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NPL Working Party on Catalyst Reference Materials
715
PROGRESS REPORT ON THE WORK OF THE SCI/IUPAC/NPL
WORKING PARTYON
CATALYST REFERENCE MATERIALS C.C.
BOND
',
R.L.
MOSS b, R.C.
PITKETHLEY
',
K.S.W.
SING
and R. WILSON
a
Department of I n d u s t r i a l Chemistry, Brunel U n i v e r s i t y , Uxbridge, Middlesex(UK)
b
Warren S p r i n g Laboratory, Stevenage, H e r t f o r d s h i r e (UK)
c
ex BP Research Centre, Sunbury, Middlesex (UK)
d
School of Chemistry, Brunel University, Uxbridge, Middlesex (UK)
e
Division of Chemical Standards, National Physical Laboratory, Teddington, Middlesex (UK)
INTRODUCTION A f t e r t h e s u c c e s s f u l conclusion of t h e Society of Chemical I n d u s t r y (SCI)/IUPAC/ National Physical Laboratory (NPL) p r o j e c t on s u r f a c e a r e a r e f e r e n c e m a t e r i a l s ( r e f . I ) , it w a s suggested by IUPAC Commission I 6 on Colloid and Surface Chemistry t h a t SCI should i n i t i a t e a similar p r o j e c t on c a t a l y s t r e f e r e n c e m a t e r i a l s .
This
was agreed by t h e SCI Colloid and Surface Chemistry Group and a working p a r t y c o n s i s t i n g of t h e a u t h o r s with R o f e s s o r Sing as chairman, Dr. Wilson as s e c r e t a r y and Professor Kemball ( U n i v e r s i t y of Minburgh) r e p r e s e n t i n g IUPAC Commission I 6
was s e t up and t h e f i r s t meeting took place i n January 1976, when i t was decided t h a t t h e p r o j e c t should be based at t h e NPL which already had a g e n e r a l programme
on r e f e r e n c e m a t e r i a l s . The d e c i s i o n t o e s t a b l i s h a s e t of heterogeneous c a t a l y s t r e f e r e n c e m a t e r i a l s
was j u s t i f i e d f o r t h e following reasons:( A ) The v a r i e t y of methods used i n d i f f e r e n t l a b o r a t o r i e s f o r t h e p r e p a r a t i o n o f c a t a l y s t s makes i t d i f f i c u l t t o compare published r e s u l t s . The a v a i l a b i l i t y of c a t a l y s t r e f e r e n c e m a t e r i a l s would g r e a t l y improve t h e s i t u a t i o n and should thereby a i d progress i n r e l a t i n g t h e a c t i v i t y of c a t a l y s t s t o t h e i r composition and s t r u c t u r e .
(B) Readily a v a i l a b l e c a t a l y s t r e f e r e n c e m a t e r i a l s would f a c i l i t a t e t h e v a l i d a t i o n of procedures f o r c a t a l y s t c h a r a c t e r i s a t i o n and performance t e s t i n g and permit t h e comparison of t h e a c t i v i t y and e f f i c i e n c y of o t h e r c a t a l y s t s . ( C ) For t h e t r a i n i n g of research s t u d e n t s and experimental workers. Eight c a t a l y s t s were chosen as being p o t e n t i a l l y s u i t a b l e as r e f e r e n c e m a t e r i a l s .
Three of t h e s e , ( i ) 13$ A 1 0 /Si02 acid-type cracking c a t a l y s t , ( i i )C O / M O / A ~ ~ O ~ 2 3
716 desulphurisation catalyst and (iii) 10% Ni/Si02 hydrogenation catalyst where selected for immediate attention. Others under consideration included (iv) bismuth molybdate, (v) chromium oxide gel, (vi) 0.5% or 0.75% Ft on A1203, (vii)2% Pd on Y-A1203, (viii) 0.5
-
0.75% Pt/Re/Al2O3.
Selection of the catalyst
was based on industrial relevance and commercial availability and in drawing up detailed specifications for catalysts (i), (ii) and (iii), the requirements of chemical engineers in addition to those of chemists were considered.
PROGRESS Approximately 100 kg quantities of catalyst (i), (ii) and (iii) have been donated by Joseph Crosfield and Sons Ltd, Laporte Industries Ltd and Akzo Chemie Nederland bv respectively. Representative, approximately 100 g, samples have been abstracted using a specially constructed 20 litre rotating riffle. Such a sampling procedure was considered essential as it cannot be assumed that the bulk materials are completely homogeneous with respect to their physical and chemical properties; the catalysts are in the form of powders or granules with mean particle sizes of approximately 90
for (i), 1 nun for (ii) and 80 Lrn f o r (iii) and there is a tendency for the finer and coarser material to separate. Questionnaires asking for advice on characterisation and test procedures on
catalysts (i), (ii) and (iii) have been distributed to over sixty experts, mainly in the UK.
