CS212944B1 - Method of making the technical diethylether - Google Patents

Description

Acetaldehyde, ethanol and water are the main impurities that the diethyl ether concentrate obtained by one of these processes contains. While ethanol can be separated relatively easily from diethyl ether by efficient distillation, this process is not sufficient for acetaldehyde and water, since both form azeotropic mixtures with diethyl ether.

Refining diethyl ether from acetaldehyde can be accomplished by further extractive distillation with water followed by scrubbing with a chemically active reagent. Removal of water, which dissolves in the ether at a concentration of about 1.3% by weight, is possible by percolation of the ether with a layer of solid NaOH, molecular sieves, etc. The described classical method of refining diethyl ether is very complicated and leads to waste and polluted water.

It has also been found that technical diethyl ether from the products of direct hydration of ethylene can be made from a diethyl ether concentrate separated by distillation from ethanol and refined from the use of hydrogen and an active catalyst whose active component is supported nickel or active nickel alone.

A new, more efficient process has now been found, comprising concentrating diethyl ether with a content of at least 70% by weight. the diethyl ether is refined in the presence of an active catalyst containing nickel, preferably Raney nickel, at a temperature of not more than 160 ° C, preferably 60 to 120 ° C and a pressure of not more than 3.0 MPa, preferably 0.4 and 2.0 MPa, and in the subsequent redistillation step, it is divided into technical diethyl ether and ethanol concentrate, whereby in this distillation step, a diethyl ether with reduced water content is withdrawn as a lateral withdrawal between the feed point and the distillate collection point.

The eventual decrease in catalyst activity can be advantageously restored by adding alkali to the diethyl ether concentrate stream entering the hydrogenation. The hydrotreating product is separated into the technical diethyl ether and ethanol concentrate in the subsequent redistillation step. The distillate - technical diethyl ether - is the final product meeting commercial quality standards, while the ethanol concentrate from the bottom of the distillation column returns to the distillation of the spirits condensate. With this arrangement, the possible addition of alkali to the hydrogenation reactor does not interfere with the further processing of the product.

It has also been found that dewatering of diethyl ether can be achieved by suitable redistillation arrangements such that the final product is withdrawn as a side withdrawal between the feed point and the overhead distillation point. This yields a technical diethyl ether with reduced water content and no further drying is necessary. In the case of the removal of a side-stream from the hydrogenated ether redistillation stage, the overhead distillate of this stage may be returned at least partially to the distillation stage of the diethyl ether concentrate preparation prior to its hydrotreating.

An arrangement of an exemplary technological production line for the technical diethyl ether according to the invention is shown in FIG. 1. The production of diethyl ether from the concentrate obtained is described.

212 944 in the production of synthetic ethanol without the inclusion of extractive distillation, but also the production of diethyl ether according to the invention can be applied if this extractive distillation is used for ethanol refining. The technological diethyl ether production line in said configuration comprises the following steps:

- rectification of the product of direct hydration of ethylene in column 21,

- etherification of synthetic ethanol in column 22,

- hydrotreating the diethyl ether concentrate in the reactor 31.

- redistillation of the hydrogenated ether in column 23.

The reaction product of the direct hydration of ethylene is fed to the process line via a line

Synthetic ethanol containing diethyl ether is discharged as distillate of the rectification column 21 via line 2, the return flow is returned to the top of the column via line 5 and the waste water is discharged from the bottom via line 6. Synthetic ether-containing ethanol was sprayed ns odéterovácí column 22 to feed is optionally added recycled moist diethyl ether of hydrogenated redistillation duct 17 »odéterovací column as distillate is withdrawn via line £ concentrate ether ^ns head of the column reflux return line 6, the rest is destilačnlm Synthetic ether, ether, 2 '

The diethyl ether concentrate is fed to a reactor 31 where it is subjected to hydrogen refining using hydrogen supplied via line 8. The refined diethyl ether is fed via line 2 to an ether redistillation column 23 where the technical diethyl ether is distilled off from the distillation residue, i.e. ethanol concentrate, removed via line 13. distillate from the top of the column 23 is taken via line 10 a wet diethylether ^{»on the} head of the column reflux return line 11. the side takeoff of the column taken redestilsční ether with a reduced content of water pipes 12. the moist diethyl ether, removed as the distillate can be rerun column 23rd in order to increase the yield of the reduced water product, return via line 13 either to the feed of the de-ether column 22 (line 17) or to the rectification column 21 (line 14) where the remainder of the redistillation column is returned via line 16.

Example

On the 7th theoretical floor of the hydrogenated diethyl ether redistillation column, a mixture comprising:

91.09% wt. diethyl ether,

7.92% wt. ethanol,

0.99 wt% water.

The column has 11 theoretical plates and operates at a reflux ratio of 1.5. The distillate of the column contains:

98.30% wt. diethyl ether,

0.73% wt. ethanol,

0,97 $ w / w water.

212 944

The ratio of the liquid and steam molar flow rates on the trays above the feed into the column is 0.6, the working pressure is 0.2 MPa.

The distillation according to the invention is performed while maintaining the same ratio of liquid to steam molar flow rates on the trays of the column between the feed and the side product liquid collection point. The column has 11 theoretical trays, feed of the same composition is fed to the 9th floor, and the side draw in the liquid phase is withdrawn at the outlet of the 2nd theoretical floor.

The ratio of the mass flow of the distillate to the side outlet is 5: 4. Both products have the following composition:

distillate lateral exhaust diethyl ether 99.22% wt. 98.59% wt. ethanol 0.36. % wt. 0.98% wt. water 1.42% wt. 0.43% wt.

OBJECT OF THE INVENTION

Claims (3)

Process for the production of technical diethyl ether from products of direct hydration of ethylene, wherein the diethyl ether concentrate separated by distillation from ethanol ε containing at least 70% by weight of ethyl ether. diethyl ether, refined by hydrogenation using hydrogen and an active catalyst, preferably a catalyst having the active component supported and / or active nickel alone, at a temperature of not more than 160 ° C and a pressure of not more than 3.0 MPa, characterized in that the product The hydrogenation refining in the subsequent redistillation step is divided into technical diethyl ether and ethanol concentrate, whereby in this distillation step a diethyl ether with reduced water content is withdrawn as a lateral withdrawal between the feed point and the distillate collection point. 2. Process according to claim 1, characterized in that, during the removal of the side-stream from the hydrogenated ether redistillation stage, the distillate of this stage is partially returned to the distillation stages of the diethyl ether concentrate preparation prior to its hydrotreating. 3. Process according to claim 1, characterized in that alkali is metered into the feed stream of the diethyl ether entering the hydrogenation.