectively). LP-120 is intended for use in the first two "catalyst passes", where the temoerature can rise from Q400°C, at the i~nlet, to 2a10°C at the outlet while LP-110 is intended for use in the third and fourth passes, where the temperature rise is less. Because of their configuration, dirt present in the SO from the sulphur burners can oass P urther into the bed and so cataiyst screening is needed less freauentlv. The activities of the catalysts, 'as well as their long-term stabilities, are similar to previous Monsanto products.. Hence the company has encouraged produosrsto make replacements of only half of the catalyst bed in some cases, thereby giving increased efficiencies without the costs of complete catalyst replacements.
CALENDAROFFORTHCOMINGEVENTS 1984 May 7-9, Richmond, USA
VA,
Tenth Conference Organic Reaction ysis Society
(For other spring meetings
of US Catal-
of the Catalysis
Contact: R.L. Augustine, Dept. of Chem., Seton Hall University, South Orange, N.J. 07079 USA Society
to be held in May, see Vo1.9,No2.
May 23-24, Vienna, Austria
Katalystics 5th Annual Fluid Cracking Symposium
Contact: Katalistics B.V., Johannes Vermeerstraat 23, 1071 DK Amsterdam, The Netherlands
June 4-5, Amseterdam, The Netherlands
1984 World Conference on Thermal Analysis
Contact: Dr. V.M. Bhatnagar, Alena Enterprises of Canada, P.O. Box 177S Cornwall, Ontario K6H 5V7, Canada
June 10-13, Pittsburg, USA
ACS 58th Colloid and Surface Science Symposium
Contact: Prof. G.D. Parfitt, Chem.Eng. Dept., Carnegie-Mellon University, Pittsburgh, PA 15213, USA
June 13-15, Moscow, Idaho, USA
Thirty-ninth Northwest Regional ACS Meeting
Contact: R.D. Poshuta, Dept. of Chemistry, Washington State University, Pullman, WA 99164, USA
June 28-29, Uxbridge, UK
Adsorption and Catalysis on Oxide Surfaces
Contact: Prof. G.C. Bond, Brunel University, Dept. of Chemistry, Uxbridge, Middlesex UB8 3PH, UK
July l-6, Edinburgh, Scotland
The Chemistry Group Metals
Contact: Dr. T.A. Stephenson, Dept. of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 355, Scotland
mm,-
Volume 10 No. 1 -April
of Platinum
1984