DE1768458C3 - - Google Patents

Description

ROCOSR'R "R"'NH f ROH - 1/20, - + - ROCOOR f H ₂ O {S f NR'R "R"'

R, R ', R "and R" can be an alkyl, substituted zeolite), various clays, e.g. B. attapulgite clay, Be alkyl or other suitable radical. certain bentonites and similar water-absorbing dies Oxidation can result in low temperatures. Such absorbents should be used in be present in any way to form the dialkyl carbonate of such a concentration that lead, provided that in the alkanol solution or at least a substantial part of the reaction -dispersion in addition to the adduct a certain means 55 tion resulting water is absorbed. Preferences isi. This can be a water-absorbent way, the additive should remove the entire amount of water be that in the solution or dispersion of the sorb. Generally there will be a concentration Adduct is insoluble and mostly neutral at from about 50 to 250 g of water absorbent per mole the oxidation conditions according to the invention, d. H. of the product used. Such an absorption towards the adduct, the solvent or dispersant can already occur during the reaction leading to the dissolving agent (the alkanol) and the tertiary amine formation of the adduct leads, or may be present as well as against the carbonyl sulfide, sulfur of the solution or dispersion at any time before or during and the dialkyl carbonate. To this end, oxidation can be added, preferably certain anhydrous inorganic salts used at a time when oxidation has not yet occurred e.g. anhydrous calcium sulphate, sodium 65 is strongly in progress, in any case before the oxidation sulfate or zinc sulfate. On the other hand .can is also accomplished. The use of a water absorbent water-absorbent materials are used, the beer-producing agent results in a large yield z. B. finely divided sieves (synthetic and natural - the desired dialkyl carbonate. So it leads

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during the oxidation by absorption of a reaction product (Water) to a predominantly complete reaction.

Instead of the water absorbent or In addition, certain oxidizing agents of the solution or dispersion can also be used during the oxidation added to the product. Such oxidizers are certain salts that accelerate the rate of reaction when the product is oxidized

increased. For example, is an oxidizer in the effective low concentration of about 1 to 15 percent by weight of the adduct is present, then the oxidation can usually occur internally half of 1 to 4 hours, in some cases even in a shorter time. Is the oxidizer present in a far greater concentration; d. H. in a concentration about the molar Equivalent of the add-on, then

ιιαιιυιΐ uvj w * juu «. _v .... - _v

or dispersion with the adduct, the oxidation takes place both in the presence and in the absence of oxygen or air. There is no need to use air or oxygen under superatmospheric conditions

and besides, a large yield of the desired, the oxidizing agent not only improves the yield

supply th dialkyl carbonate. Such salts are in dialkyl carbon and set the duration of the reaction

at least to a certain extent in the solution, but makes further ad-

or dispersion in which the adduct demonstrates oxygen during the reaction. at

hand is. In addition, the cations of the oxy- application of an approximately equimolar concentration

dation means easily their valence, for example 15 tration of the oxidizing agent in the ^ alkanol solution

in the transition from a higher to a lower "

Oxidation level. For this purpose, depending on the solubility of the oxidizing agent used and the alkanol different halo

ssnide, nitrates and sulfates such valency- 20 pressure, z. B. in an autoclave with a stirrer,

changing metals as a solution or dispersion to apply or the solution or dispersion of the

medium used for the adduct, e.g. B. iron, nickel, product of air or oxygen by long

Exposing cobalt, copper, mercury, palladium, platinum and standing. The reaction can take place

Gold or salts of other metals, which are in a similar manner in an open or closed vessel

Respond wisely. As a result, a good yield is carried out very quickly at 25 atmospheric pressure

of the desired products and an accelerating process.

