CA1138894A - Process for preparing carboxylic acid nitriles - Google Patents
Process for preparing carboxylic acid nitrilesInfo
- Publication number
- CA1138894A CA1138894A CA000375736A CA375736A CA1138894A CA 1138894 A CA1138894 A CA 1138894A CA 000375736 A CA000375736 A CA 000375736A CA 375736 A CA375736 A CA 375736A CA 1138894 A CA1138894 A CA 1138894A
- Authority
- CA
- Canada
- Prior art keywords
- catalyst
- process according
- aldehyde
- alcohol
- hydrogen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C255/00—Carboxylic acid nitriles
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT OF DISCLOSURE
There is disclosed an improvement in the process for the preparation of nitriles by the reaction of alcohols or aldehydes with ammonia in the presence of a supported copper catalyst. The improvement consists in carry-ing out the reaction in the presence of approximately 20 to 50% by volume of hydrogen, based upon the ammonia-hydrogen mixture.
There is disclosed an improvement in the process for the preparation of nitriles by the reaction of alcohols or aldehydes with ammonia in the presence of a supported copper catalyst. The improvement consists in carry-ing out the reaction in the presence of approximately 20 to 50% by volume of hydrogen, based upon the ammonia-hydrogen mixture.
Description
~L~3~4 This invention is directed to an improved process Eor the preparation of nitriles by catalytic conversion of alcohols or aldehydes with ammonia. More specifically, it has been foulld that the addition of hydrogen to the ammonia substantially prolongs the catalyst life and increases the product yield~
Various methods are presently known for producing carboxylic acid nitriles. For example, ammonium salts of carboxylic acids can be dehydrated to form the corresponding nitriles. Also, mixtures of carboxylic acids with ammonia can be converted to the nitriles by splitting off water. These reactions are carried out in the presence oE a dehydration catalyst such as silica gel or A1203 at a temperature of 360 to 500 C.
~A.C. Cope, R.J. Cotter, and L.L. Esters, Org. Syntheses 34, 4 ~1954) ).
These methods have the disadvantage of requiring relativcly high reaction temperaturcs, with attendant high and uneconomic energy requirelnents. This is also true for the corresponding catalytic dehydration of amides, which is carried out, for exampleJ in conjunction with A1203 (D. Boehmer and F. Andrews, J. Amer. Soc. 38, 2504 ~1916) ).
It is also possible to convert acid amides to their corresponding nitriles by non-catalytic means. This is usually done using dehydration agents such as aluminum chloride, phosphorus pentoxide, phosphorus chloride or thionyl chloride. This method can be used for most nitriles, but is economical only in a few cases.
It has been found advantageous to use aldehydes or alcohols as starting material for the preparation oE nitriles. These substances are often available as a result of large scale industrial processes, such as the oxo syntheses.
For example, it is well known that i-butyronitrile can be ~3!51~
prepared by reacting i-butyraldehyde wlth ammonia over a ThO2 catalyst (F. Mailhe, Compt. Rend. 166, 216, (1918)) or a silver catalyst (United States Patent 2,337,421) or a copper catalyst (United States Patent
Various methods are presently known for producing carboxylic acid nitriles. For example, ammonium salts of carboxylic acids can be dehydrated to form the corresponding nitriles. Also, mixtures of carboxylic acids with ammonia can be converted to the nitriles by splitting off water. These reactions are carried out in the presence oE a dehydration catalyst such as silica gel or A1203 at a temperature of 360 to 500 C.
~A.C. Cope, R.J. Cotter, and L.L. Esters, Org. Syntheses 34, 4 ~1954) ).
These methods have the disadvantage of requiring relativcly high reaction temperaturcs, with attendant high and uneconomic energy requirelnents. This is also true for the corresponding catalytic dehydration of amides, which is carried out, for exampleJ in conjunction with A1203 (D. Boehmer and F. Andrews, J. Amer. Soc. 38, 2504 ~1916) ).
It is also possible to convert acid amides to their corresponding nitriles by non-catalytic means. This is usually done using dehydration agents such as aluminum chloride, phosphorus pentoxide, phosphorus chloride or thionyl chloride. This method can be used for most nitriles, but is economical only in a few cases.
It has been found advantageous to use aldehydes or alcohols as starting material for the preparation oE nitriles. These substances are often available as a result of large scale industrial processes, such as the oxo syntheses.
