CS212295B2 - Method of making the butyraldehydes - Google Patents

Abstract

1440413 Butyraldehydes (oxo process) MITSUBISHI CHEMICAL INDUSTRIES Ltd 17 Sept 1974 [21 Sept 1973] 40567/74 Heading C2C A process for producing butyraldehydes comprises reacting propylene with a water gas in a reaction solvent containing a triarylphosphine and a soluble rhodium complex in which a portion of said triarylphosphine is co-ordinated with rhodium metal, under a carbon monoxidehydrogen total pressure of from 30 to 100 kg./cm.<SP>2</SP> and at a temperature of from 60‹ to 150‹ C., the total amount of said triarylphosphine present in said reaction solvent and in said soluble rhodium complex co-ordinated with rhodium metal being from 1 to 30 m. moles per litre of said reaction solvent. The soluble rhodium complex may be present at a concentration of from 0À1 to 500 mg., calculated as rhodium metal, per litre of said reaction solvent, and the ratio of triarylphosphine to rhodium may be 5 to 200 moles per gram-atom, and the water gas may contain <SP>1</SP>/ 3 to 7 moles of hydrogen per mole of carbon monoxide.

Description

The present invention relates to a process for the preparation of butyraldehydes which are rich in straight-chain isomers and which consists in hydroformylating propylene in the presence of a rhodium-triarylphosphine complex catalyst.

The hydroformylation reactions of olefins using rhodium as a catalyst have been extensively investigated since it was found that rhodium as a catalyst has a high catalytic ability and a high selectivity, particularly in the production of aldehydes by the hydroformylation reaction of olefins. In particular, rhodium complex compound catalysts in which biphylic ligands, such as tertiary phosphines, are coordinated with metal rhodium, appear to be advantageous in the hydroformylation of alpha-olefins, since catalysts of this type exhibit high selectivity for straight chain aldehydes. These aldehydes are preferable to branched chain aldehydes. The hydroformylation reactions in which these catalysts are used can be carried out at a lower pressure than that used in conventional hydroformylation reactions. Upon addition, these catalysts can be recovered for their high stability by separating the reaction products into aldehydes and the reaction solvent containing the catalyst, a rhodium-tertiary phosphine complex. This separation is carried out by distillation and the reaction solvent obtained which contains the catalyst is returned to the reactor for further hydroformylation.

An example of the prior art is Japanese Published Patent Application No. 10729/1970, describing a method using an excess of organophosphorus compounds in hydroformylating olefins in the presence of a soluble rhodium catalyst complex in which the tertiary organophosphorus component is Experience shows that the use of any excess organophosphorus compound serves to maintain high catalytic capability and improve selectivity for straight chain aldehydes.

Also, U.S. Pat. No. 3,527,809 discloses a method for hydroformylating alpha-olefins at low pressure in the presence of a rhodium complex catalyst in which biphylic ligands having a ΔHNP value of less than 425 are coordinated with metallic rhodium. As shown in Example 76 of this United States Patent, the molar ratio of straight chain to branched isomer of the aldehydes produced can be 30: 1 in hydroformylation of 1-hexene, at a water gas pressure ranging from 620 kPa to 826 kPa , in the presence of a rhodium-triphenylphosphine complex catalyst.

Rhodium as a catalyst has been used previously when various ligand studies have been performed in a hydroformylation reaction under reduced pressure. However, the relationship between reaction pressure and selectivity for straight chain aldehydes has not been investigated in detail. The above-mentioned U.S. Patent No. 3,527,809 and J. Chem. Soc. (A), pp. 3,133-3,142 (1968), suggest that the lower the water gas pressure, the higher the selectivity for straight chain aldehydes.

Taking into account the relationship between water pressure and selectivity for straight chain aldehydes, as well as the rhodium complex property (i.e., catalyst stability at low water pressure), hydroformylation reactions using the rhodium organophosphorus complex as catalyst. are carried out at relatively low pressure. Reactions carried out ^with Ac ^{nus s} pressure samples are etonom m ^ W also from that ^{reason that} the cartridge and d ^{kl y} ^ furnished for measurement and operations are low. _ч

