DE1901870C3 - 05/23/68 Japan 34357-68 Process for the production of tetrahydrofuran and / or gamma-butyrolactone - Google Patents

Description

The invention relates to a process for the preparation of tetrahydrofuran and / or; -butyrolactone by catalytic hydrogenation of maleic anhydride, succinic anhydride, succinic acid or mixtures of these compounds or esters formed in the process.

It is known to catalytically hydrogenate maleic anhydride. In this hydrogenation, however, arise various compounds such as succinic acid, γ-butyrolactone, tetrahydrofuran and tetrainethylene glycol, and considerable difficulties arise in order to preferentially obtain tetrahydrofuran or tetrahydrofuran. > To produce butyrolactone.

In order to overcome the difficulties, according to the method of the USA patents 27 72 291, 27 72 292 and 27 72 293 describe the catalytic hydrogenation of maleic anhydride using a Nickel / molybdenum, cobalt / molybdenum, Raney cobalt, Raney nickel and nickel / chromium / molybdenum oxide catalysts carried out, in particular for the production of tetrahydrofuran in high Yield is required. to carry out the reaction either under high pressure or a large one Amount of catalyst to use.

It was also found that in the catalytic hydrogenation of maleic anhydride using of a nickel-containing catalyst even when the reaction is carried out under high hydrogen pressure Maleic anhydride turns into a pitch-like mass at high temperatures, while at low temperature and longer reaction time, the water formed with the amber Stinic anhydride reacts to form succinic acid and which even at high temperatures catalytic hydrogenation is not easily accessible.

At high temperatures, succinic anhydride is hardly converted into succinic acid. These difficulties tries to eliminate the process known from JA-PS 7 40 655, in which the catalytic Hydrogenation using nickel-containing catalysts in a two-step process is carried out. _

This process mainly produces butyrolactone or tetrahydrofuran can be obtained in good yield when using maleic anhydride at fairly low temperature and pressure in the presence of a nickel-containing catalyst «1 succinic anhydride converts and the reaction product obtained then under rather high temperature and catalytically hydrogenated at fairly high pressure

However, this two-stage process has the disadvantage that when using a single reactor The reaction temperature must be controlled according to the progress of the reaction or that optionally two reactors connected in series must be used under different conditions operated to ensure optimal reaction conditions.

In the latter case it is not necessary change the reaction temperature over time / u, but it is not easy to use the highly viscous, pasty product in which considerable amounts of succinic anhydride or succinic acid are precipitated are present and the catalyst used is suspended. at high temperature and high pressure from the first reactor to the second reactor. . .

A high heat of reaction occurs in the hydrogenation reaction on. for example in the hydrogenation of maleic anhydride to tetrahydrofuran and Water in the liquid phase 76 kcal / mol and when using succinic anhydride as the starting material for the same reaction is 46 kcal / mole.

In the previously used process for the preparation of tetrahydrofuran by hydrogenation of Maleic or succinic anhydride or succinic acid were generally temperatures of at least 150 C and pressures of at least 50 atmospheres applied and a catalyst suspended in the reaction solution used. Around To obtain tetrahydrofuran in high yield, the temperature must be avoided while avoiding a local overheating of the catalyst can be regulated accordingly. To this end, one is very complete and complex cooling device required.

The methods known up to now have been carried out to a limited extent. Located in batch hydrogenation However, there is a high proportion of succinic acid in the reactor, and the water content increases with it progressive reaction.

These components rapidly reduce the activity of the hydrogenation catalyst. Through this there is an increased formation of by-products.

By contrast, the method according to the invention eliminates the disadvantages of the known methods and it is then possible to use tetrahydrofuran in an economical one-step process and - / - butyrolactone to be produced selectively and in good yields.

The method of manufacture according to the invention of tetrahydrofuran and / or; -butyrolactone by hydrogenation of maleic anhydride. Succinic acid

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jtnhydride, succinic acid or mixtures of these compounds or esters formed in the liquid phase in the presence of a nickel catalyst elevated temperature and pressure is characterized in that maleic anhydride, succinic anhydride, Succinic acid or mixtures of these compounds or those formed during the hydrogenation Esters together with y-butyrolactone in liquid Phase continuously introduced into a liquid mixture of the anhydride in question and j-butyrolactone and with an excess of hydrogen in the presence of a nickel containing catalyst at a temperature of 180 to 280 C and below hydrogenated at a pressure of 70 to 200 atmospheres and at the same time the hydrogenation product formed withdraws gaseous together with excess hydrogen from the reaction system, then condenses and separates y-butyrolactone from the liquid portion, some of which is returned to the reaction vessel is recycled, while the tetrahydrofuran is separated in the usual way.

This process achieves a long service life for the catalyst, as it is, on the one hand, the starting material is supplied only to the extent of its consumption and on the other hand gaseous reaction product is constantly withdrawn.

The continuous implementation of the method according to the invention also enables a economical hydrogenation of the starting materials in question, since the reactor is constantly in operation and the subsequent steps for emptying the reactor, separating off the reaction product and catalyst can be avoided.

Since in the process according to the invention, the tetrahydrofuran or γ-butyrolactone obtained im The amount of its formation is withdrawn in gaseous form, a smaller amount of undesirable forms By-products such as lower alcohols e.g. B. n-butanol and n-propanol. The formation of these by-products is proportional to the concentration of tetrahydrofuran in the reaction solution. You can therefore be suppressed by carrying out the hydrogenation reaction according to the invention.

The starting materials to be used, namely maleic anhydride, succinic anhydride, succinic acid and mixtures of these compounds or esters formed in the hydrogenation are in the form fed to the reaction system in a melt or solution. These substances can then also be used if they contain small amounts of maleic acid.

