CA1052818A - Manufacture of amides - Google Patents
Manufacture of amidesInfo
- Publication number
- CA1052818A CA1052818A CA206,346A CA206346A CA1052818A CA 1052818 A CA1052818 A CA 1052818A CA 206346 A CA206346 A CA 206346A CA 1052818 A CA1052818 A CA 1052818A
- Authority
- CA
- Canada
- Prior art keywords
- crude product
- resin
- sodium
- bed
- cation exchange
- 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
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C233/00—Carboxylic acid amides
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Alkali metal catalyst residues are removed from the crude product of N,N-dialkylamide-forming process by contacting tho crude product with a cation exchange resin.
Alkali metal catalyst residues are removed from the crude product of N,N-dialkylamide-forming process by contacting tho crude product with a cation exchange resin.
Description
-```` ~.o5~
THE PRESE~T INVENTION relates to the manufacture of amides, in particular to the manufacture of N,N-dialkylamides.
~ ,~-dialkylamides such as dimethylformamide and dimethylacetamide may be manufactured by reaction of an alkyl ester of the relevant acid with a dialkylamine, e.g.
methyl formate or methyl acetate with dimethylamine. In the case of the formate the reaction is very rapid and no catalyst is required, but the acetate is far slower and for commercial operation requires a catalyst, conventionally an alkali metal alkoxide such as sodium methoxide. An alternative manufacturing process for the ~,~-dialkylamides, especially for dimethylformamide, involves the reaction of the dialkylamine, e.g. dimethylamine with carbon monoxide under pressure and again a catalyst such as an alkali metal alkoxide is used.
Both types of process using an alkali metal alkoxide catalyst yield a crude product which may contain the N,~-dialkyl-amide, alcohol from the alkali metal alkoxide, alkali metal ions, unchanged dialkylamine and, in the case of an ester reactant, unchanged ester. This mixture is usually refined by distillation but the alkali metal ions must be removed first to avoid precipitation of solids in the distillation boiler and to destroy the catalytic effect of the alkoxide.
Conventionally, the alkali metal is removed by acid and/or water washing but this procedure is time consuming and inevitably results in losses of organic material as well as presenting an effluent disposal problem We have now devised an alternative and improved method of catalyst removal.
According to the invention alkali metal catalyst 0 residues are removed from the crude product of an ~ 5~,~8~.8 dialkylamide-forming process by contacting the crude product with a cation exchange resin, The ~,~-dialkylamide is preferably the N,~-di-Cl to C6 alkyl derivative of a Cl to C20, more preferably Cl to C4 alkanoic acid~ In particular the process is applicable to the production of dimethylacetamide by the reaction of dimethylamine with methyl acetate and dimethyl-formamide by the reaction of dimethylamine with carbon monoxide, The catalyst residues comprise alkali metal ions which have usually been added to the amide-forming process as an alkoxide, e.g. a Cl to Cs alkoxide such as a methoxide.
Sodium or potassium ions are the most usual alkali metal ions present, the most popular catalyst being sodium methoxide.
The crude product of the ~,N-dialkylamide-forming process comprises the amide, alcohol from the catalyst, alkali metal ions and unchanged reactant(s). It is advantageous that unchanged amine reactant be kept to a minimum because it too is absorbed on the cation exchange resin and, although this in effect helps in the refining of the crude product, is necessitates the use of an increased amount of resin. Generally the crude product contains at least 40% by weight of the dialkyl ~1 . 2fJ~ ~7 ~OSZ818 amide and up to 1.0~ by weight unchanged amine.
The cation exchange resin should be resistant to organic solvents and may be chosen from the range of commercially available resins which are capable of alkali metal ion adsorption, principally the strongly acid exchangers such as sulphonated styrene-divinylbenzene copolymers and the more weakly acid exchangers such as unsaturated carboxylic acids cross-linked with a cross-linking agent such as divinyIbenzene, or the phenolic con-densation product exchangers. Examples of suitableresins include 'AMBERLYST' A15 and IAMBERLITEI 200H, (AMBERLYST and AMBERLITE are trademarks). The exchange resin is suitably in its hydrogen form and may be used as a granular bed through which percolates the crude reaction product preferably at a temperature in the range 0 to 200C, more preferably 20 to 50 C. The rate of passage of the crude product through the bed is suitably 0.01 to 50, preferably 0.1 to 5, more preferably 1 to 2.5 litres crude product/hour/litre resin bed. When the resin becomes saturated with alkali metal ions it may be regenerated by treatment with an acid solution, e.g.
with sulphuric acid. For the regeneration process the resin is first preferably washed with a C1 to C4 alkanol such as methanol, then with water, acid, water again and finally once more with the alkanol.
The process of the invention is particularly well adapted to continuous operation with ths crude product from the N,N-dialkylamide process being fed con-J,os~,~s~8 tinuously to the resin One advantageous modificakion isto use two resin beds in parallel, one being in use while the other is being regenerated.