oxidation achieved. The final treatment dtr solution or Particularly suitable oxidizing agents are dispersed, which may contain the dialkyl carbonate depending on which can be carried out as a solution or dispersion at will. For example medium used alkanoi: ferric chloride, nickel-30 can be the entire end product after oxidation Chloride, cobalt chloride, cupric sulfate, cobalt sulfate, initially to separate the liquid from the solid Cuprin nitrate and cobalt nitrate. The oxidant constituents are filtered. Then it can must be present during the oxidation. The oxy-filtrate is fractionally distilled at low temperature dation agent will usually be in proportion, e.g. B. under vacuum. During the distillery winner Concentration, e.g. B. about 1 to 15 weight- 35 rens a slightly higher temperature can be used percent of the starting product, although are used, d. H. a temperature above the tempera also other concentrations can be used for those used for the formation of the product and the oxy. as will be described below. But it is also recommended that the will. A sufficient amount of the oxidant at relatively low pressure and distillation must be present in order to perform a good yield of the 40 low temperature in order for the off-end product and a shortened oxidation period is not reduced if the dialkyl carbonate is used, be achieved. The choice of the particular oxidizing agent will be described to those skilled in the art on the basis of the Claims do not present any difficulty.

The oxidation is carried out, as described, at a low temperature in any suitable manner accomplished. The alkanol solution or dispersion containing the adduct can therefore be used, for example, in a

Temperature of about 25 to 30 C at atmospheric,,

Pressure exposed 1 to 4 weeks to oxygen or air 50 methylamine in 300 cm ^{3 of} methanol at 25 C and through. Bubbling carbonyl sulfide by the Tn-but it is recommended that the oxidation to accelerate methyiamin-methanol solution at 30 ⁰ C during gene so that the process economical. In a period of 30 minutes for absorption for this purpose, the alkanol solution or dispersant of approximately 40 g of carbonyl sulfide can be prepared with the adduct and the selected additive, which was 55%. After adding a water-absorbing agent from a water-absorbing agent and / or an oxidizing agent, this solution was an oxidizing agent or both, in an autoclave equipped with a stirring device, preferably in an autoclave with an autoclave with stirring at 53 ° C. Acid in a stirrer, and under an excess pressure of 4.2 kg / cm ² within 24 hours of oxygen, z. B. at an overpressure of 2.8 to 60 the oxidized. After the oxidation, the solution was ^{treated at 5.25 kg / cm 2} for about 2 to 24 hours. withdrawn from the autoclave, the precipitated free If there is an absorbent for water, sulfur and the water absorbent, this process step can usually be nitrated in 24 hours and the filtrate obtained can be completed under vacuum at the. The Oxydationsdauer can be about 20 ⁰ C fractionally distilled to Dijedoch formed, as already mentioned, considerably shortened methylcarbonate 65, excess methanol and riwerden I, when one of the oxidation specified methylamine to separate from each other. From the effective concentration of the agent, Table 1 shows the water-absorbing agents used in the various water-absorbing agents used as the oxidizing agent is the rate of oxidation

The method according to the invention will now be explained in more detail using exemplary embodiments.

example 1

It became a solution of one of trimethylamine-methanol-carbonyl sulfide existing adduct is used in methanol, which is obtained by dissolving 45 g of tri-

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and oxidizing agents and the yield of dimethyl carbonal as a percentage of the theoretical value.

Table 1

attempt water
absorbent Oxidation yield
in the medium medium Thcoiie la 100 g anhydrous Sodium sulfate - 25th 1 b 100 g anhydrous Calcium sulfate - 35 Ic 100 g anhydrous 1 g of water Calcium sulfate free CoCI ₂ 75 Id - 1 g of water free CoCl ₂ 75 Ie IUu g anhydrous 200 g attapul Calcium sulfate gitton 20th If 100 g anhydrous 2 g Cu ₁ Jn- Calcium sulfate sulfate 76 ig 100 g anhydrous 3 g nickel Calcium sulfai bromide 76 Ver same - - 0

Example 2

Example 1 was repeated using a solution of an adduct consisting of triethylenediamine-melhanol-carbonyl sulfide in methanol, this solution having been prepared from 102 g of triethylenediamine, 300 cm ^{3 of} methanol and 60 g of carbonyl sulfide. The water-absorbing agents and oxidizing agents used in the various experiments and the yield of dimethyl carbonate in % of the theoretical value are shown in Table M below.