For example, it is well known that i-butyronitrile can be ~3!51~
prepared by reacting i-butyraldehyde wlth ammonia over a ThO2 catalyst (F. Mailhe, Compt. Rend. 166, 216, (1918)) or a silver catalyst (United States Patent 2,337,421) or a copper catalyst (United States Patent
2,337,~22) on dehydrating carrier material.
In addition, other alcohols, such as propanol and n-butanol, are also converted in an analogous manner to their nitriles by reaction with ammonia over molybdenum (VI) oxide/A1203 (United States Patent 2,~187,299) or over nickel/A120~ (C.A. 52, 19~25 (1958)).
The foregoing conversions suffer from a decrease in catalyst activity coupled with the formation of undesirable by-products after a relatively short operating time. Some short-~erm improvement in catalyst behavior can be obtained by such conventional measures as raising the temperature, altering the residence tlme, and changing the catnlyst load.
In most cases, however, the catalyst is rapidly deactivated.
It is, therefore, among the objects of the presen~ invention to provide a process which will enable the conversion of alcohols or aldehydes to nitriles in ~he presence oE such of catalysts, without the aforementioned disadvantages.
It is also among the objects of this invention to provide a process for the catalytic preparation of nitriles which will permit extended catalyst life and improved selectivity.
The present invention is an improvement on the process for preparation of a nitrile from an alcohol or aldehyde with ammonia in the presence of a supported copper catalyst. The improvement comprises carrying out the reaction in the presence of from 20 to 50% by volume of hydrogen, based upon the ammonia/hydrogen mixture. This modification dramatically improves the long term behavior of the copper catalysts belng used. This is particularly suprising and unexpected since hydrogen is liberated in the conversion of both alcohols and aldehydes with ammonia at tlle reaction temperatures ~270 to 320C). 'I`hus, a decrease in the conversion or selectivity would be expected when hydrogen was added. In fact, however, the presence o-E hydrogen as aforesaid not only improves the selectivity of the catalyst in favor of nitrile formation, but also substantially prolongs the life thereof, while maintaining a high conversion rate.
More specifically, in the prior art processes, it is necessary to regenerate the catalyst within three to four weeks at most; whereas when using the present procedure, no decrease in catalyst performance is noticeable, even after three months' continuous operation.
Moreover, the addition of hyclrogen improves the alcohol or aldehyde conversion to nitrile, 'I`he prior art metllocls are capable of producing at most 90 to 95% yield "~llile the process oE tile present invention is capable oE a conversion rate of 99.0 to 99.5%. In addition to the foregoing, the present invention permits raising of the specific velocity ~or throughput) from the prior art value of 0.2 V/Vh to 0.28 V/Vh. This constitutes a 40% increase in throughput.
Thus~ the present invention permits the preparation of nitriles from their corresponding alcohols or aldehydes while achieving dramatic improve-ments in economy and long term catalyst behavior.
In carrying out the present process, the hydrogen is passed over the catalyst together with the ammonia and the alcohol or aldehyde. As previously stated, the hydrogen constitutes from 20 to 50% by volume of the ammonia and hydrogen together. In a preferred form of the invention, the hydrogen is from 25 to 35% by volwne.
~seful starting materials are preferably aliphatic alcohols or alde-hydes, especially -those having 3 -to 8 carbon atoms. Of particular value are normal and isopropanol, 2-ethylbutanol, 2-ethyl-3-methylpen-tanol, 2-ethyl-hexanol and, in particular, normal and/or isobutanol. Of course, the corresponding aldehydes may also be used with equally satisfactory results.
It has bsen found advantageous to react the alcohol or aldehyde with ammonia in a molar ratio of from 0.1:1 to 0.5:1. Copper on a suitable carrier material serves as the catalyst. The preferred catalysts contain from 10 to 80% by weight of copper based upon the total reduced catalyst. Useful carrier materials include silicon dioxide (as silica gel or kieselguhr), aluminum oxide, magnesium oxide, aluminum silicates, and mixtures of aluminum oxide and silicon dioxide. Of these, the silicon dioxide based carriers are most preferable.
