DE2113335A1 - Process for the preparation of solutions containing acetylene which can be used for the synthesis of alkynols and processes for the synthesis of alkynols using these solutions - Google Patents

Description

Process for the preparation of acetylene-containing solutions useful for alkynol synthesis and processes for alkynol synthesis using these solutions

The invention relates to a process for the preparation of solutions containing acetylene which are useful for the synthesis of alkynols, and also relates to a process for the synthesis of the alkynols in which these solutions are used.

Eb processes for the catalytic production of alkynols, starting from a ketone and acetylene, in the presence of alkali catalysts (alkaline catalysts) and a solvent, for example liquid ammonia, are known.

In the known processes, essentially pure acetylene must be fed; this not only entails high costs, since the pure acetylene is not available at high pressure from stability rounds, but there are also costs and special artifacts required to get the acetylene on the

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to bring the pressure necessary for alkynol synthesis.

According to the invention, a process for the synthesis of the alkynols is now to be provided proposed where a charge starting from a mixture of acetylene and others cheap and easy to be handled gases, can be used.

.Sin another object of the invention is in a / experienced for To see the production of mixtures containing acetylene, which can be used for the production of alkynols.

Another object of the invention is quantitative recovery of acetylene from gaseous mixtures containing them, being a gaseous essentially free of acetylene Electricity and an acetylene solution obtained for the Alkynolsynthese are useful.

These and other objects are achieved according to the invention by treating the gas containing AzeVaylen in an absorption column with a ketone, preferably an acetone, and thus obtaining essentially the entire amount of ethylene as the top product and a solution of acetyl in ketone as the bottom product; subjecting the solution thus obtained to a stripping operation with ammonia to obtain an overhead fraction which contains essentially all of the amount of acetylene and the other components present in the feed, possibly absorbed in the first stage of the process, together with the ammonia fed; that ^f the! b erkopf product, after condensation and optionally purifying ,, the alkynol synthesis together with a ketone and an alkali catalyst feeds · in that the alkynol then obtained separated from ";; and that the ammonia which Keaktionslösuriüsißj the , ttel is, as well as the nicely converted gases in the cycle of the absorption process, · returns; »

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Jas method according to the invention is used to make ammonia solutions or ammonia-containing solutions, hereinafter referred to as "ammonia solutions" for short, of acetylene to be obtained, with one starts from gaseous mixtures, which this together with other hydrocarbons, such as kethane, ethylene, ethane, propylene, Propane and the like, or other gases such as hydrogen, nitrogen and the like.

As is well known, acetylene occurs in very variable quantities as the main product, Coproduct or by-product in many gaseous fractions of petroleum, petrochemical or chemical origin.

These fractions can be cracked by cracking, steam cracking, arc methods, Teilverbrenmmgs- or other known methods obtained.

The method according to the invention is advantageously also suitable there where the mixture already contains a high percentage of acetylene, as many are related to the acetylene compression Problems disappear.

Preferably - but without being restricted to this - can the inventive hatred to absorb the in by Crude ethylene streams produced by hydrocarbon steam cracking J holding acetylene can be used.

It is a known fact that one of the more industrially interesting Process for making the ethylene is steam cracking of hydrocarbon feeds. That by means of steam cracking The raw ethylene produced always contains acetylene as a by-product and the amounts of acetylene are directly proportional to the Strict working conditions.

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In general, the proportion of acetylene is by 3ampfkracken (steam cracking) produced raw ethylene in the range of 1 to 10%.

These amounts of acetylene are by conventional means, in particular at low concentrations, it cannot be used economically for the production of pure acetylene and therefore becomes a purification of the ethylene by means of a selective hydrogenation of acetylene carried out-

This goal is associated with very high .kosten and the amount of acetylene is therefore easily limited to low values * with limitation of hardness or severity, in steam cracking, also taking into account the ethylene yield.

By the method according to the invention it is possible that in gaseous streams of acetylene present even at low concentrations for the production of alkynols, e.g. B. Ilethylbutynol, to take advantage of.

According to the invention it is thus possible, in the special case of the gaseous streams generated by steam cracking, to do this steam cracking to be carried out under more suitable working conditions.