1-azabicyclo ^ 2,2,2) octane, methanol and carbonyl sulfide was used. The yield was similar to that of Examples 1 and 2.

Example 4

The procedure of Example 3 was carried out using an adduct of 1-azabicyclo-P ^ U-octane, methanol and carbonyl sulfide. It mostly similar results could be achieved ίο.

Example 5

The solution of an adduct of trimelhylamine. Ethanol and carbonyl sulfide were 200 g of water free calcium sulfate added. The solution was then oxidized for 24 hours at 25 ° C. and an excess oxygen pressure of 5.25 kg / cm ² in an autoclave with a stirrer. After the oxidation the solution was filtered so that the solid Besland parts have been separated. Then it was fractionated distilled and recovered the diethyl carbonate. The yield of diethyl carbonate was approximately 25 "., of the theoretical value.

In a similar experiment, about 2 g of cobalt

chloride used in place of the 200 g calcium sulfate. The yield of diethyl carbonate was about 70% of the theoretical value after oxidation of only one hour duration.

Example 6

table B e i s ρ ΊΙ Oxidation
iTii f IfI el 3 yield Mill ICI in% of
theo attempt water
absorbent retic medium Worth 25th 2a 200 g anhydrous . Sodium sulfate 35 2 B 200 g anhydrous 2 g CoCl ₂ Calcium sulfate 75 2c 200 g anhydrous 2 g CoCl ₁ , Calcium sulfate 300 g attapul 75 2d gitton 35 2e - 3 g cupri sulfate 75 2f - 5 g nickel bromide 75 2g - 0 Ver - same

The procedure of Example 2 was carried out in the same manner and the same number of tests, with the difference that an adduct was made from To the solution of an adduct of triethylamine, n-propanol and carbonyl sulfide were added 200 g of calcium sulfate (in order to absorb the water). To- the solution was then oxidized at 25 ° C. and an ^{excess oxygen pressure of 5.25 kg / cm 2} in an autoclave with a stirrer for a period of 24 hours. After the oxidation, the solution was filtered so that the solid components were removed.

Fractional distillation was then carried out to recover the di-n-propyl carbonate. The yield of di-n-propyl carbonate was about 15 "of the theoretical value, in a similar experiment, 2 g of Cupri chloride (as an oxidizing agent) instead of the 200 g Calcium sulfate (used as an absorbent for the water). The yield of di-n-propyl carbonate was after an oxidation time of only one hour approximately 70 "" of the theoretical value.

Example 7

The solution of an adduct of trimethylamine, isopropanol and carbonyl sulfide was 200 g of CaI- Calcium sulfate (to absorb the water) added. The solution was then oxidized at 25 ° C. and an overpressure of 5.25 kg / cm ² in an autoclave with a stirrer over the course of 24 hours. After the oxidation, the solution became filtered for the purpose of separating off the solid constituents and then fractionally distilled to obtain the diisopropyl carbonate. The yield was approximate 10% of the theoretical value.

In a similar experiment about 2g

Cobalt nitrate (as an oxidizing agent) is used in place of the 200 g calcium sulfate (to absorb the water). The diisopropyl carbonate bulge was approximately 50% of the theoretical value.

Example 8

Dimethyl carbonate was prepared by first dissolving 180 g of trimethylansine and 67 g of cup trichloride in 300 cm ^{3 of} methanol. The resulting amine-alcohol-cupric chloride solution was then about 5 minutes at approximately 25 ° C with carbonyl sulphate gas in an autoclave with a stirrer at a

Overpressure of 3.5 kg / cm * brought into contact until ISg carbonyl sulfide added to the mixture had been. The mixture was then stirred for a further hour at 25 ° C. The resulting mixture was fractionated distilled (under vacuum). The yield was 90% dimethyl carbonate. The oxidation when using of cuprichloride can be characterized in the following way:

CH ₈ O - C - S (CH,), NH + 2CuCl, + CH ₁ OH -> - CH ₃ O - C - OCH, + 2CuCl + (CHj) ₁ N + 2 HCl + S

In a similar experiment, 65 g of cobalt chloride, CoCl _{s, were} used instead of 67 g of cupric chloride. The yield of dimethyl carbonate was the same.