About one third of those contacted have offered advice and practical
assistance, and agreed to participate in the physical characterisation and testing of the materials. After careful consideration of this advice, the Working Party is writing characterisation and test programmes. Details of the procedures to be used, including pretreatment Conditions, will be specified and representative samples of the catalysts are being distributed to the participating laboratories. In the case of Ni/Si02, it was necessary to ask a few of the participating laboratories to make a preliminary assessment of the "ease of reduction" before the pretreatment conditions could be speoified. Routine measurements of chemical analysis, surface area and pore size distribution, have been specified for all three catalysts and will be made by a number of the participating laboratories. It was more difficult to specify methods f o r the measurement of catalyst activity. However, after careful consideration, it was agreed that cumene cracking should be specified for (i),
.
thiophene desulphurisation for (ii) and benzene hydrogenation for (iii)
Other methods to be used by some of the participants will include selective chemisorption, electron microscopy, X-ray line broadening, Auger and photoelectron spectroscopy and secondary ion mass spectroscopy. When the Working Party is satisfied that the selected catalysts are suitable
717 f o r use as r e f e r e n c e m a t e r i a l s , d e t a i l e d r e s u l t s w i l l be made a v a i l a b l e as soon
as p o s s i b l e and t h e c e r t i f i e d samples w i l l be made a v a i l a b l e v i a t h e NPL. Further o f f e r s of a c t i v e p a r t i c i p a t i o n would be welcome.
The Working Party
would a l s o be g r a t e f u l f o r a s s i s t a n c e i n o b t a i n i n g bulk q u a n t i t i e s o f p o t e n t i a l c a t a l y s t r e f e r e n c e m a t e r i a l s , p a r t i c u l a r l y supported noble metal c a t a l y s t s .
ACKNOWLEDGMENTS We a r e very g r a t e f u l t o t h e t h r e e companies, Joseph C r o s f i e l d and Sons Ltd, Laporte I n d u s t r i e s Ltd and Akzo Chemie Nederland bv f o r t h e i r k i n d donations of bulk q u a n t i t i e s of c a t a l y s t m a t e r i a l s .
We a r e a l s o indebted t o t h e l a b o r a t o r i e s
t h a t a r e p a r t i c i p a t i n g i n t h e measurement programme.
RFPERENCE 1 D.H. E v e r e t t , G.D. P a r f i t t , K.S.W. 24 (1974) 199-219-
Sing and R. Wilson, J.appl.Chem.
Bioteohnol.
PROGRESS REPORT ON THE WORK OF THE SCI/IUPAC/NPL
WORKING PARTYON
CATALYST REFERENCE MATERIALS C.C.
BOND
',
R.L.
MOSS b, R.C.
PITKETHLEY
',
K.S.W.
SING
and R. WILSON
a
Department of I n d u s t r i a l Chemistry, Brunel U n i v e r s i t y , Uxbridge, Middlesex(UK)
b
Warren S p r i n g Laboratory, Stevenage, H e r t f o r d s h i r e (UK)
c
ex BP Research Centre, Sunbury, Middlesex (UK)
d
School of Chemistry, Brunel University, Uxbridge, Middlesex (UK)
e
Division of Chemical Standards, National Physical Laboratory, Teddington, Middlesex (UK)
INTRODUCTION A f t e r t h e s u c c e s s f u l conclusion of t h e Society of Chemical I n d u s t r y (SCI)/IUPAC/ National Physical Laboratory (NPL) p r o j e c t on s u r f a c e a r e a r e f e r e n c e m a t e r i a l s ( r e f . I ) , it w a s suggested by IUPAC Commission I 6 on Colloid and Surface Chemistry t h a t SCI should i n i t i a t e a similar p r o j e c t on c a t a l y s t r e f e r e n c e m a t e r i a l s .
This
was agreed by t h e SCI Colloid and Surface Chemistry Group and a working p a r t y c o n s i s t i n g of t h e a u t h o r s with R o f e s s o r Sing as chairman, Dr. Wilson as s e c r e t a r y and Professor Kemball ( U n i v e r s i t y of Minburgh) r e p r e s e n t i n g IUPAC Commission I 6
was s e t up and t h e f i r s t meeting took place i n January 1976, when i t was decided t h a t t h e p r o j e c t should be based at t h e NPL which already had a g e n e r a l programme
on r e f e r e n c e m a t e r i a l s . The d e c i s i o n t o e s t a b l i s h a s e t of heterogeneous c a t a l y s t r e f e r e n c e m a t e r i a l s
was j u s t i f i e d f o r t h e following reasons:( A ) The v a r i e t y of methods used i n d i f f e r e n t l a b o r a t o r i e s f o r t h e p r e p a r a t i o n o f c a t a l y s t s makes i t d i f f i c u l t t o compare published r e s u l t s . The a v a i l a b i l i t y of c a t a l y s t r e f e r e n c e m a t e r i a l s would g r e a t l y improve t h e s i t u a t i o n and should thereby a i d progress i n r e l a t i n g t h e a c t i v i t y of c a t a l y s t s t o t h e i r composition and s t r u c t u r e .