The following reaction scheme illustrates the process according to the invention using maleic anhydride as an example in the presence of a nickel-containing hydrogenation catalyst:

CH, CH ₁

O = C

C = O + 2H ₂

(B)

CHi CHt

(C)

CH =

O = C

CU

C = O + H,

55

60

(A)

CH ₂ CH ₂

i!

O = C C = O

- CH, C = O

y-butyrolactone CH ₂ CH ₂

CH, C = O + 2 H,

CH ₂ CH ₂

i '

- »CH, CH, O

Tetrahydrofuran

The reaction (A) proceeds at a very high reaction rate from, so that the maleic anhydride supplied as the starting product to the liquid reaction medium is instantaneously hydrogenated and in Succinic anhydride is converted, which at the same time by the liquid present in the reactor Intermediate products of the reaction is diluted. Concentration is therefore in the steady state of maleic anhydride in the liquid of the reaction zone is very low.

With the help of nuclear magnetic resonance absorption spectral analysis it was actually found that no maleic anhydride was in the liquid phase the reaction zone was present in the steady state.

By "steady state" are to be understood process conditions under which the used Starting material is supplied in an amount equivalent to that in the gas phase from the reaction system corresponds to removed reaction product. The inventive method is not, however, on one Working under the stated conditions of the steady state is limited, but it can can be operated at any desired feed and discharge speed, provided that that the reaction zone is kept in the liquid phase.

The composition of the liquid phase of the reaction zone in the steady state can, for example from 35 to 85 mole percent v-butyrolactone. ! up to 10 mole percent tetrahydrofuran, 2 to 15 mole percent Water. 10 to 20 mole percent hydrogen. 0 to 20 mole percent succinic acid. 0 to 60 mole percent of a polyester and other compounds such as propanol. Butanol and propionic acid exist.

Da, as stated above, the concentration of maleic anhydride in the liquid reaction zone is very low, no tarry mass is formed even at high temperatures. The inventive The method therefore offers the advantage that no two

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step process is more necessary. in which the reaction first takes place at low temperatures and is then stirred at high temperatures.

In the previously known processes for the production of tetrahydrofuran by hydrogenating maleic anhydride or succinic anhydride in the presence of a nickel-containing hydrogenation? katal \ - The tetrahydrofuran obtained is sators in the reactor with formation of butanol and propanol hydrogenated further as a by-product, thus lowering the yield of tetrahydrofuran.

Because in the process according to the invention the tetrahydrofuran to the extent of its formation is withdrawn from the reaction zone together with excess hydrogen, these side reactions are suppressed and thus obtained high yields of tetrahydrofuran. In addition, the The concentration of tetrahydrofuran in the gas phase is much higher than in the liquid reaction zone, so that Tetrahydrofuran can be obtained in high purity.

When carrying out the method according to the invention is carried out simultaneously with the removal of the Reaction product introduced in gaseous form to excess hydrogen in the liquid reaction zone to speed up the evaporation.

According to the process of the invention it is possible to use either γ-bulyrolactone or tetrahydrofuran as the main product to manufacture. Since the speed of the partial reaction (C) described above is slower than that of the partial reactions (A) and (B). it is possible by adjusting the hydrogen supply to manufacture one of these products as the main product.

For example, y-butyrolactone can be obtained as the main product if the amount of supplied hydrogen increased and the y-butyrolactone obtained immediately after its formation removed from the reaction system, while tetrahydrofuran is then obtained as the main product when the amount of hydrogen supplied is reduced, so that the residence time of γ-butyrolactone in the reaction zone is increased. This is another benefit of the procedure in accordance with the designation.

In addition, the method according to the invention has the advantage that it is less developed the heat of reaction makes the reaction temperature lighter can be regulated than in the known method. This is because it contributes to the formation of tetrahydrofuran and water in the gas phase, heat of reaction generated by hydrogenating succinic anhydride at 235.degree 26 kcal / mole and when using maleic anhydride 57 kcal / mole and is therefore essential lower than in the liquid phase.

On the other hand, the latent heat of γ-butyrolactone at 235 C is 9.2 kcal / mol, so that the Theoretically, absorption of the entire heat of reaction by the latent heat of γ-butyrolactone sufficient additional γ-butyrolactone in an amount of 2.7 mol / mol of the succinic anhydride used and to add 6.2 mol / mol of maleic anhydride used.

The advantage of easier adjustability of the reaction temperature can therefore be further increased be that additional γ-butyrolactone is added to the reaction zone in addition to the γ-butyrolactone obtained and together with the obtained Reaction product removed by evaporation. The latent heat of the additional γ-butyrolactone is consumed Heat of reaction, and the reaction temperature can therefore be kept at the desired value without the need for expensive cooling units in the reactor.

In practicing the process, however, it is possible to theoretically follow the above given required amounts of additional y-Buiyro-

To reduce lactone considerably by doing this, one must provides a fairly simple cooling system in the reactor and / or the γ-butyrolactone to be fed cooled down to a fairly low temperature beforehand in order to use its sensible heat

In general, the amount added is: an additional y-butyrolactone 0.2 to 6 mol and preferably 0.4 to 2 mol / mol of the used Anhydride.

The γ-butyrolactone can be introduced into the reaction zone together with the starting material, or alternatively it can be vaporized γ-bulyrolaetone condensed in a condenser installed in the reactor and introduced into the reactor by reflux. The first of these options will be preferred because the starting material in y-Bui.yrolacton can be solved.