The invention will now be further described with reference to the following Examples.
A two litre stirred reactor was provided with a cruciform stirrer through which gaseous dimethylamine could be introduced, a liquid inlet line through which could be metere~methyl acetate/methanol azeotrope and sodium methoxide/
methanol catalyst solution, and a water batch which enabled the reactor to be maintained at 45C. A constant level device enabled material to be continuously withdrawn from the reactor so as to maintain a constant level therein, the product withdrawn being cooled in a water cooled condenser and then fed continuously to a bed of AMBERLYST A15 resin. The resin bed had a packed volume of 1100 mls. and the reaction product passed through it at a rate of 1.8 bed volumes per hour. Every two hours the resin bed was regenerated by washing in turn with methanol, water, 6~ sulphuric acid, water and methanol again.
The reactants comprised methanol/methyl acetate azeotrope at a feed rate of 1281 grams/hour (1057 grams methyl acetate and 224 grams methanol) and dimethylamine at a feed rate of 445 grams/hour. The catalyst solution comprised sodium methoxide in methanol which was - - -H.26357 105Z8~8 metered to the reaction vessel at a rate of 150 grams/
hour (30 grams sodium methoxide and 120 grams methanol, i.e. o.68~ wt/wt. sodium).
The product leaving the resin bed had the following analysis:-dimethylamine : 0.3% w/w methyl acetate : 12.1% w/w methanol : 42.0~ w/w dimetllylacetamido : 45.0% w/w sodium : lcss ~han 1() p.p. m.
i.e. the sodium level had been reduced from o.68% w/w to less than 0.001% w/w.
Example 1 was repeated replacing the bed of ~AMBERLYST` 15 by ~AMBERLITEI 200~ a strongly acidic cation exchange resin. Once again the sodium content of the crude product was reduced from o.68% w/w to less than lO p.p.m.
Methanol (170 grams, 5.3 moles), sodium methoxide (0.132 moles, 35.4 grams of a 20% wt/wt.
solution in methanol) and dimethylamine (300 grams, 6.7 moles) were charged to a stirred 1 litre autoclave. Car-bon monoxide was introduced to a pressure of 100 p.s.i.g.
and the reactants were heated, with stirring, to 70 C.
At this point the pressure was increased to 300 p.s.i.g.
_ 6 -~0~'~8~8 with carbon monoxide and the temperature and pressure maintained for a period of 2 3/4 hours when it was noted that the carbon monoxide uptake had stopped. The reactants were cooled and 708.8 grams of clear pale yellow product was collected in an ice cold receiver. The product had the following analysis:-dimethylamine : less than 0.5% wt/wt.methyl formate : 9.4% wt/wt.
methanol : 18.2% wt/wt.
dimethylformamide : 67.0% wt/wt.
water : less than 0.01% wt/wt.
sodium : 0.43% wt/wt.
The crude product was treated with 'AMBERLYST' 15 resin by the method described in Example 1. By this technique the sodium content was reduced to less than 10 p.p.m.
THE PRESE~T INVENTION relates to the manufacture of amides, in particular to the manufacture of N,N-dialkylamides.
~ ,~-dialkylamides such as dimethylformamide and dimethylacetamide may be manufactured by reaction of an alkyl ester of the relevant acid with a dialkylamine, e.g.
methyl formate or methyl acetate with dimethylamine. In the case of the formate the reaction is very rapid and no catalyst is required, but the acetate is far slower and for commercial operation requires a catalyst, conventionally an alkali metal alkoxide such as sodium methoxide. An alternative manufacturing process for the ~,~-dialkylamides, especially for dimethylformamide, involves the reaction of the dialkylamine, e.g. dimethylamine with carbon monoxide under pressure and again a catalyst such as an alkali metal alkoxide is used.
Both types of process using an alkali metal alkoxide catalyst yield a crude product which may contain the N,~-dialkyl-amide, alcohol from the alkali metal alkoxide, alkali metal ions, unchanged dialkylamine and, in the case of an ester reactant, unchanged ester. This mixture is usually refined by distillation but the alkali metal ions must be removed first to avoid precipitation of solids in the distillation boiler and to destroy the catalytic effect of the alkoxide.
Conventionally, the alkali metal is removed by acid and/or water washing but this procedure is time consuming and inevitably results in losses of organic material as well as presenting an effluent disposal problem We have now devised an alternative and improved method of catalyst removal.
