CA1098535A - Method for the preparation of esters of carbonic acid - Google Patents
Method for the preparation of esters of carbonic acidInfo
- Publication number
- CA1098535A CA1098535A CA286,560A CA286560A CA1098535A CA 1098535 A CA1098535 A CA 1098535A CA 286560 A CA286560 A CA 286560A CA 1098535 A CA1098535 A CA 1098535A
- Authority
- CA
- Canada
- Prior art keywords
- reaction
- esters
- preparation
- carbonic acid
- salt
- 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
- C07C68/00—Preparation of esters of carbonic or haloformic acids
- C07C68/01—Preparation of esters of carbonic or haloformic acids from carbon monoxide and oxygen
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)
- Catalysts (AREA)
Abstract
METHOD FOR THE PREPARATION OF ESTERS
OF CARBONIC ACID . -ABSTRACT OF THE DISCLOSURE . -Carbonic acid esters are prepared by reacting the alcohol concerned with oxygen and carbon monoxide in the presence of a catalyst which is a salt of a metal belonging to the Groups IB, IIB and VIII of the Periodic Table: the least possible number of inorganic anions is desirable in order to reduce the acidity of the environment as far as possible. The salts of monovalent copper are preferred and high yields and selectivities are obtained.
OF CARBONIC ACID . -ABSTRACT OF THE DISCLOSURE . -Carbonic acid esters are prepared by reacting the alcohol concerned with oxygen and carbon monoxide in the presence of a catalyst which is a salt of a metal belonging to the Groups IB, IIB and VIII of the Periodic Table: the least possible number of inorganic anions is desirable in order to reduce the acidity of the environment as far as possible. The salts of monovalent copper are preferred and high yields and selectivities are obtained.
Description
This invention relates to a method for the pre-paration of esters of carbonic acid~ such method compri-sing the step of reacting the alcohol~ which is intended to be estcrified~ with carbon mono~ide and oxygen in the presence of a catalyst which is a metallic salt, preferably a copper salt~ with its metallic ion bound to the least possible number of inorganic anions.
Esters of carbonic acid are known in the art:
they find a use as solvents and as polymerizing agents for the transesterification reactions with glycols and bisphenols in the production of polycarbonates.
The methods which are most commonly employed for t~e preparation of the esters in question are based on the reaction between the alcohol and phosgene or chloro-formates in the presence of bases~ these latter being appropriately selected from among the series of the hyclroxide~ and carbonates oE alkali metals and alkaline earth metals~ or piridine and other organic bases~ The dangers and the poor indus~rial adaptability of these methods are such that no doub-ts are left in this connection.
Attempts have been made to skip the known waysj ~ut with poor results. For example~ the Japanese Patent N 11 129 described the~preparation of the carbonate ester by react-~~ing the alcohol concerned with carbon monoxide in the presence of cupric ions: the use of salts of bivalent copoer~ especially halides~ is emphasi~ed in that patent.
In this case~ the oarbonate yiel~ are extremely low andg in addition~ the formation of onsiderabIe amoun-ts of *he alkyl halide~ ether and haloid aoid~is experienced~ so that the pH of the solu*ion becomes considerably acidic.
As a whole~ it is not possible to envisage a transfer of such a procedure to an industrial scale.
v,~7 3~j The same Applicants ~hereof are owners of an Italian Patent ~ 898 077~ ~hich relates to a method or the preparation of esters of t~e carbonic acid~
which is based on the reac-tion between the alcohol~ carbon monoxide and oxygen~ carrled out in the presence of a catalyst system composed by complexes of metals which are capable, by oxy-reduction~ of displaying two valency statesO
The results are no doubt satisfactory~ but the use of complexes is affected by a few defects~ especially if viewed with the prospect of transfer on an industrial scale. Quite apart from the higher cost of the complex catalyst system~9 these gencrally exhibit a certain sensitivity to the action of ~ater and carbon dioxide which are formed together with the carbonate in the course of the reaction~ a fact :
which imposes a low conversion of the alcohol. There are difficulties~ moreover~ in the separation of the reaction products and more particularly of water and carbonate from the reactor efEluent and from the ~omogeneous catalyst inasmuch as the ligand is normally an organic base and brings about a certain hydrolysis of the ester due to the water which is present in the system.