Since maleic anhydride and succinic anhydride are solids under normal conditions and it is nigh on impossible. to continuously feed these Sioffe in the solid state under high pressure to the reactor, it is necessary to convert them to the liquid state by prior heating. There Maleic anhydride, or succinic anhydride, easily dissolve in γ-butyrolactone is the introduction in the reactor as a solution very easy.

The evaporation of the reaction product and the generated and / or added γ-butyrolactone as Means for regulating the heat of reaction formed is supplied to the reactor by the amount of the excess hydrogen determined. The proportion of evaporated y-BiUyrolaeion therefore increases in the Measure. how to increase the hydrogen supply to the reactor. The amount of hydrogen supply is therefore adjusted to y-butyrolactone in accordance with the M en se to be evaporated.

On the other hand, the rate of evaporation decreases with the last-described type of supply of γ-butyrolaclone of tetrahydrofuran to that extent. in which its rate of formation decreases, reducing the concentration of γ-butyrolactone in the reactor increases, which in turn accelerates the reaction and thereby the speed the formation of tetrahydrofuran increases. This type of implementation has the advantage that the Reactor can be operated in a so-called self-regulating manner. Most preferred it is therefore to combine both working methods.

It was also found that in the process according to the invention, an increase in the reaction rate, an increase in yields and stable process conditions can be achieved that one in the liquid Reaction zone has a water content of 1 to 10 percent by weight, based on the reaction mixture

without a catalyst.

It was also found that in addition to the course of the reaction explained, other reaction processes take place, with the educated Bern-

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»Tinic anhydride succinic acid is produced with likewise formed 1,4-butanediol a polyester forms, which is then converted into tetrahydrofuran. Water plays a role in these reaction processes important role.

The course of the reaction can be controlled by regulating the water concentration in the reactor Reaction liquid can be determined.

Due to the continuous removal of the reaction product in the gas phase, in the case of the invention In the process, only an extremely small amount of 1,4-butanediol is present in the reactor. being as main Intermediates succinic anhydride, succinic acid, γ-butyrolactone and formed polyester is present. The polyester has the same chemical structure as one by dehydrating concentration product obtained from 1,4-butanediol and succinic acid, and its molecular weight increases to the extent. in which the water concentration in the reactor is reduced. Although this polyester finally hydrogenated again and converted into 7-butyrolactone or tetrahydrofuran using water will, the transfer speed will be the lower the higher the molecular weight increases. Therefore, if the water concentration in the Liquid the Rcaktanlcn in the reactor is exceptionally low. the polyester concentration becomes gradually higher, and the molecular weight of the polyester increases at the same time and thus decreases drastically the rate of formation of tetrahydrofuran from the polyester.

On the other hand, if the water concentration in the reactant liquid is too high. the concentration of maleic acid increases by reacting the maleic anhydride, which is used as the starting material, with water. Since the maleic acid produced in this way has a particularly high avidity in comparison with the other intermediate products, it strongly attacks the catalyst used. For example, when a nickel catalyst is used, the nickel present as a catalyst component dissolves in the reaction mixture, as a result of which the catalyst activity is reduced. Moreover, responding with a too high water concentration in the reaction liquid, present in the reactor succinic anhydride with water to form succinic acid addition of the water is due to the high concentration, the reaction rate of the poly esterbildung of succinic acid and-applied 1,4-butanediol decreased and the amount of succinic acid in the reactor therefore increases more and more . This increase in the content of succinic acid in the reaction system leads to a drastic decrease in the rate of formation of tetrahydrofuran because succinic acid is not only hydrogenated at a slow rate but also has a greater affinity for the catalyst than the other intermediates.

However, all these disadvantages can be eliminated at the same time by the above-mentioned measure of regulating the water content.

Although the preferred range of the water content varies depending on the type and composition of the catalyst used and its concentration as well as the reaction temperature, the reaction pressure and other factors determining the reaction rate, such as the ratio of γ-butyrolactone to the dicarboxylic anhydride used as starting material , this is generally 2 to 6 percent by weight, based on the reaction mixture without catalyst.

The adjustment of the hydrogen concentration in the liquid reaction mixture within the specified Area can be done in any way, for example by regulating the reflux of the Reaction formed water or by special addition of water in uas reaction mixture.

The reaction is carried out at a temperature of 180 to 280 C and under a pressure of 70 to 200 atmospheres performed.

Any nickel-containing hydrogenation catalysts which are suitable for the hydrogenation can be used as the catalyst of maleic anhydride can be used, such as nickel or a solid solution made of nickel and rhenium with or without supported catalysts. Preferably these are nickel containing hydrogenation catalysts by suspending them in the liquid phase of the reaction zone in used in a proportion of 0.5 to 30 percent by weight.

The residence time of the maleic anhydride depends considerably on whether γ-butyrolactone or tetrahydrofuran is preferred as the main product. In general, however, the residence time is about one Range from 3 to 20 hours.

For carrying out the method according to the invention the device shown in the drawing, which has a hydrogenation reactor 1, a condenser 2. a gas-liquid separator 3. a separator for γ-butyrolactone 4, a container for γ-butyrolactone 5 and the preheaters 6 and 7 contains.

The starting materials are fed to the preheater 7 through line 18 and y-butyrolactone through line 16 supplied, and after preheating in the preheater 7, the mixture in question is the Reactor 1 fed through line 9, t'over the In line 9, the catalyst suspended in the liquid starting material is introduced into the reactor. The dissolution of the starting material in γ-butyrolactone can either in the preheater 7 or m a separate device not specified here.

Gaseous hydrogen is introduced into the preheater 6 via a line 17, and after the preheating, the hydrogen is introduced into the reactor 1 via the line 8. The reactor 1 can be provided with a suitable stirrer. The exhaust gases from the reactor 1 are passed through the line K into the condenser 2, in which an oil component condenses, and then via the line 11 into the gas-liquid separator 3, in which the gas phase is separated from the condensate phase.