According to the invention alkali metal catalyst 0 residues are removed from the crude product of an ~ 5~,~8~.8 dialkylamide-forming process by contacting the crude product with a cation exchange resin, The ~,~-dialkylamide is preferably the N,~-di-Cl to C6 alkyl derivative of a Cl to C20, more preferably Cl to C4 alkanoic acid~ In particular the process is applicable to the production of dimethylacetamide by the reaction of dimethylamine with methyl acetate and dimethyl-formamide by the reaction of dimethylamine with carbon monoxide, The catalyst residues comprise alkali metal ions which have usually been added to the amide-forming process as an alkoxide, e.g. a Cl to Cs alkoxide such as a methoxide.
Sodium or potassium ions are the most usual alkali metal ions present, the most popular catalyst being sodium methoxide.
The crude product of the ~,N-dialkylamide-forming process comprises the amide, alcohol from the catalyst, alkali metal ions and unchanged reactant(s). It is advantageous that unchanged amine reactant be kept to a minimum because it too is absorbed on the cation exchange resin and, although this in effect helps in the refining of the crude product, is necessitates the use of an increased amount of resin. Generally the crude product contains at least 40% by weight of the dialkyl ~1 . 2fJ~ ~7 ~OSZ818 amide and up to 1.0~ by weight unchanged amine.
The cation exchange resin should be resistant to organic solvents and may be chosen from the range of commercially available resins which are capable of alkali metal ion adsorption, principally the strongly acid exchangers such as sulphonated styrene-divinylbenzene copolymers and the more weakly acid exchangers such as unsaturated carboxylic acids cross-linked with a cross-linking agent such as divinyIbenzene, or the phenolic con-densation product exchangers. Examples of suitableresins include 'AMBERLYST' A15 and IAMBERLITEI 200H, (AMBERLYST and AMBERLITE are trademarks). The exchange resin is suitably in its hydrogen form and may be used as a granular bed through which percolates the crude reaction product preferably at a temperature in the range 0 to 200C, more preferably 20 to 50 C. The rate of passage of the crude product through the bed is suitably 0.01 to 50, preferably 0.1 to 5, more preferably 1 to 2.5 litres crude product/hour/litre resin bed. When the resin becomes saturated with alkali metal ions it may be regenerated by treatment with an acid solution, e.g.
with sulphuric acid. For the regeneration process the resin is first preferably washed with a C1 to C4 alkanol such as methanol, then with water, acid, water again and finally once more with the alkanol.
The process of the invention is particularly well adapted to continuous operation with ths crude product from the N,N-dialkylamide process being fed con-J,os~,~s~8 tinuously to the resin One advantageous modificakion isto use two resin beds in parallel, one being in use while the other is being regenerated.
The invention will now be further described with reference to the following Examples.
A two litre stirred reactor was provided with a cruciform stirrer through which gaseous dimethylamine could be introduced, a liquid inlet line through which could be metere~methyl acetate/methanol azeotrope and sodium methoxide/
methanol catalyst solution, and a water batch which enabled the reactor to be maintained at 45C. A constant level device enabled material to be continuously withdrawn from the reactor so as to maintain a constant level therein, the product withdrawn being cooled in a water cooled condenser and then fed continuously to a bed of AMBERLYST A15 resin. The resin bed had a packed volume of 1100 mls. and the reaction product passed through it at a rate of 1.8 bed volumes per hour. Every two hours the resin bed was regenerated by washing in turn with methanol, water, 6~ sulphuric acid, water and methanol again.
The reactants comprised methanol/methyl acetate azeotrope at a feed rate of 1281 grams/hour (1057 grams methyl acetate and 224 grams methanol) and dimethylamine at a feed rate of 445 grams/hour. The catalyst solution comprised sodium methoxide in methanol which was - - -H.26357 105Z8~8 metered to the reaction vessel at a rate of 150 grams/
hour (30 grams sodium methoxide and 120 grams methanol, i.e. o.68~ wt/wt. sodium).
The product leaving the resin bed had the following analysis:-dimethylamine : 0.3% w/w methyl acetate : 12.1% w/w methanol : 42.0~ w/w dimetllylacetamido : 45.0% w/w sodium : lcss ~han 1() p.p. m.
i.e. the sodium level had been reduced from o.68% w/w to less than 0.001% w/w.
Example 1 was repeated replacing the bed of ~AMBERLYST` 15 by ~AMBERLITEI 200~ a strongly acidic cation exchange resin. Once again the sodium content of the crude product was reduced from o.68% w/w to less than lO p.p.m.
Methanol (170 grams, 5.3 moles), sodium methoxide (0.132 moles, 35.4 grams of a 20% wt/wt.
solution in methanol) and dimethylamine (300 grams, 6.7 moles) were charged to a stirred 1 litre autoclave. Car-bon monoxide was introduced to a pressure of 100 p.s.i.g.
and the reactants were heated, with stirring, to 70 C.
At this point the pressure was increased to 300 p.s.i.g.
