DE1172677B - Process for the production of pure, alcohol- and water-free organic liquids from alcohol- and / or water-containing liquid mixtures - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school KL: C 07 b

German class: 12 ο-27

Number: 1172 677

File number: W 29189 IV b / 12 ο

Filing date: December 30, 1960

Opening day: June 25, 1964

The use of alcohol-free and anhydrous liquids is necessary for many reactions in order to avoid undesired Avoid side reactions. Alcohol-containing and / or water-containing mixtures are usually used separated with other organic liquids by distillation. However, this path is only then practicable if the boiling point of the alcohol and / or water is lower than the boiling point of the one to be cleaned Connection are sufficiently different. In most cases a complete separation succeeds not. Neither can azeotropic alcohol- and / or water-containing mixtures by simple distillation be separated.

It has already been proposed to use the mixture to remove lower alcohols from mixtures Shake out with concentrated, aqueous salt or alkali hydroxide solutions. Apart from this, The result of such a treatment is that the alcohol cannot be completely removed in this way a water-containing product, from which the water only goes through a further azeotropic distillation or has to be removed again by desiccant. This procedure is cumbersome and inconvenient tied together.

For the separation of e.g. an azeotropic mixture of methanol and methylal, it has also been suggested that to distill the mixture extractively with the addition of water. One gets in this way Although a methanol-free methylal, it brings water back into the end product, which only takes place in a second Stage must be removed either by desiccant or by a further azeotropic distillation. There are thus in principle the same disadvantages as with the earlier methods.

A process has now been found for obtaining pure alcohol- and water-free organic liquids from alcohol- and / or water-containing liquid mixtures, wherein the pure alcohol- and water-free organic liquid is distilled off over the top of the extraction column and the alcohol and / or as bottom product receives water-containing extractants. The process is characterized in that the extractant used is a compound of the formula RCONR ' ₂ , in which R and R' denote hydrogen atoms or an alkyl radical which is optionally substituted by hydroxyl or amino groups.

Compounds which can be used with advantage as extraction agents in the process according to the invention are carboxylic acid dialkylamides, such as dimethylformamide, dimethylacetamide, dimethylpropionamide, diethylformamide, diethyl processes for obtaining pure,
alcohol-free and anhydrous organic
Liquids made from mixtures of liquids containing alcohol and / or water

Applicant:

Wacker-Chemie G. mb H.,
Munich 22, Prinzregentenstr. 20th

Named as inventor:
Dr. Eduard Enk,
_e Dr. Fritz Knörr,

Dr. Hellmuth Spes, Burghausen (Obb.)

acetamide, glycolic acid dialkylamides, lactic acid dialkylamides, amino acid dialkylamides, or the corresponding Carboxylic acid monoalkylamides. Likewise, carboxamides, which are carried out on nitrogen Hydroxy or amino groups carry substituted alkyl radicals, can be used. Possibly Mixtures of the extractants mentioned can also be used.

The process can generally be used for alcohol- and water-containing azeotropes and non-azeotropes Mixtures in which the boiling points of the components of the mixture are similar and the therefore cannot be separated by distillation, use. For example, in this way separate: alcoholic and / or water-containing acetals, esters, ketones, amines, ethers, cyclic ethers, aromatics and halogenated hydrocarbons.

The method can e.g. B. be carried out in such a way that the mixture to be purified is _{continuously added to the lower part of a fractionating column and the compound R — CONR '2 is added to} the upper part. If the ratio of mixture to extractant can easily be determined by a preliminary test, the pure, alcohol-free and anhydrous organic liquid can be obtained at the top of the column and the alcohol- and / or water-containing compound RCONR ' ₂ can be obtained from the bottom of the column. The processing of the bottom effluent into the components takes place by discontinuous or continuous stripping off the lower-boiling constituents. The extractant recovered in this way can be fed back to the extraction column.

409 627/408

It is already a process for separating ester-alcohol mixtures by extractive distillation known with ethylene glycol (German Auslegeschrift 1088 040), the ester being a higher one Boiling point than the alcohol has. In contrast, the method according to the invention can not only be used in Ester-alcohol mixtures, but in the same way also for example with alcohol and / or hydrous acetals, ketones, amines, ethers, aromatic compounds and halogenated hydrocarbons use. This special property of the extractants according to the invention was off its structure cannot be derived.