The space velocity, based on liquid alcohol or aldehyde, is advantag-eously 0.1 to 0.3 V/Vcath-[t is believed that the beneEicial inEluence of hydrogen in the present conversion can be attributed to prevention or delaying of the form-ation of activity-reducing deposits on the catalyst surface. Thus, the activity and selectivity of the catalyst are maintained over a dramatically longer period at an average higher level than in the case of the prior art methods. When the present process is being used, regeneration of the catalyst need be carried out only after comparatively long periods of operation and, in particularly favorable cases, such regeneration can be omitted entirely.
In carrying out the present method, it is merely necessary, when starting up the plant, to add the required amount of hydrogen to the system.
The hydrogen formed in the synthesis can be recycled by the gas circulation.
Thus, continuous operation requires only that the hydrogen concentration in the circulating gas be maintained at 20 to 50% by volume, based on the total of
In addition, other alcohols, such as propanol and n-butanol, are also converted in an analogous manner to their nitriles by reaction with ammonia over molybdenum (VI) oxide/A1203 (United States Patent 2,~187,299) or over nickel/A120~ (C.A. 52, 19~25 (1958)).
The foregoing conversions suffer from a decrease in catalyst activity coupled with the formation of undesirable by-products after a relatively short operating time. Some short-~erm improvement in catalyst behavior can be obtained by such conventional measures as raising the temperature, altering the residence tlme, and changing the catnlyst load.
In most cases, however, the catalyst is rapidly deactivated.
It is, therefore, among the objects of the presen~ invention to provide a process which will enable the conversion of alcohols or aldehydes to nitriles in ~he presence oE such of catalysts, without the aforementioned disadvantages.
It is also among the objects of this invention to provide a process for the catalytic preparation of nitriles which will permit extended catalyst life and improved selectivity.
The present invention is an improvement on the process for preparation of a nitrile from an alcohol or aldehyde with ammonia in the presence of a supported copper catalyst. The improvement comprises carrying out the reaction in the presence of from 20 to 50% by volume of hydrogen, based upon the ammonia/hydrogen mixture. This modification dramatically improves the long term behavior of the copper catalysts belng used. This is particularly suprising and unexpected since hydrogen is liberated in the conversion of both alcohols and aldehydes with ammonia at tlle reaction temperatures ~270 to 320C). 'I`hus, a decrease in the conversion or selectivity would be expected when hydrogen was added. In fact, however, the presence o-E hydrogen as aforesaid not only improves the selectivity of the catalyst in favor of nitrile formation, but also substantially prolongs the life thereof, while maintaining a high conversion rate.
More specifically, in the prior art processes, it is necessary to regenerate the catalyst within three to four weeks at most; whereas when using the present procedure, no decrease in catalyst performance is noticeable, even after three months' continuous operation.
Moreover, the addition of hyclrogen improves the alcohol or aldehyde conversion to nitrile, 'I`he prior art metllocls are capable of producing at most 90 to 95% yield "~llile the process oE tile present invention is capable oE a conversion rate of 99.0 to 99.5%. In addition to the foregoing, the present invention permits raising of the specific velocity ~or throughput) from the prior art value of 0.2 V/Vh to 0.28 V/Vh. This constitutes a 40% increase in throughput.
Thus~ the present invention permits the preparation of nitriles from their corresponding alcohols or aldehydes while achieving dramatic improve-ments in economy and long term catalyst behavior.
In carrying out the present process, the hydrogen is passed over the catalyst together with the ammonia and the alcohol or aldehyde. As previously stated, the hydrogen constitutes from 20 to 50% by volume of the ammonia and hydrogen together. In a preferred form of the invention, the hydrogen is from 25 to 35% by volwne.
~seful starting materials are preferably aliphatic alcohols or alde-hydes, especially -those having 3 -to 8 carbon atoms. Of particular value are normal and isopropanol, 2-ethylbutanol, 2-ethyl-3-methylpen-tanol, 2-ethyl-hexanol and, in particular, normal and/or isobutanol. Of course, the corresponding aldehydes may also be used with equally satisfactory results.
It has bsen found advantageous to react the alcohol or aldehyde with ammonia in a molar ratio of from 0.1:1 to 0.5:1. Copper on a suitable carrier material serves as the catalyst. The preferred catalysts contain from 10 to 80% by weight of copper based upon the total reduced catalyst. Useful carrier materials include silicon dioxide (as silica gel or kieselguhr), aluminum oxide, magnesium oxide, aluminum silicates, and mixtures of aluminum oxide and silicon dioxide. Of these, the silicon dioxide based carriers are most preferable.