We have now found that the same reaction is feasible~
under certain conditions~ in the presence of simple metal salts~ and this fact is most surprising since it was known 2S heretofore ~hat~ with such a catalyst system~ only poly-functional alcohols were capable o- reacting to give esters -~
at the carbonic acid (see the Italian Patent N 926 748). `
The subject-matter of the present invention is a -method for the preparation of esters of the carbonic acid comprising the step~ as outlined above~ of reacting the alcohol concerned with carbon mono~ide and o~ygen in the presence of a salt of a metal belonging to the groups IB~
. IIB and VI~ of the Periodic Table with its metal ion bound to the least possible number of inorganic anions.
The use of copper salts has proven to be particularly advanta-.
~, , .
geo~s. The reaction pattern can thus be sw-~arized :
Esters of carbonic acid are known in the art:
they find a use as solvents and as polymerizing agents for the transesterification reactions with glycols and bisphenols in the production of polycarbonates.
The methods which are most commonly employed for t~e preparation of the esters in question are based on the reaction between the alcohol and phosgene or chloro-formates in the presence of bases~ these latter being appropriately selected from among the series of the hyclroxide~ and carbonates oE alkali metals and alkaline earth metals~ or piridine and other organic bases~ The dangers and the poor indus~rial adaptability of these methods are such that no doub-ts are left in this connection.
Attempts have been made to skip the known waysj ~ut with poor results. For example~ the Japanese Patent N 11 129 described the~preparation of the carbonate ester by react-~~ing the alcohol concerned with carbon monoxide in the presence of cupric ions: the use of salts of bivalent copoer~ especially halides~ is emphasi~ed in that patent.
In this case~ the oarbonate yiel~ are extremely low andg in addition~ the formation of onsiderabIe amoun-ts of *he alkyl halide~ ether and haloid aoid~is experienced~ so that the pH of the solu*ion becomes considerably acidic.
As a whole~ it is not possible to envisage a transfer of such a procedure to an industrial scale.
v,~7 3~j The same Applicants ~hereof are owners of an Italian Patent ~ 898 077~ ~hich relates to a method or the preparation of esters of t~e carbonic acid~
which is based on the reac-tion between the alcohol~ carbon monoxide and oxygen~ carrled out in the presence of a catalyst system composed by complexes of metals which are capable, by oxy-reduction~ of displaying two valency statesO
The results are no doubt satisfactory~ but the use of complexes is affected by a few defects~ especially if viewed with the prospect of transfer on an industrial scale. Quite apart from the higher cost of the complex catalyst system~9 these gencrally exhibit a certain sensitivity to the action of ~ater and carbon dioxide which are formed together with the carbonate in the course of the reaction~ a fact :
which imposes a low conversion of the alcohol. There are difficulties~ moreover~ in the separation of the reaction products and more particularly of water and carbonate from the reactor efEluent and from the ~omogeneous catalyst inasmuch as the ligand is normally an organic base and brings about a certain hydrolysis of the ester due to the water which is present in the system.
We have now found that the same reaction is feasible~
under certain conditions~ in the presence of simple metal salts~ and this fact is most surprising since it was known 2S heretofore ~hat~ with such a catalyst system~ only poly-functional alcohols were capable o- reacting to give esters -~
at the carbonic acid (see the Italian Patent N 926 748). `
The subject-matter of the present invention is a -method for the preparation of esters of the carbonic acid comprising the step~ as outlined above~ of reacting the alcohol concerned with carbon mono~ide and o~ygen in the presence of a salt of a metal belonging to the groups IB~
. IIB and VI~ of the Periodic Table with its metal ion bound to the least possible number of inorganic anions.
The use of copper salts has proven to be particularly advanta-.