Next is a process for separating ester-alcohol mixtures by using extractive distillation Dicarboxylic acid esters, hydrocarbons, ketones or keto esters described (German Auslegeschrift 1066 584). In this case, however, the alcohol and not the ester is obtained as a distillate.

example 1

Into a column equipped with a distillation head, the flask of which has a continuous overflow owns, a mixture of 94.7% methylal and 5.3% methanol with a temperature in the lower third of 35 ° C and introduced dimethylformamide at a temperature of 60 ° C in the upper third. The volume ratio of the liquids introduced is 3: 1. With an hourly addition of 258 g of the methylal-methanol mixture and 95 g of dimethylformamide are on average hourly 241 g of pure methylal withdrawn at the top of the column and 109 g of bottom effluent, which can be separated into its components by distillation. That received back in this way Dimethylformamide can be fed back into the column. The yields are almost quantitative.

In the same way and with the same success, dimethylacetamide can also be used in place of dimethylformamide can be applied.

Example 2

The device described in Example 1 is, as described above, a mixture of 80% Methylal and 20% methanol and dimethylformamide in a volume ratio of 3: 1 are supplied. With an hourly addition of 258 g of the methylal-methanol mixture and 95 g of dimethylformamide an average of 212 g of pure methylal per hour at the top of the column and 139 g of bottom effluent obtained, which is worked up as in Example 1. The yields are almost quantitative.

In the same way and with the same success, diethylacetamide can also be used instead of dimethylformamide or diethylformamide can be used.

Example 3

A mixture of 60% methylal, 20% methanol and 20% water as well as dimethylformamide can be used as in Example 1, fed to the column in a volume ratio of about 3: 1. With an hourly addition of 274 g of the mixture and 95 g of dimethylformamide, an average of 162 g per hour is obtained Pure methanol and anhydrous methylal obtained at the top of the column and 203 g of bottom effluent. the Yields are almost quantitative.

In the same way and with the same success, glycolic acid diethylamide can also be used in place of dimethylformamide or lactic acid monoethylamide can be used.

Example 4

As in Example 1, the column will be a mixture of 97% methylal and 3% water as well Glykolsäurediethylamid supplied in a volume ratio of ίο 4: 1. With an hourly addition of 344 g of the mixture and 95 g of glycolic acid diethylamide are an average of 332 g of pure per hour Received methylal at the top of the column and 104 g of bottom effluent. The yields are almost quantitative.

In the same way and with the same success, dimethylformamide can also be used in place of glycolic acid diethylamide can be applied.

Example 5

As in Example 1, a mixture of 75% acetaldehyde ^{dimethylacetal and 25 u} / o methanol and diethylformamide in a volume ratio of about 1: 1 are fed to the column. With an hourly addition of 265 g of the mixture and 190 g of diethylformamide, an average of 168 g of pure acetaldehyde dimethylacetal per hour and 283 g of bottom effluent are obtained at the top of the column. The yields are almost quantitative.

In the same way and with the same success, dimethylformamide can also be used in place of diethylformamide or lactic acid monoethylamide can be used.

Example 6

A mixture of 80% acetaldehyde diethylacetal and 20% propanol and lactic acid monoethylamide are fed to the column at temperatures of 67 and 80 ° C. as in Example 1 in a volume ratio of about 2: 1. With an hourly addition of 374 g of the mixture and 190 g of lactic acid monoethylamide, an average of 275 g of pure acetaldehyde diethyl acetal per hour are obtained at the top of the column and 285 g of bottom effluent. Yields are nearly 10O ⁰ Zoig.

In the same way and with the same success, diethylacetamide can also be used instead of lactic acid monoethylamide or dimethylformamide can be used.

Example 7

A mixture of 45% dioxane and 55% propanol and diethylacetamide are the column as in Example 6 supplied in a volume ratio of about 2: 1. With an hourly addition of 350 g des The mixture and 170 g of diethylacetamide are on average 156 g of dioxane per hour at the top of the Column and 361 g of bottom effluent obtained. The yields are almost quantitative.

In the same way and with the same success, a dioxane-propanol mixture can also be replaced by a Mixture of methyl ethyl ketone and propanol are separated. Diethylacetamide can also be used be replaced by dimethylformamide or glycolic acid diethylamide.

Example 8

A mixture of 88% acetone and 12% methanol and diethylformamide are the column as in

Claims (1)