The space velocity, based on liquid alcohol or aldehyde, is advantag-eously 0.1 to 0.3 V/Vcath-[t is believed that the beneEicial inEluence of hydrogen in the present conversion can be attributed to prevention or delaying of the form-ation of activity-reducing deposits on the catalyst surface. Thus, the activity and selectivity of the catalyst are maintained over a dramatically longer period at an average higher level than in the case of the prior art methods. When the present process is being used, regeneration of the catalyst need be carried out only after comparatively long periods of operation and, in particularly favorable cases, such regeneration can be omitted entirely.
In carrying out the present method, it is merely necessary, when starting up the plant, to add the required amount of hydrogen to the system.
The hydrogen formed in the synthesis can be recycled by the gas circulation.
Thus, continuous operation requires only that the hydrogen concentration in the circulating gas be maintained at 20 to 50% by volume, based on the total of
3~:13~
hydrogen and ammonia present in the circulating gas.
Should a reduction in catalyst activity occur, as in -the case of especially long operating times, -the catalyst can be regenerated in situ in the known manner by a step-wise treatment with air/nitrogen mixtures at a temper-ature of 160 to 320C, while gradually raising the oxygen content from 1% to 20%~ The subsequent reduction step is preferably carried out with a hydrogen/
nitrogen mixture ~3% by volume hydrogen) in the same temperature range of 160 to 320C. The space velocity is 1,000 V /V t h The following Examples are illustrative of the invention:
xample 1 Approximately 40 ml/h of i-butanol (0.27 V/Vh), together with 40 Nllh o:f NH3 and 18 Nl/h of H2 are passed over 150 ml of a reduced copper catalyst. The temperature is maintained at 290C and the catalyst contains approximately 50% copper supported on silicon dioxide. The reaction takes place in a quartz tube having an internal diameter of 20 to 22 mm and located in an electrically heated aluminum block furnace. The reaction product is separated into an org~m ic phase and an aqueous phase. The former contains 88 to 90% i-butyronitrile, 5 to 6~ i-butylamine, 1.5 to 2% di-i-butylamine, 1 to 2% of Schiff base, and 0.5 to 0.7% of unreacted i-butanol. The aqueous phase, which amounts to about 25% of the total reaction product, contains about 5 to 6% of i-butyronitrile, about 22% by weight of ammonia, and 2 to 3%
of unidentified components. The long term behavior of the catalyst is summarized in Table 1.
~ ~ dOu~
~ ~ o ~ o o o o - --~o `D Lr~Lf~ ~ ~ ~o ~
l ~ o o o o o o o u) ~ o h o u) o o ~ oo o ~ a)~-.,, I~ ~43 S~ ci~ o oo ~ ~ ~7 0 Z ~~ ~ o~
hI -~i, .
O b4 .~ U~ O Ln O O ~ O
O ~ rl . . , . . . .
h 1:) ..~ ~ ,~
~ _ _ _ .
8 ~ ~ ~ ~ o ~ n N ~`I In 11') CH ~ ~ ~
a~ ~---- _ .
Ul h ~ ~ ~ cr~ m cn o oo a~ ~1 ~
O ~ rl ~ .
~1 ~ ~D ~ ~ ~ ~ ~ ~D
a~ ~ o h X o o o o o o o .,~ 5 o--XO .
~ C) O ~ ~h O ~ Il~
o a~~ ~ ~ _ : _ _ _ _ ~1 ~ ~ ~ ~C~ O O
~! Z ~ ~ ~
a~ ~ 'D ~t` ~I~ t` I`
h ~i Nt~ N ~ N N N
~ O O O O O O O
_ _ .
h ~
O h O
o o o o o o o cd ~ h cr, ~ a~ o~ o o ~ a) ~ N N N N~) t~
1~
_ .
b~ O ~0 0 ~ ~ 1~ ~
~O ~ ~` 00 a) ~ l l l l l l l ~ ~d ~1 ~ o) ~1 ~ u~ oo O ~ ~ ~ n~o ~ I`
1~313E~
Comparison Exa ple l 30 to 40 ml/h of i-butanol, together wi*h 25 to 30 Nl/h of Nl13 are passed over a reduced copper catalyst. The temperature is initially 280C, and no hydrogen is added. Dur:ing -the first ten days of operation, the conversion to i-butyronitrile is 90 -to 96%. However, thereafter the degree of conversion decreases. It can be maintained at 85 to 90~ up to the 26th day oE operation by raising the reaction temperature in stages; first to 290C and then to 300C.