~, , .
geo~s. The reaction pattern can thus be sw-~arized :
2 R011 ~ C0 + 1 0 ~ R 0 C 0 1~-~ 1120 whercin R is a hydrocarbonaceous radical selected among the alkyl~ aryl or cycloalky:l. radicals: the reaction is carried out by dispersing or dissolving the salt of the metal in question in a solvent which can be the alcohol as itself or another inert diluent.
The advanta~e s*el~nin~ from the use of salts having a res-~rictc~ lluml)er of inor6allic aniolls is consiclerable~
since there is-no formation of a hi~h acidi-ty during progress of the reaction. The system remains at p~-l values of a weakly acidic character during the entire reac-tion run~ so th.at the reaction itself is not impaired in any wise and proceeds to very high carbonate ester yleld. with-out experiencing the formation of any appreciable quanti-tles of by-products.
As outlined above~ the reaction is carried out elther by dispersing or ~issolvi:llg the metal sal-t in a solvent medium: through the dispersion or so:Lution thus ; :20 obtained a stream of C0 and 2 is delivered~ carbon monoxide and oxygen bein~ fed either separately or admixed together~
either continuously or in alternating cycles.
The expected product is separated from the reaction mixture by means oÇ simple physical procedures~ In the case of dispersions~ for example~ filtration is sufficient ko remove the catalyst~ thus separating the solution which contains the carbonate: the latter shall then be recovered by rectification or crystall.izatior.
The method of the invention can be carried out within a wide range of pressures and temperatures and *he kop limits are a function~ for example~ of the stabilit~ of the compounds which are empJoyed~ Generally speakin~ the working temperatures vary from 70C to 200C~ the C0 and 2 pressures bein~ higher than the atmospherical pressure.
~ .
~ .
The advanta~e s*el~nin~ from the use of salts having a res-~rictc~ lluml)er of inor6allic aniolls is consiclerable~
since there is-no formation of a hi~h acidi-ty during progress of the reaction. The system remains at p~-l values of a weakly acidic character during the entire reac-tion run~ so th.at the reaction itself is not impaired in any wise and proceeds to very high carbonate ester yleld. with-out experiencing the formation of any appreciable quanti-tles of by-products.
As outlined above~ the reaction is carried out elther by dispersing or ~issolvi:llg the metal sal-t in a solvent medium: through the dispersion or so:Lution thus ; :20 obtained a stream of C0 and 2 is delivered~ carbon monoxide and oxygen bein~ fed either separately or admixed together~
either continuously or in alternating cycles.
The expected product is separated from the reaction mixture by means oÇ simple physical procedures~ In the case of dispersions~ for example~ filtration is sufficient ko remove the catalyst~ thus separating the solution which contains the carbonate: the latter shall then be recovered by rectification or crystall.izatior.
The method of the invention can be carried out within a wide range of pressures and temperatures and *he kop limits are a function~ for example~ of the stabilit~ of the compounds which are empJoyed~ Generally speakin~ the working temperatures vary from 70C to 200C~ the C0 and 2 pressures bein~ higher than the atmospherical pressure.
~ .
~ .
3~j `
All the working details will be set forth in -the ensuing illustrative examples which~ however~ are not to be construed as limitations of the invention.
EXAMPLE
A 200-ml~ Teflon-lined autoclave has been charged wi~h 100 mls MeOH and 18 grams of CuBr~ The system is oxidized with 2 at 60C under a pressure of 2 of 5 atmospheres (gauge) for 90 mins. Subsequen-tly~ CO has been fed-in until a pressure of 12 atmospheres (gauge) has been attained and the temperature has been brought to 80~Co Carbon monoxide is replaced in the system as it is being used up in the reaction so as not to alter the-total pressure. The reaction was completed after 30 mins.
and the solution analyzed by gas chromatographical analysis.
There have been obtained a complete conversion of the copper and a selectivity of 95% of dimethyl carbonate and the residual copper oxidized the carbon monoxide -to carbon dioxide. There have been carried out 4 similar subsequent cycles and only a sli~rht increase of select-ivity of C02 in time was observed. II1 the fourth cycle the molar ratio C02/dimethyl carbonate was l to 90 -- .