Part of the gas phase obtained, which predominantly consists of hydrogen, is supplied via line 1! withdrawn from the reaction system, while the remaining portion via line 12 in the dei Reactor 1 is recycled.

The separated liquid phase is passed through line 1 into the distillation column for separating off y-butyrolactone 4, in which the y-butyrolactone is separated off from the reaction product. The separated y-butyrolactone is then brought through line 15 into the container 5, from the last «

609 627/76

ίο

can be returned to reactor 1 via line 16.

The reaction product freed from y-butyrolactone, which mainly consists of tetrahydrofuran with certain Amounts of water, alcohol and acid is passed through line 14 into a distillation column passed for the separation and purification of tetrahydrofuran, separated in the pure tetrahydrofuran and is won.

Hiviihmno

which dilute with carbon dioxide! was. brought.

Example I.

The response was one in the drawing device shown is carried out under a reaction pressure of 120 atmospheres.

The starting charge in reactor 1 was 320 kg of 60 percent by weight γ-butyrolactone

The device shown in the drawing can be ίο and 40 percent by weight succinic anhydride

can be modified in various ways. For example, in the device shown, the Ό1 component the gas phase from the reactor 1 is completely condensed in the condenser 2 and y-butyrolactone after its separation in the separation device 4 can be returned to the reactor. However, it is just as possible that the Reaction formed gas phase to partially condense in a partial condenser and thereby the high-boiling point To liquefy y-butyrolactone for recycling into the reactor and the gas phase from the the γ-butyrolactone has been removed, then subjected to cooling, separating and cleaning operalions.

The nickel used in Examples 1 to 8 below and in Comparative Examples 1 a) and 2a) / Rhenium catalyst was prepared as follows.

100 g of powdered kieselguhr were added to an aqueous solution of 500 g of nickel nitrate Ni (NO ₃ I ₂ · 6 H ₂ O in 400 g of distilled water, and the

- - ττΐΓ . Χ *: ι: _i_

Introduced standing mixture, which was preheated to 235 C. 32 kg of the nickel / Rhenium catalyst suspended on kieselguhr as a carrier and the one atomic ratio of rhenium to Nickel of 0.05.

The reactor 1 was then in the preheater 6 at 160 C preheater gaseous hydrogen over the Line 8 with a feed rate of 1800 NnvVh. and maleic anhydride and γ-butyrolactone. preheated to 180 ° C via line 9 at feed rates of 98 kg / hour. or 86 kg / hour fed. At this point the temperature of the reactor was 235 C.

The gas phase emerging from reactor 1 was cooled and condensed in condenser 2 and then separated unreacted hydrogen gas in the gas-liquid separator 3 and partly returned through the line 12, while through the Leitmm 13 liquid Rcak-

tene mass was with the help of a mixer 30 tion product at a speed of 204kg /

Kneaded for 1 hour to obtain a deep green sludge-like product. An aqueous solution consisting of 200 g of ammonium carbonate (NH ₄ I / CO ₁ dissolved in 200 g of distilled water) was gradually added to this sludge-like product, the solution being stirred. A yellow-green precipitate was formed in the resulting mass. The precipitate thus formed was separated from the resulting mass by filtration, and the separated solid product was washed twice with distilled water To 30 g of the powdery basic nickel carbonate thus obtained was added 2.0 g of rhenium heptoxide Re ₂ O- in the form of an aqueous solution, and the resulting mass was kneaded.

Analysis of the liquid withdrawn through line 13 showed that it was 25 mole percent y-butyrolactone. 21.9 mole percent tetrahydrofuran.

1.2 Moipro / cnt propane !,!.! Mole percent BuUinol. 0.8 mole percent propionic acid and 50 mole percent water. The yield of tetrahydrofuran was 87.6 mole percent based on maleic anhydride.

The sampling and analysis of the liquid phase of the reactor 1 gave a composition of 54.7 mole percent - butiyrolactone. 4.0 mole percent Tetrahydrofuran. 0.2 mole percent propanol. 0.3 MoI-prczerit Büianui. 0.2 percent propiolic acid.

8.4 mole percent succinic acid and 21.5 mole percent polyester.

The liquid withdrawn through line 13 (204 kg / hour) was fed into the device for separation initiated by y-butyrolaetone, in the y-butyrolactone

Kneaded product was separated off at a temperature of 50 and dried through line 15 into the container S 110 to 120 ° C. for 12 hours. The product thus obtained was passed (90 g / h; purity 99.9 weight-dried product was then the
Reduction under a stream of hydrogen at a

Temperature from 200 to 250 ⁰ C subjected. The percent). The product obtained at the upper end of the separating device 4 and consisting essentially of tetrahydrofuran (14 g / hour; 58.6 percent by weight

Flow rate of gaseous water - 55 THF. 33.5 percent by weight water, 7.9 percent by weight

Percent of other ingredients) was determined by wire I ^ gelei in the distillation column for tetrahydrofuran tet and there rectified by distillation under normal pressure, an azeotropic mixture of tetrahydro

substance was set to a value in the range from 2 to 101 / hour. adjusted so that the reaction temperature was kept constant, even if during the

Heat was released in the course of the reduction reaction.