After 30 days of operation, the catalyst had deteriorated so substantially that the experiment had to be terminated. In all other respects, Comparison Example 1 followed the procedure of Example 1. As can readily be seen, a considerably shorter active life of the catalyst is obtained in the event that hydrogen is omitted.
[t is known that catalysts of this character, whose activity has deteriorated, can be regenerated with oxygen/nitrogen mixtures under controlled conditions, followed by activation by reduction. This regeneration process will permit the catalyst to regain almost all of the original activity. How-ever, when the catalyst is re-used, the drop in degree of conversion to the nitrile usually takes place more rapidly than in the first operating period.
Thus, even with regeneration of the catalyst, the prior art processes cannot achieve the results of the present process.
Example 2 In order to prepare 2-ethylbutyronitrile, 40 ml of 2-ethylbutanal in the vapor state, together with 45 Nl/h of ammonia plus 15 Nl/h of hydrogen are passed over 150 ml of a pelletized copper catalyst according to Example 1 at a temperature of 280C. The reaction product is separated into aqueous and organic phases. Even after approximately 80 days of continuous operation, the organic phase continues to contain 95 to 98% of 2-ethyl-butyronitrile. The 89~
conversion of the starting material (2-ethylbutanal) is virtually complete, leaving a residue of merely approximately 0.2% by weight. After 80 days operating time, a gradual decrease in the formation of the nitrile occurs, but this can be reversed by increasing the reaction temperature to 290 to 320C.
Comparison Example 2 The process of Example 2 is carried out except that the hydrogen is omitted. It is then found that there is a definite decrease in catalyst activity after only approximtely 26 days. Moreover, although the desired reaction product comprises 95 to 98% of the organic layer at the outset of the reaction, this proportion falls increasingly after the 26 day period of operation. The conversion can be mainta:ined at 85 to 90% for up to about ~5 operating days by raising the temperature to 300 to 320C. Thereafter, the decrease in act:ivity is so substantial that the reaction productl because of its ]ack of purity, can no longer be purifiecl to an economically acceptable level.
Example 3 A mixture of 30 ml/h of 2-ethyl-3-methylpentanol, together with 25 Nl/h ammonia and 7 Nl/h hydrogen are passed over a similar catalyst to that used in Example 1 at 280 to 300C. The organic phase of the product obtained comprises up to 99% of 2-ethyl-3-methylvaleronitrile. No reduction in catalyst activity whatsoever is observed during the 60 day period of operation.
~ ~ _
hydrogen and ammonia present in the circulating gas.
Should a reduction in catalyst activity occur, as in -the case of especially long operating times, -the catalyst can be regenerated in situ in the known manner by a step-wise treatment with air/nitrogen mixtures at a temper-ature of 160 to 320C, while gradually raising the oxygen content from 1% to 20%~ The subsequent reduction step is preferably carried out with a hydrogen/
nitrogen mixture ~3% by volume hydrogen) in the same temperature range of 160 to 320C. The space velocity is 1,000 V /V t h The following Examples are illustrative of the invention:
xample 1 Approximately 40 ml/h of i-butanol (0.27 V/Vh), together with 40 Nllh o:f NH3 and 18 Nl/h of H2 are passed over 150 ml of a reduced copper catalyst. The temperature is maintained at 290C and the catalyst contains approximately 50% copper supported on silicon dioxide. The reaction takes place in a quartz tube having an internal diameter of 20 to 22 mm and located in an electrically heated aluminum block furnace. The reaction product is separated into an org~m ic phase and an aqueous phase. The former contains 88 to 90% i-butyronitrile, 5 to 6~ i-butylamine, 1.5 to 2% di-i-butylamine, 1 to 2% of Schiff base, and 0.5 to 0.7% of unreacted i-butanol. The aqueous phase, which amounts to about 25% of the total reaction product, contains about 5 to 6% of i-butyronitrile, about 22% by weight of ammonia, and 2 to 3%
of unidentified components. The long term behavior of the catalyst is summarized in Table 1.