In the apparatus described in Example 1 there have been charged 100 mls methanol and 20 grams of CuCl and the system has been oxidized with 2 to 800C and under - 10 atmospheres (gauge) for 60 mins. Subsequentlyg CO has.
been fed-in under 30 atmospheres (gauge) constant pres-sure and the temperature has been raised to 100C. The reaction lasted as long as 9Q minutes. On completion of the reaction the copper was still in a completely reduced form~ The c~methyl carbonate yield was 95%~ whereas the remaining copper oxidized the CO to CO20 The selectivity relative to methanol was totalO
EXAMPLE_ ~
In the apparatus of Example l there have been cha~d .
. 5~ .
, .
16 J 4 grams of CuC10~ and 26 grams of methanol. Tlle system has been oxidi~ed with 02 to 100C and under a pressure of 5 atmospheres (gauge) during 20 minu-tes and reduced with CO under 50 atmospheres (gauge) at 100C for 2 hours. On completion of th~ reaction the - copper was in a totally reduced form. The dimethyl carbo-nate yield was over 95%. The remaining copper oxidized CO to C02 and the selectivity relative to methanol was total.
EXAMPLE _4 The apparatus of Example l was charged with 15 grams of methanol and 10 grams of CuC12o To the system there have been added 3~9 grams of so~ium methylate in 20 grams methanol~ to such an extent as to neutralize either of the two chlorine ions bound to the copper. The reaction mixture has been brougllt to 100C and placed under 60 atmo-sphere tgauge) of CO. After two hours a complete reduction of copper -to CuCl was e~periencecL and methyl carbonate was obtained with a yield as high as 90% approxO of theory.
There has been noted the formation of small amounts of ~ethyl chloride and dimethyl ether~ but at any rate less than 0002%.
.
A 6-liter~ ceramic-lined autoclave was charged with 3 liters of methanol and 480 grams of CuCl~ the tempera-ture was raised to 70C and 2 was introduced under a pressure of 8 atmospheres (gauge) until a complete oxida-tion o-E the copper was achieved~ that which was completed within an hour approximately. Subsequently~ the excess f 2 was vented and CO introduced under a pressure of 15 atmospheres (gauges) the pressure being kept constant.
Within 3 hours the ~onversion of copper was total, The selectivity relative to dimethyl carbonate was over 95%~
the remaining copper oxxdized CO to C02~ ThP selectivity relative to methanol was total. In the three subsequent .
6.
- .
~8~3S;
cycles the trend oE the reaction was substantially the same as before, Qnly a slight increase of C02 between a reaction cycle and the next was observed.
The apparatus described in Example 5 has been charged with 3 liters of methanol and 480 grams of CuCl~
the temperature raised to 100C and 2 was fed-in under a pressure of 10 atmospheres (gauge) until a complete oxidation of copper was achievedg that which took about 30 minutesO The excess oxygen was vented and C0 was fed-in .
under a pressure of 20 atmospheres (gauge), the tempera-ture being maintained at 120C. After 20 minsa the reaction was completed and the selectivity relative to dimethyl carbonate was 92%. The residual copper oxidized C0 to EXAMPL~ 7 The apparatus described in Example 5 was charged with 3 liters of methanol and 480. grams of CuCl. The thermostatically controlled system was fed at 102C with ~ :
150 normal liters an hour of C0 and 50 normal liters an hour of 2 simultaneously under a total pressure of 30 ...
atmospheres (gauge)~ The system was continually vented by discharging 50 normal liters hourly of a ~as mixture which was essentially composed by 97% C0~ from 2% to 3%
C02 and from 0.1% to o4% 2~ after a 4-hour run the conversion of methanol was 30% and the selecti~ity rela-tive to dimethyl carbonate was 95%.