The catalyst obtained in this way, which by reduction is 60 furan and water with a boiling point of 63.5

of the dried product was obtained in a stream of hydrogen, the 5.66 percent by weight of water

th was ^{cooled to 150 0} C and then contained. The mixture thus obtained was then removed

left to stand overnight with the current flowing from under a pressure of 7 ke / cm ² over 1 atm

Gaseous hydrogen is adorned by a stream of, whereby through a discharge opening at the top Gaseous carbon dioxide at a flow rate of 65 at the end of the distillation column forms an azcotropic gem

from 21 / hour was replaced, per so with a stream of tetrahydrofuran and water with a boiling point

Catalyst treated with gaseous carbon dioxide at 135.5 C and 12 percent by weight water

Sator was gradually supplied with air. and by taking it from the bottom of this distilla

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tion column tetrahydrofuran of a purity of 99.9 percent by weight were obtained. That at the top of the rectification column using Azeotropc obtained from pressure Geirisch was in the rectification column, which was under normal pressure was operated, in which the first rectifying distillation of the reaction product was carried out.

Example 2

The reaction was carried out in an apparatus shown in the drawing and under a reaction pressure of 120 atmospheres.

In the reactor 1 were 340 kg of 60 weight percent ^ -Bulyrolacton as an initial charge and 40 percent by weight succinic anhydride existing mixture and 34 kg of the Nickel / rhenium potassium hydroxide applied to diatomaceous earth. which has an atomic ratio of rhenium to Nickel of 0.05 was suspended.

Gaseous hydrogen, which had been heated to 190 ° C. in the preheater 6, then passed through line 8. Introduced into reactor 1 at a rate of 2600 Nm 'hour and maleic anhydride and ^ -butyrolactone preheated to 190 ° C. via line 9 in an amount of 98 kg' ski. or 12Okg'h. fed. At this point in the process, the temperature of the reactor was 235 C. The gases withdrawn from the reactor 1 through the line 10 were cooled in the condenser 2, condensed, and then unconverted gaseous hydrogen was separated in the gas-air-conduction separator 3 and Part returned to the system, while through line 13 liquid reaction product in an amount of 237 kg / hour. received.

Analysis of this liquid gave a composition of 33.3 mole percent γ-butyrolactone. 20.2 mole percent tetrahydrofuran. 0.82 mole percent Propanol. 0.3 mole percent bulanol. 0.4 mole percent propionic acid and 44.5 mole percent water. The yield of tetrahydrofuran from maleic anhydride was 9i * vioi (> iu / _ £ iU.

The analytical examination of a sample of the liquid contents of the reactor 1 showed that it was 64.1 mol% of v-butvrolactone. 2.7 mol percent tetrahydrofuran, 0! Mole percent propano !. 0.2 mole percent butanol. 0.2 mole percent propionic acid. 7.1 oil percent succinic acid. Contained 18.4 mole percent of polyester and 7.2 mole percent of water.

Further work-up of the withdrawn through line 13 reaction products were according to Example 1 was obtained and tetrahydrofuran -, - butyrolactone in a purity of 99.9 weight percent, respectively.

Example 3

The reaction was carried out with the aid of a device in which part of the r-butyrolactone is returned to the reactor 1 with the aid of a partial condenser 2.

The device consisted of a reactor 1 with an internal diameter of 110 mm and a height of 230 mm, the contents of which could be stirred with the aid of an inductive stirrer, a partial condenser 2 with an internal diameter of 30 mm and a height of 550 mm, which was connected to the reactor 1 was in connection, a water-cooled condenser 3. which was connected to the partial condenser 2. a gas-liquid separating device 4. which was in connection with the condenser 3 and the following pipes connected to the reactor 1: a pipe for introducing the starting material (acid and / or ^ -butyrolaetone) and the catalyst, a pipe for the Introduction of hydrogen and a pipe to take samples of the reaction liquid in the reactor. to determine their composition.

30 g of a nickel / rhodium catalyst (atomic ratio Re: Ni 0.06) in the form of a suspension in 1 kg of a mixture consisting of 40 percent by weight succinic anhydride and 60 percent by weight butyrolaetone were introduced into reactor 1 through the feed line. The reaction was carried out at a temperature of 260 C. a pressure of 120 atmospheres with an amount of hydrogen supplied of 2 Nm ¹ style.

started with stirring at 1000 rpm.

As the reaction proceeded, tetrahydrofuran formed became. γ-Butyrolactone and by-products are withdrawn in the vapor phase together with excess hydrogen fed in. In the partial condenser 2, part of the; · -Βιιΐ \ ιτ> lactone was separated and returned to the reactor, while the vaporous mixture consisting essentially of tetrahydrofuran was passed through the line 10 into the condenser 3 and was condensed and liquefied there, and while in the gas-liquid separator 4 a separation of a condensed liquid product from excess hydrogen was carried out and excess hydrogen was removed through line 14.

The condensed liquid product remains in the lower part of the gas-liquid separator and is drawn off through line 15 if desired.

The condensed liquid product obtained in the above-described manner became every 10 minutes deducted and its amount was determined. Then molten maleic anhydride became continuously Introduces in equal amounts through the supply line. The temperature of the partial condenser 2 and the delivery rate of Wii> »ersii-rfi were adjusted so that the amount of that remained in the lower part of the gas-liquid separating device 4 condensed liquid product 345 g / hr. was, corresponding to a dwell time of 2.9 hours.

The reaction was carried out for 8 hours under the above conditions. The yield of the condensed liquid Steady state product was 78 mole percent tetrahydrofuran, 5 mole percent - / - butyro lactone and 17 mol percent n-propanol, n-butanol and < Propionic acid.

Example 4

The procedure was analogous to Example 3, with the modification that a starting batch of 70 Mo percent maleic anhydride and 30 Molprozer j-butyrolactone existing mixture used un 30 g of a nickel / rhenium catalyst with a Atomic ratio of rhenium to nickel of 0.03 was used.