It is a known fact that also the ethylene yields are directly proportional to the severity or harshness of the working conditions.

The process according to the invention makes it possible to obtain a raw ethylene stream which has been generated by both Ethylene-free ethylene as well as an acetylene solution useful for alkynol synthesis was cracked. One of the invention Measure internal advantage is that, since the raw ethylene streams obtained by steam cracking already

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are at high pressure, the quantities of acetone and / or the thermal cooling levels necessary for absorption are considerably reduced

One of the characteristic aspects according to the invention is in seeing that the presence of the non-acetylenic hydrocarbons in the mixture intended for the reaction, the course of the ethynylation reaction does not play a significant role modified.

These non-Äthylenkohlenwasserstoffe remain in the reaction product A unchanged and can be easily removed therefrom.

This makes it possible in terms of absorption selectivity Optimized working conditions do not need to be applied, as there are no special unit requirements for the supplied acetylene are set up.

The process of acetylene absorption according to the invention is carried out at pressures and temperatures that are independent of one another, combined with the need to keep the acetylene in the stability field in every stage and to ensure the desired acetylene recovery. %

According to the invention, temperatures are preferably in the range

from -40 ⁰ G to * 20 ° 0 and at pressures between 2 kg / cm ² bie

ρ
40 kg / cm worked.

Similarly, the ratios between the absorbent acetone and the treated acetone depend on the conditions mentioned and on the acetylene recovery desired, which is preferably between 15/1 and 1.50/1 parts by weight. Jcr Il he feripp process is preferably in a vaporization

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carried out at a pressure of 1 to 20 kg / cm, wherein Heat is supplied to the bottom of the column and ammonia is introduced into it, so that the overhead product of the preceding Process absorbed gases are obtained together with the introduced ammonia, preferably already at the acetylene / ammonia ratio, which is necessary for the correct functioning of the alkynol synthesis.

The procedure is such that acetone is obtained as the bottom product that is essentially free of volatile compounds.

The process of alkynol synthesis, especially methylbutynolsy . .:?. ese, is carried out according to the invention by the Lets acetylene react with a ketone in an ammonia solution and in the presence of alkali catalysts.

The possible presence of other grasses absorbed together with the acetylene did not show any significant effect on the Course of the synthesis reaction.

The presence of hydrocarbon gases or gases less polar than the acetylene in the absorbent Mixture does not lead to any disadvantage if these components do not react with the acetone under absorption conditions. Venn these compounds are dissolved in considerable proportions in acetone, they should not form compounds or complexes with Ammonia under the conditions of alkynol stripping ens and lead to synthesis.

The conditions of the methylbutynol synthesis he eaktion according to the invention are the following:

The synthesis temperature ranges from -40 ° C to +50 ⁰ C, preferably between -10 ° C and - - 30 ⁰ C?; the synthesis pressure is such that the reaction mixture is in

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liquid state, and the acetylene is in the stability field; preferably it is between 1 and 30 kg / cmj the i-molar ratios are between acetylene and ammonia in the range from 3/7 to 3/30;

the color ratios between acetylene and acetone are in Range from 1.5 / 1 to 10/1;

the solar ratios between the catalytic alkalines Compound or the alkali compound (alkaline compound) and the ketone are in the range from 0.005 / 1 to 0.1 / 1.

The invention will now be explained in more detail with reference to the accompanying drawings, in which the figures show embodiments illustrate for the process flow; Fig. 1 shows a first embodiment; FIG. 2 is a variant of that shown in FIG. 1 Flow diagram; FIG. 3 shows an embodiment for a special case and FIG. 4 shows a flow diagram according to a further development of FIG.

-> The following explanation is intended to simplify matters on the treatment of gaseous streams of ethylene and azethylene relate.

Obviously, the same flow sheets are also valid for other gaseous mixtures containing acetylene.

Ethylene is in fact among the hydrocarbon gases with ™ 1 to 3 carbon atoms that which has a polarity closely adjacent to that of the azethylene; put it So there are greater difficulties in separating them by absorption.

The other possible components were less difficult » separation and lower costs.

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In Pig. 1, a gaseous stream _t, which, as said, consists of ethylene and acetylene, is introduced through 1 into the absorption column 2, into which the gaseous return streams are introduced via lines 3 and 4.

The absorbent recycled from the stripping process Acetone is supplied via line J? introduced while fresh acetone is fed via line 6 in an amount sufficient for the synthesis reaction.

A current is withdrawn through line 7, which is essentially consists of ethylene with a small amount of acetone, corresponding to the saturation under absorption conditions. 3 very well known and therefore procedures not indicated here in the scheme this acetone is removed and recovered.

From the bottom of the absorption column 2, a solution of acetylene in acetone is discharged via line 8; this solution contains essentially the entire amount of acetylene supplied over 1.

The absorption process requires cooling to condense the acetylene and the other gases dissolved in stream 8; in the This cooling is done by changing the sensible heat of the solvent. The solution obtained is Introduced into the Exhauster column 9, which via line 10 a. Ammonia stream is supplied, this ammonia as Stripper agent works for the gases dissolved in acetone.

A boiling or boiling-up apparatus 11 supplies the equipment to be carried out Process necessary heat so that in the flow of volatile substances leaving the column bottom via line 12 Products is obtained essentially free acetone. The top of the head product, which is discharged through the line 13,

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BATHROOM QRJGINAL

consists of the gases dissolved during the absorption process of the column 2 and the ammonia introduced via 10.

This stream is condensed in a partial condenser 14 to yield ethyl an ammonia solution of Az ens and ethylene and a non-condensed fraction obtained consists predominantly au "ethylene, this fraction to the column 2 üb"? the line 3 is returned.

The ammonia solution of the AzethyleneO and ethylene is then passed to the reaction zone 16 via the line 1JjJ. The catalyst ' j

is carried out via line 17. ™

From the bottom of the column 9 is discharged, the necessary for the reaction of acetone over lines 12 and 18, wherein said acetone to the reaction zone 16 after cooling in the Wärmeauetau-. shear 19 and 20 is fed.

Generally speaking, the acetone used in the synthesis can be kept completely separate from the acetone used in the absorption; however, the integration of the absorption acetone into the acetone used in the synthesis improves the process considerably.

The reaction product is obtained from the reaction zone 16 via line 21. This product consists of methylbutynol, ammonia, unreacted acetylene, unreacted acetone and the ethylene, which has remained unchanged. This mixture is allowed to expand in a separating column 22, from the top of which vapors consisting of ethylene, acetylene and ammonia are discharged via line 23.

These vapors are fed into the partial condenser 24, which is a Generates condensate, which mainly consists of ammonia,

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10 98 h 1/1 96 1

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which to the column 9 via line 10 after previous evaporation is recycled in 19. The non-condensed, leil consisting primarily of ethylene and acetylene is recycled to column 2 via line 4.

From the bottom of the column 22, a line 25 is made up of methylbutynol, unreacted acetone and traces of ammonia existing electricity discharged. This mixture is then fed to the second separating column 26, and via the line 27 receives an overhead product which essentially consists of Consists of acetone and ammonia, the product being led to column 9 rüv ^ £; one also obtains a soil product which consists of the methylbutynol produced, which is discharged via line 28.

Fig. 2 shows a variant of the flow diagram according to Fig. Λ, According to Pig. 2, the vapors obtained from column 9 are fed to column 29, v / o the acetylene purification is completed.

To facilitate the task of the stream 30, for example In order to limit both its throughput and its heat level, part of the ammonia solution is obtained via line 15 Acethylene cooled in the heat exchanger 32 and reintroduced via line 35 at.

Fig. 3 shows a simplified flow diagram in the opposite Certain changes have been made to the scheme of FIG.

The vapors obtained from the top of the column 9 are total fed to the reaction zone 16 after prior condensation at 14 ·> The overhead product of the column 26 is in the circuit

109841/1961

returned in the vapor phase to column 9 via line 27.

The scheme according to FIG. 3 is particularly suitable when the hydrocarbons dissolved in the acetone of stream 8 are already one have a high proportion of acetylene; in this case is another Cleaning step due to partial condensation not required.

The return of ethylene for absorption is accomplished via line 4. If finally the solution obtained from the absorption consists essentially only of acetone and acetylene, the scheme according to FIG. 5 is further simplified according to "the flow diagram of FIG To provide the absorption process necessary cooling without having to accept very high throughputs and heat levels at 5.

The small amount of light non-azethylene components that as impurities are present in stream 8 can be removed by applying these compounds via line 36.

In summary, it can be said of the examples that the flow diagram of FIG Shipments with a low proportion of acetylene must be treated, in which the proportion of ethylene is not very high.

Fig. 2, however, is typical of the case of an ethylene-acetylene mixture with a low proportion of acetylene.

If the proportion of acetylene is higher, the scheme according to FIG. 3 is to prefer. The flow diagram according to Fig. 4- is used with advantage when the acetylene is free of diluents,

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which have considerable solubility in acetone under absorption conditions.

Patent claims:

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Claims (12)

Patent claims 1. Process for the production of acetylene solutions, which at the alkynol synthesis can be used, characterized in that that a) a gaseous) mixture containing acetylene with ketones is treated; b) the ketone solution is stripped with ammonia ·, and c) the alkynol synthesis zone, the gases absorbed in a), the ' ammonia alkali catalyst introduced for stripping are fed ammonia introduced for stripping, as well as a ketone and the ^ 2. The method according to claim 1, characterized in that the gaseous mixture consisting essentially of acetylene and Ethylene consists. 3. The method according to claim 1, characterized in that the ketone is a cetone. 4. The method according to any one of the preceding claims, characterized in that the acetone absorption of the acetylene contained in the gaseous mixture at temperatures in the range from -4O ⁰ C to 4-20 ⁰ O is carried out. 5. The method according to any one of the preceding claims, characterized characterized in that the acetone absorption of the acetylene contained in the gaseous mixture at pressures in the range between 2 and 40 kg / cm is carried out. 6. The method according to any one of the preceding claims, characterized in that the weight ratio between ab- - -14 1 η η a u / 1 π sorbing acetone and treated methylene is preferably in the range between 15/1 to ~) 5Q / i , 7 · Method according to one of the preceding claims, characterized characterized that the £> tripper process in an evaporator column preferably at a pressure in the range between 1 to ρ
20 kg / cm is carried out. 8- Process for alkynol synthesis, characterized in that a) the gaseous, acetylene-containing mixture with a Ke-A sound is absorbed; b) the mixture obtained under a) is stripped with ammonia; c) the alcohol synthesis zone containing the gaseous acetylene gaseous ammonia mixtures together with a Ketone and an alkali catalyst are fed; and 4) the obtained alkynol is recovered. 9. The method according to claim 1, characterized in that the alkynol synthesis process at a temperature in the range from -40 ° G to 4 50 ⁰ G, preferably from + 10 ⁰ G to + 50 ⁰ O, carried out φ becomes. 10. The method according to claim 1, characterized in that the Synthesis process is carried out at a pressure in the range between 1 and 30 kg / cm, with the reaction mixture in the liquid State and the acetylene is in the stability field. 11. The method according to claim 1, characterized in that when _t synthesis process the molar ratios between acetylene 1098A1 / 1961 and ammonia in the range between 5/7 and 3/30. 12. The method according to claim 1, characterized in that the synthesis process, the molar ratios between acetylene and the ketone range between 1.5 / 1 to 10/1. ■ * 3 · Method according to claim 1, characterized in that during the synthesis process, the molar ratios between the alkali metal compound used as a liatalysator and the ketone in the range between 0.005 / 1 to Ö, i. / 1. 14 ·. Process for the production of ethylene-free ethylene and ^ ammonia-containing solutions of acetylene, which can be used for " the alkynol synthesis, starting from ethylene and acetylene, characterized in that a) the gaseous mixture of ethylene and acetylene in countercurrent is treated with acetone, a solution of the acetone in acetone and an im substantially acetylene-free ethylene stream is formed; b) the acetylene is removed by stripping with ammonia; and c "i züge- the ammonia solution of the Azethylens the synthesis zone is ä passes. 108841/1981