(B) Readily a v a i l a b l e c a t a l y s t r e f e r e n c e m a t e r i a l s would f a c i l i t a t e t h e v a l i d a t i o n of procedures f o r c a t a l y s t c h a r a c t e r i s a t i o n and performance t e s t i n g and permit t h e comparison of t h e a c t i v i t y and e f f i c i e n c y of o t h e r c a t a l y s t s . ( C ) For t h e t r a i n i n g of research s t u d e n t s and experimental workers. Eight c a t a l y s t s were chosen as being p o t e n t i a l l y s u i t a b l e as r e f e r e n c e m a t e r i a l s .
Three of t h e s e , ( i ) 13$ A 1 0 /Si02 acid-type cracking c a t a l y s t , ( i i )C O / M O / A ~ ~ O ~ 2 3
716 desulphurisation catalyst and (iii) 10% Ni/Si02 hydrogenation catalyst where selected for immediate attention. Others under consideration included (iv) bismuth molybdate, (v) chromium oxide gel, (vi) 0.5% or 0.75% Ft on A1203, (vii)2% Pd on Y-A1203, (viii) 0.5
-
0.75% Pt/Re/Al2O3.
Selection of the catalyst
was based on industrial relevance and commercial availability and in drawing up detailed specifications for catalysts (i), (ii) and (iii), the requirements of chemical engineers in addition to those of chemists were considered.
PROGRESS Approximately 100 kg quantities of catalyst (i), (ii) and (iii) have been donated by Joseph Crosfield and Sons Ltd, Laporte Industries Ltd and Akzo Chemie Nederland bv respectively. Representative, approximately 100 g, samples have been abstracted using a specially constructed 20 litre rotating riffle. Such a sampling procedure was considered essential as it cannot be assumed that the bulk materials are completely homogeneous with respect to their physical and chemical properties; the catalysts are in the form of powders or granules with mean particle sizes of approximately 90
for (i), 1 nun for (ii) and 80 Lrn f o r (iii) and there is a tendency for the finer and coarser material to separate. Questionnaires asking for advice on characterisation and test procedures on
catalysts (i), (ii) and (iii) have been distributed to over sixty experts, mainly in the UK.
About one third of those contacted have offered advice and practical
assistance, and agreed to participate in the physical characterisation and testing of the materials. After careful consideration of this advice, the Working Party is writing characterisation and test programmes. Details of the procedures to be used, including pretreatment Conditions, will be specified and representative samples of the catalysts are being distributed to the participating laboratories. In the case of Ni/Si02, it was necessary to ask a few of the participating laboratories to make a preliminary assessment of the "ease of reduction" before the pretreatment conditions could be speoified. Routine measurements of chemical analysis, surface area and pore size distribution, have been specified for all three catalysts and will be made by a number of the participating laboratories. It was more difficult to specify methods f o r the measurement of catalyst activity. However, after careful consideration, it was agreed that cumene cracking should be specified for (i),
.
thiophene desulphurisation for (ii) and benzene hydrogenation for (iii)
Other methods to be used by some of the participants will include selective chemisorption, electron microscopy, X-ray line broadening, Auger and photoelectron spectroscopy and secondary ion mass spectroscopy. When the Working Party is satisfied that the selected catalysts are suitable
717 f o r use as r e f e r e n c e m a t e r i a l s , d e t a i l e d r e s u l t s w i l l be made a v a i l a b l e as soon
as p o s s i b l e and t h e c e r t i f i e d samples w i l l be made a v a i l a b l e v i a t h e NPL. Further o f f e r s of a c t i v e p a r t i c i p a t i o n would be welcome.
The Working Party
would a l s o be g r a t e f u l f o r a s s i s t a n c e i n o b t a i n i n g bulk q u a n t i t i e s o f p o t e n t i a l c a t a l y s t r e f e r e n c e m a t e r i a l s , p a r t i c u l a r l y supported noble metal c a t a l y s t s .
ACKNOWLEDGMENTS We a r e very g r a t e f u l t o t h e t h r e e companies, Joseph C r o s f i e l d and Sons Ltd, Laporte I n d u s t r i e s Ltd and Akzo Chemie Nederland bv f o r t h e i r k i n d donations of bulk q u a n t i t i e s of c a t a l y s t m a t e r i a l s .
We a r e a l s o indebted t o t h e l a b o r a t o r i e s
t h a t a r e p a r t i c i p a t i n g i n t h e measurement programme.
RFPERENCE 1 D.H. E v e r e t t , G.D. P a r f i t t , K.S.W. 24 (1974) 199-219-
Sing and R. Wilson, J.appl.Chem.
Bioteohnol.