~ ~ dOu~
~ ~ o ~ o o o o - --~o `D Lr~Lf~ ~ ~ ~o ~
l ~ o o o o o o o u) ~ o h o u) o o ~ oo o ~ a)~-.,, I~ ~43 S~ ci~ o oo ~ ~ ~7 0 Z ~~ ~ o~
hI -~i, .
O b4 .~ U~ O Ln O O ~ O
O ~ rl . . , . . . .
h 1:) ..~ ~ ,~
~ _ _ _ .
8 ~ ~ ~ ~ o ~ n N ~`I In 11') CH ~ ~ ~
a~ ~---- _ .
Ul h ~ ~ ~ cr~ m cn o oo a~ ~1 ~
O ~ rl ~ .
~1 ~ ~D ~ ~ ~ ~ ~ ~D
a~ ~ o h X o o o o o o o .,~ 5 o--XO .
~ C) O ~ ~h O ~ Il~
o a~~ ~ ~ _ : _ _ _ _ ~1 ~ ~ ~ ~C~ O O
~! Z ~ ~ ~
a~ ~ 'D ~t` ~I~ t` I`
h ~i Nt~ N ~ N N N
~ O O O O O O O
_ _ .
h ~
O h O
o o o o o o o cd ~ h cr, ~ a~ o~ o o ~ a) ~ N N N N~) t~
1~
_ .
b~ O ~0 0 ~ ~ 1~ ~
~O ~ ~` 00 a) ~ l l l l l l l ~ ~d ~1 ~ o) ~1 ~ u~ oo O ~ ~ ~ n~o ~ I`
1~313E~
Comparison Exa ple l 30 to 40 ml/h of i-butanol, together wi*h 25 to 30 Nl/h of Nl13 are passed over a reduced copper catalyst. The temperature is initially 280C, and no hydrogen is added. Dur:ing -the first ten days of operation, the conversion to i-butyronitrile is 90 -to 96%. However, thereafter the degree of conversion decreases. It can be maintained at 85 to 90~ up to the 26th day oE operation by raising the reaction temperature in stages; first to 290C and then to 300C.
After 30 days of operation, the catalyst had deteriorated so substantially that the experiment had to be terminated. In all other respects, Comparison Example 1 followed the procedure of Example 1. As can readily be seen, a considerably shorter active life of the catalyst is obtained in the event that hydrogen is omitted.
[t is known that catalysts of this character, whose activity has deteriorated, can be regenerated with oxygen/nitrogen mixtures under controlled conditions, followed by activation by reduction. This regeneration process will permit the catalyst to regain almost all of the original activity. How-ever, when the catalyst is re-used, the drop in degree of conversion to the nitrile usually takes place more rapidly than in the first operating period.
Thus, even with regeneration of the catalyst, the prior art processes cannot achieve the results of the present process.
Example 2 In order to prepare 2-ethylbutyronitrile, 40 ml of 2-ethylbutanal in the vapor state, together with 45 Nl/h of ammonia plus 15 Nl/h of hydrogen are passed over 150 ml of a pelletized copper catalyst according to Example 1 at a temperature of 280C. The reaction product is separated into aqueous and organic phases. Even after approximately 80 days of continuous operation, the organic phase continues to contain 95 to 98% of 2-ethyl-butyronitrile. The 89~
conversion of the starting material (2-ethylbutanal) is virtually complete, leaving a residue of merely approximately 0.2% by weight. After 80 days operating time, a gradual decrease in the formation of the nitrile occurs, but this can be reversed by increasing the reaction temperature to 290 to 320C.
Comparison Example 2 The process of Example 2 is carried out except that the hydrogen is omitted. It is then found that there is a definite decrease in catalyst activity after only approximtely 26 days. Moreover, although the desired reaction product comprises 95 to 98% of the organic layer at the outset of the reaction, this proportion falls increasingly after the 26 day period of operation. The conversion can be mainta:ined at 85 to 90% for up to about ~5 operating days by raising the temperature to 300 to 320C. Thereafter, the decrease in act:ivity is so substantial that the reaction productl because of its ]ack of purity, can no longer be purifiecl to an economically acceptable level.