_ 6 -~0~'~8~8 with carbon monoxide and the temperature and pressure maintained for a period of 2 3/4 hours when it was noted that the carbon monoxide uptake had stopped. The reactants were cooled and 708.8 grams of clear pale yellow product was collected in an ice cold receiver. The product had the following analysis:-dimethylamine : less than 0.5% wt/wt.methyl formate : 9.4% wt/wt.
methanol : 18.2% wt/wt.
dimethylformamide : 67.0% wt/wt.
water : less than 0.01% wt/wt.
sodium : 0.43% wt/wt.
The crude product was treated with 'AMBERLYST' 15 resin by the method described in Example 1. By this technique the sodium content was reduced to less than 10 p.p.m.
Claims (9)
1. A process for the production of a N,N-dimethyl-amide selected from the group consisting of N,N'-dimethyl-formamide and N,N-dimethylacetamide in which dimethylamine is reacted with carbon monoxide or methyl acetate in the presence of sodium or potassium ions to provide a crude pro-duct comprising said amide, coproduct methanol, sodium or potassium ions and unchanged reactants, said crude product being fed continuously to a cation exchange resin held at a temperature of 0° to 200°C, the rate of passage of the crude product through the bed being 0.01 to 50 litres/hour/litre of resin bed, whereby the sodium or potassium ions are substanti-ally removed from said crude product.
2. A process as claimed in Claim 1 in which the crude product contains at least 40% by weight of the N,N-dimethylamide.
3. A process as claimed in Claim 1 in which the cation exchange resin is 'AMBERLYST' A15 or 'AMBERLITE' 200H.
4. A process as claimed in Claim 1 in which the cation exchange resin is in its hydrogen form.
5. A process as claimed in Claim 1 in which the temperature is in the range 20 to 50°C.
6. A process as claimed in Claim 1 in which the crude product percolates through a bed of the resin, the rate of passage of the crude product throuyh the bed being 0.1 to 5 litres crude product/hour/litre of resin bed.
7. A process as claimed in Claim 1 in which the resin is regenerated by treatment with an acid solution.
8. A process as claimed in Claim 7 in which the resin is first washed with a C1 to C4 alkanol, then with water, acid, water again and finally once more with the alkanol.
9. A process as claimed in Claim 1 in which dimethylacetamide or dimethylformamide are produced using a sodium alkoxide catalyst and the sodium residues are re-moved from the crude product by contacting the crude product with a strongly acid cation exchange resin.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3736773A GB1469514A (en) | 1973-08-07 | 1973-08-07 | Manufacture of n,n-dialkylamides |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1052818A true CA1052818A (en) | 1979-04-17 |
Family
ID=10395921
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA206,346A Expired CA1052818A (en) | 1973-08-07 | 1974-08-06 | Manufacture of amides |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5076016A (en) |
| BE (1) | BE818397A (en) |
| BR (1) | BR7406443D0 (en) |
| CA (1) | CA1052818A (en) |
| DE (1) | DE2437702A1 (en) |
| ES (1) | ES429041A1 (en) |
| FR (1) | FR2240208B1 (en) |
| GB (1) | GB1469514A (en) |
| IT (1) | IT1017949B (en) |
| NL (1) | NL7410551A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101993386A (en) * | 2010-11-03 | 2011-03-30 | 天津大学 | Method for preparing electronic-grade N, N-dimethylformamide by ion exchange resin method |
| CN111470997A (en) * | 2020-04-26 | 2020-07-31 | 安庆市鑫祥瑞环保科技有限公司 | Method for recovering DMF waste liquid |
-
1973
- 1973-08-07 GB GB3736773A patent/GB1469514A/en not_active Expired
-
1974
- 1974-08-01 BE BE147210A patent/BE818397A/en not_active IP Right Cessation
- 1974-08-05 DE DE19742437702 patent/DE2437702A1/en not_active Withdrawn
- 1974-08-06 NL NL7410551A patent/NL7410551A/en not_active Application Discontinuation
- 1974-08-06 FR FR7427275A patent/FR2240208B1/fr not_active Expired
- 1974-08-06 BR BR644374A patent/BR7406443D0/en unknown
- 1974-08-06 JP JP9018874A patent/JPS5076016A/ja active Pending
- 1974-08-06 IT IT2604274A patent/IT1017949B/en active
- 1974-08-06 CA CA206,346A patent/CA1052818A/en not_active Expired
- 1974-08-07 ES ES429041A patent/ES429041A1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1469514A (en) | 1977-04-06 |
| DE2437702A1 (en) | 1975-02-13 |
| FR2240208B1 (en) | 1979-10-05 |
| FR2240208A1 (en) | 1975-03-07 |
| IT1017949B (en) | 1977-08-10 |
| JPS5076016A (en) | 1975-06-21 |
| BE818397A (en) | 1975-02-03 |
| NL7410551A (en) | 1975-02-11 |
| BR7406443D0 (en) | 1975-05-27 |
| ES429041A1 (en) | 1976-08-16 |
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