EXA ~
The apparatus described in ~xample 1 was charged with 16 grams CuS0 and 30 mls methanol: to the system there was added 308 grams of lithium methoxide in 10 mls methanol so as to neutralize one half of the sulphate ion. C0 was fed-in under 50 atmospheres (gauge) and the tempera-ture was brought to 110C. After two hours the copper :-.
was entirely reduced to Cu2S04. Dimethyl carbonate was .
3~
obtained with a yield of 75% relative to copperO the remaining copper had oxidized CO to CO~. The selecti-Yity relative to methanol was total~
.
, ' ' ' , ' , , - ~ .
.
- , . . :' ~ ' i ,' ~ ' ' ' ,: . ,., . ~ .
All the working details will be set forth in -the ensuing illustrative examples which~ however~ are not to be construed as limitations of the invention.
EXAMPLE
A 200-ml~ Teflon-lined autoclave has been charged wi~h 100 mls MeOH and 18 grams of CuBr~ The system is oxidized with 2 at 60C under a pressure of 2 of 5 atmospheres (gauge) for 90 mins. Subsequen-tly~ CO has been fed-in until a pressure of 12 atmospheres (gauge) has been attained and the temperature has been brought to 80~Co Carbon monoxide is replaced in the system as it is being used up in the reaction so as not to alter the-total pressure. The reaction was completed after 30 mins.
and the solution analyzed by gas chromatographical analysis.
There have been obtained a complete conversion of the copper and a selectivity of 95% of dimethyl carbonate and the residual copper oxidized the carbon monoxide -to carbon dioxide. There have been carried out 4 similar subsequent cycles and only a sli~rht increase of select-ivity of C02 in time was observed. II1 the fourth cycle the molar ratio C02/dimethyl carbonate was l to 90 -- .
In the apparatus described in Example 1 there have been charged 100 mls methanol and 20 grams of CuCl and the system has been oxidized with 2 to 800C and under - 10 atmospheres (gauge) for 60 mins. Subsequentlyg CO has.
been fed-in under 30 atmospheres (gauge) constant pres-sure and the temperature has been raised to 100C. The reaction lasted as long as 9Q minutes. On completion of the reaction the copper was still in a completely reduced form~ The c~methyl carbonate yield was 95%~ whereas the remaining copper oxidized the CO to CO20 The selectivity relative to methanol was totalO
EXAMPLE_ ~
In the apparatus of Example l there have been cha~d .
. 5~ .
, .
16 J 4 grams of CuC10~ and 26 grams of methanol. Tlle system has been oxidi~ed with 02 to 100C and under a pressure of 5 atmospheres (gauge) during 20 minu-tes and reduced with CO under 50 atmospheres (gauge) at 100C for 2 hours. On completion of th~ reaction the - copper was in a totally reduced form. The dimethyl carbo-nate yield was over 95%. The remaining copper oxidized CO to C02 and the selectivity relative to methanol was total.
EXAMPLE _4 The apparatus of Example l was charged with 15 grams of methanol and 10 grams of CuC12o To the system there have been added 3~9 grams of so~ium methylate in 20 grams methanol~ to such an extent as to neutralize either of the two chlorine ions bound to the copper. The reaction mixture has been brougllt to 100C and placed under 60 atmo-sphere tgauge) of CO. After two hours a complete reduction of copper -to CuCl was e~periencecL and methyl carbonate was obtained with a yield as high as 90% approxO of theory.
There has been noted the formation of small amounts of ~ethyl chloride and dimethyl ether~ but at any rate less than 0002%.
.
A 6-liter~ ceramic-lined autoclave was charged with 3 liters of methanol and 480 grams of CuCl~ the tempera-ture was raised to 70C and 2 was introduced under a pressure of 8 atmospheres (gauge) until a complete oxida-tion o-E the copper was achieved~ that which was completed within an hour approximately. Subsequently~ the excess f 2 was vented and CO introduced under a pressure of 15 atmospheres (gauges) the pressure being kept constant.
Within 3 hours the ~onversion of copper was total, The selectivity relative to dimethyl carbonate was over 95%~
the remaining copper oxxdized CO to C02~ ThP selectivity relative to methanol was total. In the three subsequent .