Example 1 received in a volume ratio of about 1: 1 inflow. The yields are almost given. With an hourly addition of 240 g of titative. Mixture and 290 g of diethylformamide are used in the same way and with the same success Average hourly 209 g of acetone at the top instead of the tetrahydrofuran-methanol mixture Column and 317 g of bottom drain obtained. The Aus 5 also yielded a mixture of thiophene and ethanol are almost quantitative. be separated. Diethylformamide can also be used In the same way and with the same success can be replaced by dimethylformamide,
Instead of the acetone-methanol mixture, a Be ^- 'el 13 Mixture of methyl acrylate and ethanol ge P be separated. The diethylformamide can also be replaced by dimethylformamide, a mixture of 55% ethyl sulfide and 45% allyl. Alcohol and dimethylformamide are fed to the column as in Example 1 in the volume ratio of Example 9 _about jj. With an hourly addition A mixture of 50% diethylamine and 50% of 270 g of the mixture and 270 g of dimethyl-methanol as well as lactic acid monoethylamide are 15 formamide are an average of 145 g per hour of the column as in Example 1 in the volume ratio of ethyl sulfide at the top of the column and 388 g of bottom of fed about 1: 1. Received with an hourly inflow. The yields are almost equivalent of 270 g of the mixture and 290 g of lactic acid titative. monoäthylamid are on average every hour in the same way and with the same success 132 g of diethylamine at the top of the column and 425 g of 20 instead of the ethyl sulfide-allyl alcohol mixture Received sump drain. The yields are almost also a mixture of ethyl propyl ether and ethanol quantitatively. be separated. Dimethylformamide can also be used Diethylacetamide can be substituted in the same way and with the same success,
instead of the diethylamine-methanol mixture also Beiso "1 14 a mixture of methyl borate and methanol separated 25 P will. Lactic acid monoethylamide, a mixture of 70% fluorobenzene and 30% iso- be replaced by dimethylformamide. propyl alcohol and dimethylformamide are the Column as in Example 1 in the volume ratio of Example 10 _{fed about} jj. With an hourly addition A mixture of 67.6% benzene and 32.4% 30 of 260 g of the mixture and 280 g of dimethyl ethanol as well as glycolic acid diethylamide, the formamide are an average of 177 g per hour Column as in Example 1 in the volume ratio of fluorobenzene at the top of the column and 359 g of bottom approx 1: 1 fed. With an hourly addition expiry received. The yields are almost quantitative 270 g of the mixture and 290 g of glycolic acid. diethylamide is an average of 180 g per hour 35 in the same way and with the same success Benzene at the top of the column and 375 g sump instead of the fluorobenzene-isopropyl alcohol drain obtain. The yields are almost quantitative, including a mixture of 2-bromopropane and titative. Methanol are separated. Likewise, the Di- In the same way and with the same success, methylformamide can be replaced by glycolic acid diethylamide instead of the benzene-ethanol mixture.
Mixture of ethoxytrimethylsilane or allyl formate Example 15 and ethanol are separated. It can also Glykolsäurediäthylamid by Dimethylformamid er The described in Example 1, but with are set. 10 Torr working device will be a _n . -I ₁₁ 45 mix of 80% formaldehyde dibutyl acetal and 20% Example 11 sec-octanol at 50 ° C and glycolic acid diethyl A mixture of 80% methyl acetate and 20% amide at 45 ° C. in a volume ratio of about 2: 1 methanol and diethylacetamide are fed to the co-. With an hourly addition of 135 g lonne as in Example 1 in a volume ratio of the acetal-alcohol mixture and 70 g of glycol, about 1: 1 is added. With an hourly addition of 50 acid diethylamide, an average of 260 g of the mixture and 290 g of diethylacetamide per hour, 101 g of formaldehyde dibutyl acetal at the top of the Kowerden, an average of 205 g of methyl acetate per hour and 102 g of bottom effluent are obtained, which is obtained through the top of the column and 342 g of bottom Keep vacuum distillation broken down into its components. The yields are almost quantitative. ^will · The yields are almost quantitative. In the same way and with the same success, milk, a mixture of methyl carbonate and allyl alcohol, can also be used in place of the methyl acetate-methanol mixture and in place of glycolic acid diethylamide, and milk, a mixture of methyl carbonate and allyl alcohol.
be separated. Diethylacetamide can also be used
be replaced by dimethylformamide. Claim: ^eis P ^he process for the production of pure, alcoholic A mixture of 50% tetrahydrofuran and 50% and anhydrous organic liquids Methanol and diethylformamide are the alcohol and / or water-containing liquids lonne as in Example 1 in the volume ratio of mixtures by extractive distillation, wherein fed about 1: 1. With an hourly addition, the alcohol-free and anhydrous organic of 260 g of the mixture and 285 g of diethylform liquid over the top of the extraction amide, an average of 125 g of tetracolumn per hour are distilled off and the bottom product is the hydrofuran at the top of the column and 415 g of sump alcohol and / or aqueous extraction agent 7 8 obtained, characterized in that ierte alkyl radicals with J to 3 carbon atoms one as extractant a compound of mean. Formula RCONRZ ₂ used, in which R and R 'are hydrogen atoms or, where appropriate, documents considered: substituted by hydroxy or amino groups. 5 Deutsche Auslegeschriften Nr. 1066 584, 1088 040. 409 627/408 6.64 © Bundesdruckerei Berlin