The reaction was carried out continuously for 8 hours in such a way that the temperature di

Partial condenser 200 C and the hydrogen supply 4001 / hour. fraud.

The residence time of the reaction mixture in the reactor under steady-state conditions was 5.5 hours and the concentration of j-butyrolactone in the liquid condensed in the condenser 3 was 1 mol percent of tetrahydrofuran was formed with a selectivity of 92 mole percent.

Example 5

The reaction was as in Example 3 with the same starting materials at the same reaction temperature and the same pressure carried out and where 30 g of a nickel / rhenium catalyst with an atom (5 rhenium to nickel ratio of 0.03 were used.

The reaction was carried out continuously for 30 hours, the temperature of the partial condenser and the reaction temperature being 260 ° C. and the hydrogen in an amount of 1500 l / StiT. was fed. The liquid with γ-butyrolactone condensed in the partial condenser was continuously returned to the reactor and maleic anhydride was continuously added in an amount that corresponded to the rate at which tetrahydrofuran, n-propanol, n-bulanol and propionic acid were distilled off from the liquid condensing in condenser 3 became.

The residence time under steady state conditions was 2.8 hours and the speed the formation of tetrahydrofuran 10 6 g / hour. Tetrahydrofuran was produced with a selectivity of 85 Molpri> 2: ent generated.

Example 6

The procedure was analogous to Example 3, with the modification that the starting material was one from 70 mol percent Use succinic anhydride and 30 Molprozenl y-butyrolactone existing mixture! would and 30 g of a nickel / rhenium catalyst with an atomic ratio Re: Ni of 0.03 are used would.

The reaction was carried out continuously at a temperature of the partial condenser of 200 ° C. for 8 hours and with a hydrogen supply of 400 liters / hour. accomplished.

A dwell time in the steady state of 5.5 hours, a concentration of; -but \ ro-

Table 1

35

40

45 lactone in the condensed liquid of l.o MoI perzeni and a selectivity of tetrahydrofuran formation of 92 molar percentages was obtained. The results correspond completely to those of example 4.

Example 7

The device described in Example 3 was used. The reactor was charged with 1000 g of a mixture consisting of 40 mol percent succinic anhydride and 60 mol percent butyrolactone and 30 g of a nickel / rhenium catalyst with an atomic ratio of rhenium to nickel of 0.03 and the reaction was carried out with a supply of 2 Nm ³ hours. Hydrogen started at a temperature of 260 C and a pressure of 1 20 atmospheres.

After the start of the reaction, water was added to the reaction sintering in various amounts, namely 0g / hour. (Experiment 11, 50g / hour (Experiment 2). 75g / sid. (Experiment 3) and 3 1/2 g / hour (Experiment 4). When carrying out the reaction, the rate of the supply of excess hydrogen was adjusted so that that the dwell time of the reaction mixture in the reactor 3 was 3 hours and ^ -Buyrolaeion and maleic anhydride were fed in such amounts that they match the amounts of buttone or tetrahydrofuran present in the partial condenser 2 b / w. in the condenser 3 Propionic acid, butanol and propanol correspond to the fact that the temperature of the gas withdrawn through line 10 was kept at the same value as the reaction temperature, namely at 260.degree.

The reaction was carried out continuously for 30 hours. That in the partial capacitor 2 together Vaporous product obtained with excess hydrogen was converted with the aid of the condenser 3 completely condensed. Thereafter, with the help of a gas-liquid separator, which then followed the condenser was arranged, the separation into liquid (end product) and hydrogen was carried out.

The composition of the obtained liquid product was determined analytically. The educational speed wedge \ on Tetrahydrofuran, the feed rates of ^ -butyrolactone and maleic anhydride in the steady state and the concentration of water. - butyrolactone. Succinic acid uiid formed Polyesters in the reaction liquid wedge are in the table below! compiled.

attempt Water-
Z u drive
speed
age Bildiinjis-
jieschwin-
diykeit ion
Tetrahydro
furan Speed
age of
Muleinic acid
anlndrid
/ 11 full I. Speed
age of
; -Bulyro-
lactone intake Together: the R
Weight percent)
Water --BuI) ro!
acton 38 reaction liquid wedge
I- amber-
acid Po Iy Sid.) Ij: Sld.l (J! SId I (ι: hour 63 1 O 40 64 220 0.8 65 5 51 2 50 66 108 192 1.9 62 5 25th 3 75 75 123 176 3.1 8th 20th 4th 130 62 K) I 199 3.6 10 20th

Example 8

A reactor with an inner diameter of 240 mm and a height of 440 mm was used. which was provided with an inductive stirring device. There was an exit port at the top of the reactor provided, from which the rcaklions-

Hydrogen carrying products escapes, which is introduced into the gas phase part of the reactor at 80 ° C was v / orden.

Four pipelines were connected to the reactor 1; H. (a) a pipeline for introducing the used starting acid (and / or the anhydride) and / or of y-butyrolactone, (b) a line to Introducing hydrogen, (c) a line for drawing off liquid from the liquid part the reactor contents and (d) a line for withdrawing the vaporous product together with excess Hydrogen (10).

Otherwise, the device used corresponded to that used in Example 3.

1 kg of a nickel / rhenium catalyst was added to this reactor with an atomic ratio of rhenium to nickel of 0.06. After that, as One-off initial batch of 10 leg --buivrolacfon introduced.

A starting material made up of 50 mole percent maleic anhydride then became the continuously supplied starting material and 50 mole percent of 7-butyrolaclone mixture initiated.