Example 3 A mixture of 30 ml/h of 2-ethyl-3-methylpentanol, together with 25 Nl/h ammonia and 7 Nl/h hydrogen are passed over a similar catalyst to that used in Example 1 at 280 to 300C. The organic phase of the product obtained comprises up to 99% of 2-ethyl-3-methylvaleronitrile. No reduction in catalyst activity whatsoever is observed during the 60 day period of operation.
~ ~ _
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a process for the preparation of a nitrile by reacting an alcohol or aldehyde with ammonia in the presence of a copper catalyst supported on a carrier, the improvement which comprises carrying out the reaction in the presence of from 20 to 50% by volume of hydrogen, based on the ammonia-hydrogen mixture.
2. The process according to Claim l wherein said alcohol or aldehyde is aliphatic.
3. The process according to Claim 1 or 2, wherein said alcohol or aldehyde has from 3 to 8 carbon atoms.
4. The process according to Claim l wherein said alcohol or aldehyde is n-propanol, i-propanol, 2-ethylbutanol, 2-ethyl-3-methylpentanol, 2-ethylhexanol, n-butanol, i-butanol, n-propanol, i-propanal, 2-ethylbutanal, 2-ethyl-3-methylpentanal, 2-ethylhexanal, n-butanal, or i-butanal.
5. The process according to Claim 1 wherein the alcohol or aldehyde is n-butanol, i-butanol, n-butanal, or i-butanal.
6. The process according to Claim 1 wherein the carrier is formed of SiO2, A12O3, MgO, aluminum silicate, or a mixture of A12O3 and SiO2.
7. The process according to Claim 1 wherein the carrier is formed of SiO2.
8. The process according to Claim 1 wherein the mol ratio of said alcohol or aldehyde to ammonia is from 0.1:1 to 0.5:1.
9. The process according to Claim 1 wherein the catalyst comprises from 10% to 80% copper based on the total reduced catalyst.
10. The process according to Claim 1 wherein the alcohol or aldehyde contacts the catalyst at a space velocity of from 0.1 to 0.3 volume of said alcohol or aldehyde as liquid to 1 volume of said catalyst per hour.
11. The process according to Claim 1 wherein hydrogen is present in an amount of from 25 to 35% by volume, based on the ammonia-hydrogen mixture.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19803014729 DE3014729A1 (en) | 1980-04-17 | 1980-04-17 | IMPROVED METHOD FOR PRODUCING CARBONIC ACID NITRILS |
| DEP3014729.6 | 1980-04-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1138894A true CA1138894A (en) | 1983-01-04 |
Family
ID=6100248
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000375736A Expired CA1138894A (en) | 1980-04-17 | 1981-04-16 | Process for preparing carboxylic acid nitriles |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0038507A1 (en) |
| CA (1) | CA1138894A (en) |
| DE (1) | DE3014729A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4731464A (en) * | 1980-07-30 | 1988-03-15 | American Cyanamid Company | Process for the synthesis of an alkyl nitrile from an alkanol |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19518398A1 (en) * | 1995-05-19 | 1996-11-21 | Sueddeutsche Kalkstickstoff | Process for the production of aromatic nitriles |
| DE19647795A1 (en) * | 1996-11-19 | 1998-05-20 | Sueddeutsche Kalkstickstoff | Production of aromatic nitrile compounds |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2337422A (en) * | 1941-10-07 | 1943-12-21 | Rohm & Haas | Preparation of nitriles from primary alcohols |
| US2365721A (en) * | 1941-10-31 | 1944-12-26 | Sharples Chemicals Inc | Manufacture of aliphatic amines |
| US2795600A (en) * | 1954-06-25 | 1957-06-11 | Union Carbide & Carbon Corp | Production of nitriles |
-
1980
- 1980-04-17 DE DE19803014729 patent/DE3014729A1/en not_active Withdrawn
-
1981
- 1981-04-14 EP EP81102834A patent/EP0038507A1/en not_active Withdrawn
- 1981-04-16 CA CA000375736A patent/CA1138894A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4731464A (en) * | 1980-07-30 | 1988-03-15 | American Cyanamid Company | Process for the synthesis of an alkyl nitrile from an alkanol |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0038507A1 (en) | 1981-10-28 |
| DE3014729A1 (en) | 1981-10-22 |
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