6.
- .
~8~3S;
cycles the trend oE the reaction was substantially the same as before, Qnly a slight increase of C02 between a reaction cycle and the next was observed.
The apparatus described in Example 5 has been charged with 3 liters of methanol and 480 grams of CuCl~
the temperature raised to 100C and 2 was fed-in under a pressure of 10 atmospheres (gauge) until a complete oxidation of copper was achievedg that which took about 30 minutesO The excess oxygen was vented and C0 was fed-in .
under a pressure of 20 atmospheres (gauge), the tempera-ture being maintained at 120C. After 20 minsa the reaction was completed and the selectivity relative to dimethyl carbonate was 92%. The residual copper oxidized C0 to EXAMPL~ 7 The apparatus described in Example 5 was charged with 3 liters of methanol and 480. grams of CuCl. The thermostatically controlled system was fed at 102C with ~ :
150 normal liters an hour of C0 and 50 normal liters an hour of 2 simultaneously under a total pressure of 30 ...
atmospheres (gauge)~ The system was continually vented by discharging 50 normal liters hourly of a ~as mixture which was essentially composed by 97% C0~ from 2% to 3%
C02 and from 0.1% to o4% 2~ after a 4-hour run the conversion of methanol was 30% and the selecti~ity rela-tive to dimethyl carbonate was 95%.
EXA ~
The apparatus described in ~xample 1 was charged with 16 grams CuS0 and 30 mls methanol: to the system there was added 308 grams of lithium methoxide in 10 mls methanol so as to neutralize one half of the sulphate ion. C0 was fed-in under 50 atmospheres (gauge) and the tempera-ture was brought to 110C. After two hours the copper :-.
was entirely reduced to Cu2S04. Dimethyl carbonate was .
3~
obtained with a yield of 75% relative to copperO the remaining copper had oxidized CO to CO~. The selecti-Yity relative to methanol was total~
.
, ' ' ' , ' , , - ~ .
.
- , . . :' ~ ' i ,' ~ ' ' ' ,: . ,., . ~ .
Claims (5)
1. A method for the preparation of esters of car-bonic acid comprising the step of reacting an alcohol with oxygen and carbon monoxide in the presence of a catalyst which is a salt of a metal belonging to the groups IB, IIB and VIII
of the Periodic Table, said reaction being carried out at a temperature ranging from 70°C to 200°C and under a pressure higher than the air pressure.
of the Periodic Table, said reaction being carried out at a temperature ranging from 70°C to 200°C and under a pressure higher than the air pressure.
2. A method for the preparation of esters of car-bonic acid according to claim 1, wherein the reaction is carried out in the presence of a salt of monovalent copper.
3. A method for the preparation of esters of car-bonic acid according to claim 1, characterized in that the reaction is conducted in the presence of a salt of bivalent copper containing a single inorganic anion.
4. A method according to claim 1, characterized in that the reaction is carried out in the presence of alcohol only as a reaction medium.