(0

The reaction was carried out under reaction conditions which include a reaction ^{pressure of 120 kg / cm 2} , a reaction temperature of 250 ° C., a hydrogen ^{supply rate of 23 m 3} / hour, a temperature of the exiting gases of 210 ° C. and different rates of water supply, namely Okg / hour (Experiment 5), Ü, 3kg / h. (Experiment 6), and 0.7 kg / hour. (Experiment 7) included. The raw material was introduced in such a manner that the liquid level in the reactor was kept at a predetermined level.

In this example, the feed rate of the starting materials and the hourly rates with which in the gas phase withdrawn from the reactor 1 water, tetrahydrofuran, propanol, Butanol, propionic acid, butyric acid and γ-butyrolactone were distilled, which are listed in the following table 2 shown values.

The proportions of water, butyrolactone, succinic acid and polyester obtained in these experiments in the reaction liquid are shown in Table 3 » represents.

Table 2

Attempt delivery of the deslillation rate (kg hl

of the starting material water, tetrahydro-propanol

furan (kghour

Butanol

Propionic acid butyric acid: -Bul> rolacion

5 1.330 0.323 0.543 0.027 0.019 0.019 0.004 0.381 6th 1.610 0.617 0.597 0.013 0.019 0.025 0.005 0.612 7th 1.080 0.885 0.378 0.007 0.009 0.023 0.003 0.464

Table 3

attempt

Composition of the reduction fluid (Weight percent)

water

3.8
5.1

7.7

y-butyroiactone

73.9
83.8
76.9

Amber acid

2.48 2.30 2.92

polyester

40

45

7.99 3.22 5.0K

Example 9

Using the same apparatus as in Example 3, continuous operation was carried out under the following conditions worked

1. Catalyst used:

Ni-Re-Mo — SiOj ■ Al ₂ ü, catalyst. e »

Atomic ratio Re / Mi = 0.03. Atomic ratio Mo / Ni ~ 0.075. Weight ratio SiO _; , Al ₂ O ₃₁ Ni = 2.

2. Amount of catalyst used: 300 g.

3. First loading with starting material: 1 kg of a mixture of 40 mol percent succinic anhydride and ISO mol percent; -Bulyro-

4. Charging material:

A mixture of 85 mole percent maleic anhydride and 15 mole percent --butyrolactone.

5. reaction pressure: 120kg / cm ² ,

6. Flow rate of H ₂ :

9 to 15Nm \ 'hours (depending on the Composition of the material inside the reaction vessel, the value was set selectively).

7. The reaction temperature and the flow rate of H ₂ were selectively chosen so that THF (tetrahydrofuran) and -BL (v-butyrolactone) in an amount of 600gh. could be formed.

When the catalylic activity was reduced. the reaction temperature was increased to at normal Values to stay. The results obtained are summarized below, the values for Tetrahydrofuran and - / - butyrolactone in the same way as in Example 1 were determined. The amount of feed of y-BL initially added is in Does not include the amount given in the table below for the formed; -BL.

The table also shows the amount of THF formed. based on the total amount of the reaction products as selectivity S ₁ . and also the amount of THF and --BL formed. based on the total amount of products formed as selective

activity S ₂ , the values being calculated as follows.

S ₁ =

5, =

(THF)

(THF) + (by-products) '

(THF) + (γ- BL)

(THF) + (--BL) + "(by-products)

(The indication (y-BL) means the amount of J-BL obtained, from which the amount of the first charge y-BL has been withdrawn.)

The results are as follows:

The treated catalyst was gradually brought into contact with air diluted with nitrogen. The reaction between the catalyst and the air diluted with nitrogen was carried out in such a way that that the heat generated by the catalyst during the reaction leads to a temperature increase of did not lead to more than 50C.

Example 10

According to Example 3, γ-butyrolactone was produced in a continuous procedure under the following conditions manufactured.

Reak
functional
length of time React
functional
tem-
temperature Rate of education
age r-BL selectivity S, (Hours.) CC) (g / h) 90 (Weight percent) 93 THF 200 S ₁ 92 100 242 800 220 9! 90 250 248 690 230 90 90 500 250 600 300 88 89 750 254 600 88 1000 254 590 87

"5

262

650

250

87

89

The catalyst given under 1 above has been prepared as follows:

To an aqueous solution of 500 g of nickel nitrate Ni (NO ₃ I ₂ 6H ₂ O in 400 g of distilled water, an aqueous solution of 200 g of ammonium carbonate (NH _{4 I 2} CO, in 400 g of distilled water) was gradually added with stirring a yellow-green precipitate was formed in the obtained mass. The precipitate thus formed was then separated from the resulting mass by filtration, and the obtained solid product was washed twice with 200 g of distilled water. To the washed solid product, SiO ₂ · Al ₂ O was added , was added in such an amount that the weight ratio of SiO ₂ ■ Al ₂ O ₃ / Ni 2, and the resulting mass was kneaded. The kneaded mass was then dried for 24 hours at a temperature of 110 to 120 ° C., whereby SiO _{2 -Al 2} O, was obtained as a carrier in powdery basic nickel carbonate. Rhenium heptoxide and ammonium molybdate in the form of an aqueous solution were added to the powdery basic nickel carbonate thus obtained aqueous solution was added in such an amount that the Alom ratios Re / Ni and Mo / Ni became 0.03 and 0.075, respectively, and the resulting mass was kneaded. The kneaded product was then dried at a temperature of 110 to 120 ° C. for 12 hours. The dried product was then subjected to reduction under a stream of gaseous hydrogen at a temperature of 150 to 250 ° C. for one hour and then to reduction at a temperature of 450 ° C. for 3 hours. The catalyst obtained by reducing the dried product was cooled to a temperature of 150 ° C. and then left to stand in the form obtained overnight, the hydrogen stream being replaced by a stream of gaseous carbon dioxide. With the one with carbon dioxide

1. Catalyst used:
Ni-Mo-Tl-SiO ₂ ■ Al ₂ O ₃ catalyst as described below.

2. Amount of catalyst used: 100 g.

3. First loading with raw material:
How crazy Example 9.

4. Loading:

As in example 9.

