1. From previous research of several cobalt oxide catalysts, Ammonia-treated
cobalt on carbon has high selectivity (>80%) for the linear oligomerization of
1-butene. NaOH-treated catalysts were not nearly as active. However, it was
found that the concentrations of Ammonia (15M) and Sodium Hydroxide
(<2M) solutions used to treat catalysts were not the same.
This study was aimed to identify why the NaOH-treatment gives much lower
catalytic activity when prepared with comparable concentrations (2M for
NH4OH and NaOH). Also, this study was further evaluated by adding washing
step (100ml of DI water) in order to see if pH has effect on the support.
Figure 1. Experimental setup
• Repeatability
=> Co/C without any other modification still shows notable differences in activity
•Different treatment
=> Both NaOH and NH4OH with 2M of concentrations show high activity. Noticeably, NaOH is
more active at some concentration.
•Different number of treatment (NH4OH and NaOH)
=> Double NH4OH treatment has larger effect on both isomerization and oligomerization
activity.
=> Double NaOH treatment has the lowest activity among all treatments. on both
isomerization and oligomerization activity.
•Washing effect
=> Both washed samples are more active for both isomerization and oligomerization
• ‘Possible scenario for washing effect’
0%
5%
10%
15%
20%
25%
30%
0 2 4 6 8 10 12
Oligomeryield
TOS
Effect of treatment on the oligomer yield
Co/C
1x NaOH Co/C
1x NH4OH Co/C
The Modification of the Carbon Support
and its Impact on the Catalytic Activity
Nayeong Kim, Joseph P. Chada, Prof. George Huber
Department of Chemical and Biological Engineering
Introduction Conclusion
• Since the Co/C without any other
modification still shows notable differences in
activity, it is hard to say it is reproducible.
• NaOH treatment results high catalytic
activity which is comparable with NH4OH
treatment. As a result, under same
concentration, both NaOH and NH4OH
treatments give high activity.
•Unlike double treatment of NH4OH which
result greater effect on the activity, double
treatment of NaOH results the lowest catalytic
activity.
•Washing (neutral pH) results increasing both
isomerization and oligomerization activity.
Further Questions
• Why washing impact on the catalytic
activity?
-Does washing decrease cobalt loading?
-Is water interacting with cobalt?
-What are washed off and how does it
increase catalytic activity?
• Does acid containing nitrogen treatment
(eg.HNO3) works as well as NaOH and
NH4OH?
-How various pH actually impact on the
catalytic activity?
References
Data Analysis
In this project, various modification of the carbon support was performed:
• Different treatment solutions (NH4OH vs NaOH) in order to check
whether nitrogen contents has effect on the activity
• Different number of treatment (single vs double treatment)
• Different pH of catalyst (not washed vs washed) in order to check the
effect of pH or –OH on the activity
• Same solution in multiple times in order to check the repeatability
Table 1. Summary of prepared treatment solutions
Performance
[1] Kim, Yong Tae, et al., Low temperature oligomerization
of 1-butene with H-ferrierite, Submitted
[2] Schultz, R., Schuck, J., & Wildi, B. (1966). Olefin
dimerization over cobalt-oxide-on-carbon catalysts: I.
Propylene dimerization. Journal of Catalysis, 6(3), 385-396.
Co/C NaOH NH4OH
Co/C 1xNaOH 1xNH4OH
2xNaOH 2xNH4OH
1xNaOH (W)
2xNaOH (W)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
0 2 4 6 8 10 12
Oligomeryield
TOS
Effect of washing on the oligomer yield
1x NaOH Co/C
1x NaOH W Co/C
2x NaOH Co/C
2x NaOH WCo/C
0%
10%
20%
30%
40%
50%
60%
70%
0 2 4 6 8 10 12
Oligomerselectivity
TOS
Effect of washing on the oligomer selectivity
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
0 2 4 6 8 10 12
1-ButeneConversion
TOS
Effect of washing on the feed conversion
0%
5%
10%
15%
20%
25%
30%
0 2 4 6 8 10 12 14
OligomerYield
TOS (h)
Co/C
Co/C Batch 1
Co/C Batch 2
Co/C Batch 1
0%
10%
20%
30%
40%
50%
60%
70%
0 2 4 6 8 10 12 14
OligomerSelectivity
TOS (h)
Co/C
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
0 2 4 6 8 10 12 14
1-ButeneConversion
TOS (h)
Co/C
-10%
0%
10%
20%
30%
40%
50%
60%
70%
0 2 4 6 8 10 12
Oligomerselectivity
TOS
Effect of treatment on the oligomer selectivity
20%
30%
40%
50%
60%
70%
80%
90%
0 2 4 6 8 10 12
Oligomerselectivity
TOS
Effect of treatment on the feed conversion
0%
10%
20%
30%
40%
50%
60%
70%
0 2 4 6 8 10 12
Oligomerselectivity
TOS
Effect of number of treatment on the oligomer selectivity
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
0 2 4 6 8 10 12
Oligomerselectivity
TOS
Effect of number of treatment on the feed conversion
Na+
OH
|
Carbon
OH
|
Carbon
Wash
OH
|
Carbon
OH
|
Carbon
OH
|
Carbon
Wash
Co Co Na+
Co
Each washing steps might
wash sodium off so that it
has less hindrance and
higher catalytic activities
than one without washing.
Hypothesis
1) The experiments would be repeatable. (Co/C in different batches would
result relatively same oligomer yield, selectivity and conversion. )
2) The double treatment would result better isomerization and
oligomerization activity than single treatment for both NH4OH and NaOH.
3) The catalyst with washing off step would give better isomerization and
oligomerization activity than one without washing.
0%
5%
10%
15%
20%
25%
30%
0 2 4 6 8 10 12
Oligomeryield
TOS
Effect of number of treatment on the oligomer yield
1x NH4OH Co/C
2x NH4OH Co/C
1x NaOH Co/C
2x NaOH Co/C