The method according to the invention thus creates a simple, relatively safe and fast and thus economical process for the production of dialkyl carbonates, from ammonium compounds of Carbonated half-esters. In the case of COS-containing adducts, the desired dialkyl carbonates can, according to the invention, be achieved by an oxidation at lower Temperature can be obtained. In addition, the COS-containing adducts are easy to convert into various carbon-containing end products. The reagents are not applied with the exception of the carbonyl sulfide and the alkanol for the representation the dialkyl carbonates or the metallic derivatives of the alkyl carbonates. The tertiary amine can always from the solution or dispersion according to the

ao final treatment in such a form are recovered that it can be used again according to the invention.

As can be seen from the examples given, oxidation is an effective concentration

as an absorbent for the water or an oxidizing agent of the type described to obtain a good yield from the solution or the dispersion with the adduct is required. If desired, the solution or dispersion can be both an oxidizing agent ak also contain an absorbent for water.

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Claims (1)

Amine and an alfrotjol at a temperature of Claim: · 0 to SO 'C. Fuhii-n & ii-aiese reaction with alcohol a solution or di-process is obtained in excess for the production of dialkylcarbospersion of the adduct in alcohol, which one immediately eats oxidize from 'an ammonium compound of a 5 bar by the method of the invention Carbonic acid half-ester, thereby gekenn- can, with dialkyl carbonate formed and thereby draws that an adduct is released from a water, free sulfur and tertiary anvn tertiary amine, an alcohol and carbonyl sulfide. For separating off the diacyl carbonate formed in an excess of alcohol and in counter- the solution is filtered and then distilled, wart of a water-absorbing agent and / or io When filtering, the precipitated free sulfur of an oxidizing agent at a temperature of and the optionally used w * · absurd at most MK) "C" oxidized. · .- * .bearing agents separated. When distilling, the * Alcohol separated from the dialkyl carbonate formed. Suitable for the method according to the invention 15 alcohols are, for example, methanol, ethanol, iso- propanol and propanol. The alcohol should not contain more than three carbon atoms. The carbonyl sulfide-containing Adducts produced during the procedure according to the The invention relates to a process for preparing the invention in the presence of excess alcohol are oxidized by dialkyl carbonates from an ammonium compound, obtained from the predung in excess of a carbonic acid half-ester. existing alcohol an alkoxy group to form de * It is already known (Römpp, »Chemie-Lexi-Dialkylcarbonats. kon «, 5th edition [1962], Volume II, Column 2644) that the oxidation, which leads to the formation of the dialkyl carbon Diethyl carbonate leads to prolonged exposure to phosgene, is usually under predominantly water on ethyl alcohol! arises. This known process under free conditions and using water to produce a dialkyl carbonate is, however, undertaken free of charge starting materials, although relatively expensive, since phosgene is expensive and this is not absolutely necessary. The oxidation is also extremely poisonous. can be carried out under predominantly anhydrous as well as under aqueous conditions in the presence of a technical and economical process for the production of oxidizing agent,
of dialkyl carbonates. The oxidation takes place at a temperature of This object is achieved by a process that does not exceed 100 ° C, so that no dialkyl carbonates are produced from an ammonium-borne amounts of carbonyl sulfide gas by thermal compound of a carbonic acid half-ester, which is characterized according to the invention by the decomposition of the adduct in the course of the oxidation is that one would be released, tine such decomposition would have a detrimental effect on an adduct of a tertiary amine, an alcohol, the final yield of the desired dialk> ca sound carbonyl sulfide in an excess of the alcohol. The temperature! erei: h and in the presence of a water-absorbing agent for the oxidation is between about 0 and 100 ^° C, and / or an oxidizing agent at a temperature preferably between about 0 and 50 ° C. Oxidizes at a temperature of at most 100 ° C. 40 temperatures below OC is the reaction speed That in the method according to the invention as low. The adduct used as a starting material is obtained by the oxidation can be shown as follows Implementation of carbonyl sulfide with a tertiary will be: