DE1132916B - Process and device for the reaction of acetylene with itself or with carbon monoxide and water - Google Patents

Description

Process and device for the reaction of acetylene with itself or with carbon monoxide and water It is known that acetylene after sufficient Dilution can be compressed to pressures at which without risk of decomposition the partial pressure of acetylene above the decomposition limit pressure of pure acetylene lies (German patent specification 1 028 563).

It is also known that using acetylene under pressure is relatively safe can be worked if the gas spaces are kept so small that in them no detonation can leak (W. stairs, chemistry and technology of acetylene pressure reactions, 1951, pp. 11 to 14 and 25 to 30).

There are from Reppe (chemistry and technology of acetylene pressure reactions, Verlag Chemie, 1951, p. 7 and f.) Investigations into the ignitability of acetylene depending on pressure and temperature as well as depending on the composition has been described in the case of mixtures of acetylene with other gases. Also the explosiveness of acetylene has been extensively investigated (Ullmann, »Encyclopadie der Technische Chemistry «, vol. 3, p. 43) as well as ignition limits and pressure behavior of the solutions (research report of the Ministry of Economic Affairs and Transport, North Rhine-Westphalia No. 206: Investigations on the processes involved in adding acetylene dissolved in acetone).

It is also known from German patent specification 1 028 563, Reacting acetylene to Cyclooctatretaen, the reaction with such a mixture from acetylene and an inert gas is carried out that the total pressure is indeed more than 75 ata, but is below the disintegration limit pressure of the total weight, and the total pressure is so high that the solubility of the acetylene in the liquid Phase remains below the ignition limit concentration. By diluting the acetylene a non-ignitable gas phase is accordingly obtained with an inert gas. So must z. B. a total pressure of 100 ata can be maintained if the acetylene partial pressure should be 20 to 22 ata in the system. The working pressure is therefore five times higher than the acetylene partial pressure, which is solely responsible for the reaction rate is.

In another known method (German patent specification 1 018396) the gas phase in the reactor can be avoided entirely. Work here saturators and Reactor at the same pressure, so the reaction temperature is limited; because the ratio of the solubility coefficient is allowed for the reactor and the The saturator temperature must not be greater than the ratio of the total pressure to the acetylene partial pressure. Otherwise, larger amounts of acetylene can outgas in the reactor. There are still Ver drive described in which the saturator and furnace under different working pressure stand. The concentration of the dissolved acetylene is still below the Ignition concentration of the liquid phase (German patent specification 1 029 369).

The working pressure in the reactor can always be chosen so that the Acetylene not outgassed. However, the last two procedures mentioned do not apply Instructions for how the reaction solution should be mixed. But this is in technical equipment, especially in reactions with a high degree of heat development, extremely important when achieving a good yield and holding back side reactions should be.

In the previously known method for the implementation of acetylene under Pressure in a solvent with either dissolved or suspended catalyst is used the acetylene is diluted and circulated, with the circulating gas circulating in the reaction system drives, or the amount of acetylene supplied is such that the acetylene in the Reaction furnace is consumed for the most part. A way of working is also possible without gas phase, in which the acetylene is supplied in dissolved form (German patent 1 018 396).

In any case, the acetylene concentrations are generally calculated in such a way that that they are below the ignition limit concentration lie with a Solution that is not in equilibrium with any gas phase, at around 100 liters of acetylene per liter of solvent.

When working with circulating gas, expensive high-pressure equipment is required be used. The other two procedures, where either the Acetylene for the most part consumed in the reaction furnace or worked without the gas phase on the other hand, it is difficult to thoroughly mix the reaction solution to achieve.

It has now been found that when reacting acetylene with itself or with carbon monoxide and water in the liquid phase in the presence of dissolved or suspended catalysts at temperatures up to about 4000 C below the ignition limit of the dissolved acetylene, which is in addition to that in the reaction consumed amount of acetylene is measured so that only small Acetylene gas spaces can form in the reaction vessel and the acetylene is gaseous either together with carbon monoxide and water at pressures up to 100 atmospheres or at the reaction with itself at pressures up to 20 atmospheres or in the dissolved state Pressing up to 100 atü introduces a good internal circulation in the reaction chamber System and thus sufficient mixing of the reaction solution is obtained, if the internal circulation of the reaction solution in the reaction vessel mainly through impulse emission one or more, relaxed in a circulation tube arranged in the reaction vessel, liquid jets containing a portion of the acetylene gas in dissolved form as well as by reaction gas additionally added from below into the circulation pipe will. The inlet is therefore introduced into the circulation pipe through a nozzle. Here it is not necessary to design the end of the circulation pipe as a collecting nozzle; a seamless, smooth pipe is sufficient.

The specified method now makes it possible in the Cyclooctatetraensynthese to work in the reactor with an acetylene gas phase, which is not with an inert gas is diluted. The gas phase is namely caused by the action of the liquid jet so finely distributed that the energy released in a gas bubble when it breaks down not enough for the next vesicles to pass through the surrounding fluid layer to ignite.

The ratio of the outer to the inner circumferential cross-section should be appropriate between 1 and 5, preferably between 1.5 and 3.5, the ratio of the diameters of circulating pipe and nozzle between 80 and 200. With a given inflow rate, select one expediently the dimensions so that the exit speed of the liquid jet is between S to 70 m / second, preferably between 20 to 60 m / second.

In general, some of the gas is in dissolved form with the feed introduced under pressure into the reaction vessel. But you can also use the entire amount of gas either in gaseous form in a separate feed pipe or in dissolved form from the inlet into the reaction vessel and select the pressure in the reaction vessel so that that no gas phase occurs in it under reaction conditions. If necessary, selects the pressure is so that only 0.1 to 3 percent by weight of the dissolved acetylene outgas.

A circulation pipe is arranged in the reaction vessel, its diameter about two tenths to seven Tenth of the inner diameter of the reaction vessel and in its lower opening one or more supply pipes for the to be relocated, open to pressurized substances. This creates an orbital movement in the reaction vessel sustained substances located in such a way that the substances in the circulation pipe upwards, in the outer annular space between the circulation pipe and the jacket of the reaction vessel move down. The same movement device results when the or the supply pipes in the space between the upper mouth of the circulation pipe and the jacket of the pressure vessel are arranged.

This movement can be reversed in that the feed pipe or pipes for the substances to be converted in the space between the lower opening of the Circulation tube and the jacket of the reaction vessel or in the upper opening of the Circulation pipe are arranged.

A scheme of the plant according to the invention is shown in the figure.

The solvent L is supplied via control valve 1, feed tank 2, pipeline 3, Valve 5 and pipe 6 from the circulation pump 7 via the pipe 8 through a The nozzle 9 is pressed into the circulation pipe 10 of the reaction vessel 11. Immediately before the The catalyst K is fed to the nozzle 9 in the line 12 of the pipeline 8, see above that solvent L and catalyst K combine and together through the nozzle 9 enter the reaction vessel 11.

The fresh gas F is, insofar as it is also necessary, on the Line 13, compressor 14, valve 15 and pipe 16 through the nozzle 17 is also blown into the circulation pipe 10. The valve 18 is closed. The amount of fresh gas is calculated so that, in addition to the sparkling gas, about 1 to 25 percent by volume gaseous through the attached to the top of the reaction vessel 11 Discharge valve 27 go.

The fresh gas can also be completely or partially dissolved in the solvent be placed in the reaction vessel. For this purpose, the valve 15 is partially closed and the valve 18 is opened. The fresh gas then goes through the valves 18, 19 and 20 and the pipeline 21 from below into the partially filled with solvent Saturator 22. The solvent L is here with the valve 5 closed by the The saturator pump 23 is pushed into the line 24 and further into the saturator 22 from above. Here it dissolves the fresh gas rising in countercurrent from bottom to top and leaves the saturator 22 below via valve 4 and line 6 and is, as before, from the circulation pump 7 pressed into the reaction vessel 11 via the line 8 together with the catalyst K. Depending on the amount of fresh gas that is introduced into the reaction vessel in dissolved form the amount of fresh gas that is fed directly into the Reaction vessel is pressed.

If the gas is only introduced into the reaction furnace in dissolved form, in this way, a pressure is maintained in the reaction system which is 5 to 20 atmospheres above the gas pressure of the acetylene is at the respective reaction temperature. But you can also do that work so that a small amount of gas in the furnace is outgassed again.

The discharge via the Aüstragsventil 27, with which the necessary working pressure is set, depressurized at the top of the reaction vessel and via the discharge vessel 28 and valve 29 discharged. At constant Inflow quantities is the The temperature in the reaction vessel is expediently regulated by the feed temperature; possible but is also a regulation by means of the inflow quantity.

The unreacted fizzy gas is finally cooled in the cooler 31, Washed in the gas scrubber 25 and fed to the fresh gas F via line 26, from where it can be reacted directly or in dissolved form in the reaction vessel 11 arrives. At the top of the reaction vessel 11 is a safety against excess pressure Valve 30 attached.

The advantage of the process is that you can use acetylene at the nominal pressure of the apparatus can work without danger, while otherwise because of the risk of explosion must remain well below this pressure, and secondly without it additional aids, such as external gas or liquid circulation, ensure thorough mixing the reaction solution is achieved.

The working method described can be used for all processes which work with an internal circulation of the reaction solution, as in the synthesis of cyclooctatetraene and in acrylic acid synthesis.

Example 1 An externally heatable reaction vessel was used 6 m long (D = 110 mm diameter), in which there is a central 5 m long inner Circulation pipe (D = 70 mm diameter) was located. The circulation pipe had one from the floor Distance of 200 mm.

The gas inlet pipe protruded 100 mm from below into the circulation pipe. The feed tube for the liquid ended 20 mm below the lower opening of the Circulation pipe in a nozzle with a diameter of 0.8 mm. At the top of the reaction vessel exhaust gas could be taken. The discharge was in the middle from the outer annulus taken. The fluid level could be checked with the help of an electric level indicator to be determined.

It was hourly through the supply pipe for liquid one Mixture of 45 1 of a 130% solution of water in tetrahydrofuran with 4.5 1 a catalyst solution is pumped into the reaction vessel.

The catalyst solution contained 0.130% Ni as NiBr2 and 0.05% Cu as Cu J in tetrahydrofuran. The working pressure was 60 atm. The working temperature was between 210 and 2150 C. At the same time, through the gas inlet pipe 8290 1 / hour of a gas mixture of equal parts by volume of acetylene and Koh lenoxyd injected. For discharging the contaminants contained or produced during the reaction Inert gases per hour were 230 l of exhaust gas from the gas buffer above the liquid taken. By letting down about 58.5 l / hour of liquid from the reaction vessel the level was kept about 250mm above the top of the inner tube.

The gas released during the expansion of the discharge (1500 l / hour with 54 0 / o acetylene) was fed to the fresh gas mixture required for the synthesis. The resulting discharge gave 10.5 kg / hour of acrylic acid by distillation won.

Example 2 In a reaction vessel with a capacity of about 200 liters (D = 200 mm Diameter, length L = 6000mm) were 1GO1 / hour 160 1 / hour benzene-tetrahydrofuran mixture with 160 hours of Ni-acetoacetic ester through a nozzle with a diameter of 1 mm into an interior Circulation pipe of 130 mm diameter pumped. At the same time, 20 Nm3 / hour of acetylene were produced blown into the circulation pipe, of which 7 Nm3 / hour were consumed. 10 Nm3 / hour were received back as fizzy gas, while derkest in gaseous form through the discharge valve went. The working pressure was 20 atm and the temperature was between 115 and 1200 C held. In the reaction vessel there were 5 temperature measuring points distributed over the length appropriate.

The maximum temperature difference between these measuring points was 20 C. The discharge contained an average of 6 kg of cyclooctatetraene per hour.

EXAMPLE 3 A benzene / tetrahydrofuran mixture of 150 l / hour was poured into a saturator up to a concentration of 1001 acetylene per liter of solvent and saturated then pressed into the reaction system as in 2 through a nozzle of 1.2 mm diameter. 8 liters / hour of catalyst solution and 200 g / hour of Ni-acetoacetic ester were added in front of the reaction vessel contained, pumped into the inlet. At the same time, 5 Nm3 / hour acetylene were in blown the circulation pipe. The temperature was kept at 115 to 1250 C, the Working pressure was 20 atm. The temperature differences in the oven were between 2 and 30 C. The discharge contained an average of 6 to 6.2 kg of cyclooctatetraene per hour.

Example 4 A benzene-tetrahydrofuran mixture was mixed in 150 l / hour in a saturator Saturated to a concentration of 100 1 acetylene per liter of solvent.

They were then combined with the catalyst solution in front of the reaction vessel and pumped into the reaction vessel. The working pressure in the reaction vessel was 40 atü. No acetylene gaseous was introduced into the furnace. The other conditions were analogous to example 3. The maximum temperature difference was 30 C. The Discharge contained an average of 6.4 kg of cyclooctatetraene per hour.

Claims (3)

PATENT CLAIMS: 1. Process for converting acetylene with itself itself or with carbon monoxide and water in the liquid phase in the presence of dissolved or suspended catalysts at temperatures up to about 4000 C below Ignition limit of the dissolved acetylene, which is in addition to that consumed in the reaction Amount of acetylene supplied is measured so that there are only small acetylene gas spaces Can form in the reaction vessel and the acetylene either together in gaseous form with carbon monoxide and water at pressures up to 100 atmospheres or in the implementation with itself at pressures up to 20 atmospheres or, in a released state, at pressures up to 100 atü introduces into the reaction space, characterized in that the inner circulation of the reaction solution in the reaction vessel mainly by emitting one or more pulses in a circulation pipe arranged in the reaction vessel, part of the acetylene gas is relaxed in dissolved form containing jets of liquid as well as additionally through into the Circulation pipe reaction gas added from below is effected. 2. The method according to claim 1, characterized in that the Pressure in the reaction vessel is chosen so that in it only an amount of 0.1 to 3 percent by weight of the dissolved acetylene outgassed. 3. Apparatus for performing the method according to claim 1 and 2, characterized in that the diameter of the reaction arranged vessel Circulation tube about ten tenths to seven tenths of the inner diameter of the reaction vessel and one or more supply pipes into the lower opening of the circulation pipe for the pressurized substances to be converted. Printed publications considered: German Auslegeschriften Nr. 1028 563, 1029369.