5. A method according to claim 1, characterized in that the reaction is carried out in the presence of a diluent which is inert with respect to said reaction.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT27825/76A IT1070574B (en) | 1976-09-30 | 1976-09-30 | PROCEDURE FOR THE PREPARATION OF CARBONIC ACID ESTERS |
| IT27825A/76 | 1976-09-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1098535A true CA1098535A (en) | 1981-03-31 |
Family
ID=11222406
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA286,560A Expired CA1098535A (en) | 1976-09-30 | 1977-09-12 | Method for the preparation of esters of carbonic acid |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS6058739B2 (en) |
| AT (1) | AT368123B (en) |
| BE (1) | BE859272A (en) |
| CA (1) | CA1098535A (en) |
| DE (1) | DE2743690C3 (en) |
| DK (1) | DK157674C (en) |
| FR (1) | FR2366254A1 (en) |
| GB (1) | GB1574188A (en) |
| IT (1) | IT1070574B (en) |
| LU (1) | LU78193A1 (en) |
| NL (1) | NL7710689A (en) |
| SU (1) | SU1115667A3 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0071286B1 (en) * | 1981-07-30 | 1985-08-28 | Shell Internationale Researchmaatschappij B.V. | Process for the preparation of carbonate esters |
| DE3926709A1 (en) * | 1989-08-12 | 1991-02-14 | Basf Ag | METHOD FOR PRODUCING DIALKYL CARBONATES |
| DE3926710A1 (en) * | 1989-08-12 | 1991-02-14 | Basf Ag | METHOD FOR PRODUCING DIALKYL CARBONATES |
| DE4018228A1 (en) * | 1990-06-07 | 1991-12-12 | Henkel Kgaa | FLOWABLE DRILL TREATMENT AGENTS BASED ON CARBONIC DIESTERS |
| DE4138755A1 (en) * | 1991-11-26 | 1993-05-27 | Bayer Ag | METHOD FOR PRODUCING DIALKYL CARBONATES |
| DE4140259A1 (en) * | 1991-12-06 | 1993-06-09 | Basf Ag, 6700 Ludwigshafen, De | METHOD FOR PRODUCING TERTIA AMINOXIDES |
| DE4203796A1 (en) * | 1992-02-10 | 1993-08-12 | Bayer Ag | METHOD FOR PRODUCING DIALKYL CARBONATES |
| DE4325651A1 (en) * | 1993-07-30 | 1995-02-02 | Bayer Ag | Process for the preparation of dialkyl carbonates |
| DE4339977A1 (en) * | 1993-11-24 | 1995-06-01 | Bayer Ag | Process for working up the liquid reaction products from the copper-catalyzed production of dimethyl carbonate |
| DE4344159A1 (en) * | 1993-12-23 | 1995-06-29 | Bayer Ag | Process for the preparation of dimethyl carbonate |
| US6258923B1 (en) | 1999-06-11 | 2001-07-10 | General Electric Company | Method for manufacturing dialkyl carbonate |
-
1976
- 1976-09-30 IT IT27825/76A patent/IT1070574B/en active
-
1977
- 1977-08-25 GB GB35784/77A patent/GB1574188A/en not_active Expired
- 1977-09-12 CA CA286,560A patent/CA1098535A/en not_active Expired
- 1977-09-16 JP JP52110621A patent/JPS6058739B2/en not_active Expired
- 1977-09-27 FR FR7729068A patent/FR2366254A1/en active Granted
- 1977-09-27 SU SU772524854A patent/SU1115667A3/en active
- 1977-09-28 LU LU78193A patent/LU78193A1/xx unknown
- 1977-09-28 DE DE2743690A patent/DE2743690C3/en not_active Expired
- 1977-09-29 AT AT0696277A patent/AT368123B/en not_active IP Right Cessation
- 1977-09-29 NL NL7710689A patent/NL7710689A/en not_active Application Discontinuation
- 1977-09-29 DK DK432077A patent/DK157674C/en not_active IP Right Cessation
- 1977-09-30 BE BE181370A patent/BE859272A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| LU78193A1 (en) | 1978-01-23 |
| DE2743690A1 (en) | 1978-04-06 |
| DE2743690C3 (en) | 1980-01-10 |
| DK432077A (en) | 1978-03-31 |
| AT368123B (en) | 1982-09-10 |
| JPS5344523A (en) | 1978-04-21 |
| ATA696277A (en) | 1982-01-15 |
| DK157674C (en) | 1990-07-09 |
| IT1070574B (en) | 1985-03-29 |
| NL7710689A (en) | 1978-04-03 |
| JPS6058739B2 (en) | 1985-12-21 |
| SU1115667A3 (en) | 1984-09-23 |
| DE2743690B2 (en) | 1979-05-03 |
| FR2366254A1 (en) | 1978-04-28 |
| GB1574188A (en) | 1980-09-03 |
| DK157674B (en) | 1990-02-05 |
| FR2366254B1 (en) | 1980-10-17 |
| BE859272A (en) | 1978-03-30 |
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