5. Reaction pressure: 80 kg / cm ² .

6. Flow rate of the H ₂ :
24 to 28 Nm ³ / hour

7. Amount of liquid formed:

The reaction temperature was optionally changed so that γ-butyrolactone in an amount of about 1.3 kg / hour. was formed.

The results obtained are summarized below, with the values for the respective Reaction products have been determined in the same way as in Example 1.

(THF) + "(f-BL) + (by-products) '

(The above expression - / - BL means the amount of; -Butyrolactone recovered minus the initial charge of; -BL.)
The results are as follows:

Reuklionsduuer
AC Feedback
lcmpenilur Amount of ge
formed rivers
sweetness Selectivit; ⁴⁵ (hours) (C) | kg / hour) (Weight
Percent) 100 265 1.88 87 ⁵⁰ 200 246 1.30 93 300 250 1.30 95 400 250 1.38 95 500 250 1.32 95

55 The catalyst used under 1 above has been prepared as follows:

To the yellow-green cake made of basic nickel carbonate. obtained by precipitation from a mixture in which an aqueous solution of Ammonium bicarbonate was added to an aqueous solution of nickel acetate. became a added aqueous solution of ammonium molybdate and an aqueous solution of thallium nitrate so that the atomic ratios of Mo / Ni and Tl / Ni were 0.06 and 0.03, respectively. The mass obtained was thoroughly kneaded so that their composition became homogeneous, with mud-like mixed

19 Ol Il

Cake containing nickel, molybdenum and thallium was obtained. To the mixed cake thus prepared, silica-alumina (containing 13% by weight alumina) having a particle size corresponding to a sieve size of 0.177 to 0.250 mm (ASTM sieve of 60 to 80 mesh) was added so that a weight ratio of nickel to silica -Alumina of 1: 1 was achieved. The resulting mass was kneaded and simultaneously dried and cured by heating to a temperature of 70 to 9O ⁰ C. ^{The product obtained was further dried for} a whole day and night with the aid of a dryer at a temperature of 100 to HO 1- C. The powder thus obtained was then heated under a mixed gas stream having a hydrogen to nitrogen ratio of 1: 2 to a temperature of 270 to 350 ^J C, and the thermally treated product was then heated under a stream of hydrogen at 450 C for 3 hours Subject to reduction. The solid product thus obtained by reducing the thermally treated product with the aid of gaseous hydrogen was cooled to a temperature of 150 ° C. and was then further cooled to room temperature, replacing the flow of gaseous hydrogen with a flow of gaseous nitrogen. The cooled product thus obtained was gradually brought into contact with air diluted with nitrogen so that the product was stabilized.

Example 11

An apparatus described in Example 3 was used and the reactor with 1000 g of one Mixture of 40 mol percent succinic acid, 60 mol percent γ-butyrolactone and 50 g of that in Example 3 specified catalyst charged and the reaction at a temperature of 270 "C and below a Pressure of 120 atmospheres started. Every 10 minutes after the start of the reaction, they were collected with the aid of a gas-liquid separator The amounts of liquid were measured, and maleic anhydride and one of the withdrawn ones were continuously added Amount of liquid supplied to the corresponding amount. The temperature of the particle capacitor and the amount of hydrogen supplied were controlled so that in the gas-liquid separator Liquid in an amount of 150 g / hour. condensed was, which corresponds to a residence time of 6.7 hours.

When the reaction was carried out continuously for 10 hours, after condensation and removing water to obtain a liquid composed of 69 mole percent tetrahydrofuran, 12 mole percent y-butyrolactone and 19 mole percent n-propanol, n-butanol and propionic acid.

Comparative example IaI

It was worked discontinuously, and in a reactor with 300 ml capacity were K) Ug Succinic anhydride for 2 hours in the presence of the catalyst used in Example 4 with hydrogen hydrogenated, using a reaction temperature of 270 C and a pressure of 120 atmospheres would.

Analysis of the reaction mixtures indicated that it was 46.1 mole percent tetrahydrofuran and 34.8 mole percent - / - butyrolactone contained.

Comparative example 2a)

Maleic anhydride was under the same conditions as in Comparative Example 1 a) with hydrogen hydrogenated. Due to a dangerous rise in the reaction pressure, the reaction was allowed to proceed difficult. After the reaction was complete, a large proportion of a tar-like mass became in the reaction product detected.

1 sheet of drawings

Claims (1)

Claim: Process for the preparation of tetrahydrofuran and / or γ-butyrolactone by hydrogenation of maleic anhydride, succinic anhydride, succinic acid or mixtures of these compounds or esters formed in the liquid phase in the presence of a nickel catalyst at elevated temperature and pressure, characterized in that maleic anhydride, succinic anhydride , Succinic acid or mixtures of these compounds or esters formed in the hydrogenation together with γ-butyrolactone in the liquid phase continuously-Hch is introduced into a liquid mixture of the anhydride in question and γ-butyrolactone and with an excess of hydrogen in the presence of a nickel-containing catalyst a temperature of 180 to 280 ⁰ C and under a pressure of 70 to 200 atmospheres and at the same time the hydrogenation product formed is withdrawn in gaseous form together with excess hydrogen from the reaction system, then condensed and from the liquid A. Part of y-butyrolactone is separated off, some of which is returned to the reaction vessel, while the tetrahydrofuran is separated off in the customary manner.