As a result of this study, it was found that the relationship between reaction pressure and selectivity for straight chain isomers in hydroformylation of propylene has not yet been found. Research has found that in the hydroformylation of propylene in the presence of a rhodium complex catalyst in which triarylphosphine is coordinated with metal rhodium (hereinafter referred to as rhodium-triarylphosphine complex), the selectivity for straight chain aldehydes depends greatly on the phosphine concentration in the reaction solution; at the water gas pressure. In the present invention it has been found that at low concentrations of phosphine ratio of the normal forms of the isoforms produced ^b u ^t yra ^l de ^H y ^d u ^(D and ^L e is the ratio judicious ^d en as n ^/ i ratio) in ^YK azuje maxi. it measures the value at the water gas pressure in a certain area. The catalyst solution containing the rhodium-tertiary foefin complex is separated from the reaction products and returned to the reactor for reuse. The catalyst, which is deactivated in proportion to the amount of reaction inhibitors contained in the crude propylene and water gas, accumulates in the catalyst solution. Due to the inactivated deactivated catalyst, it is necessary to remove a portion of the catalyst solution and replace it with fresh in order to maintain a constant catalytic efficiency. In other words, ^LeVeLs Community rhodium phosphine lost it in odatoanova ^é ^ ^CA with ^those returning to ^the ATA ^AT oru ^Ly is greater, the higher the concentration of rhodium and a tertiary phosphine. Therefore, it is advantageous to carry out the reaction at a concentration of rhodium and phosphine so low as to still achieve high selectivity for n-butyraldehyde.

It is an object of the present invention to provide a process for the preparation of butyraldehydes in which a product rich in straight chain isomers is obtained, with losses of phosphine and rhodium being minimal.

The process according to the invention for the preparation of butyraldehydes is characterized in that:. reacting continuously the reaction solvent comprising triphenylphosphine and a soluble rhodium complex in which a portion of said triphenylphosphine is coordinated with the metal rhodium, propylene, carbon monoxide and hydrogen in a ratio of 1/3 mole to 7 moles of hydrogen per mole ^; en ^eh tysMihku about ^l to ^the UHE ^him to REA ^CZK n ^{i 'F} crosslinked with zones kept at ^{t s} e lo ^{p p I s} ohybujíc in rozmez.í 60 ^{d 1} 5 ° ^C and ^at celtavém tlat ^alkyl sli ^No n ^CART in ^teh coal-OA in the UV range ^{thanks I} - from 2.94 ^Mp and 9.8 ^{d 1} and ^Mp ^ ^d estilován ^r m ^t, and ^to the MMN ^{Ikle CZK} rea n ^and mixtures of ^d from ^AD ene reaction ^d zcSny for the ^DdeI en ^d of butyraldehyde as a distillate and the formation of a distillation residue which comprises a soluble ^to om ^p lex rho ^di aa triphenylphosphine ^LF axis ^f in ^to esters is recycled, ^d for rea ^{CZK nus} of ^O N ^ ^p Rice extended ^{f p t} Nu US rhodium complex is present in a concentration ranging from 5 to 100 mg, calculated as rhodium metal per 1 dm ^ ^ re and ^CZK the ^H on the solution ^ u ^ M! ^ ^p om ^e r toifenylfosftau and metal ^é it r ^h o ^d i ^{a, kt} ns form soluble complexes of rhodium in the reaction solvent - ranging from 5 to 200 moles of triphenylphosphine per mole of rhodium metal and the total amount of triphenyl phosphine which is present in the reaction solvent in a soluble rhodium complex in coordination with the metal rho ^d IEM bends with ^p in the range of ^{d 1 d d} 3 ^{0 1} -mmolů dm ^ REA ^CZK dissolves whom you ^ddl a.

An advantage of the process according to the invention is that the hydroformylation reaction of propylene, which is within the scope of the invention, reduces the losses of rhodium and phosphine and the addition product is butyraldehydes which contain a large proportion of n-butyraldehydes. From an industrial point of view, this process is very advantageous.

The process for the preparation of butyraldehydes according to the invention consists, as already mentioned, in the hydroformylation reaction of propylene in a reaction solvent containing a low phosphine concentration. This principle will be explained in more detail below.

The catalyst used in the hydroformylation of the present invention is a rhodium-triarylphosphine complex. The most commonly used phosphine ligand is triphenylphosphine, but other phosphines having lower alkyl groups, such as a methyl group on the phenyl group, may also be used. The catalyst may be a complex comprising rhodium and phosphine prepared by various conventional methods such as, for example, a hydrocarbonyl-tria- (triphenylphosphine) rhodium complex. The catalyst may be prepared simply and preferably on an industrial scale by dissolving readily available rhodium compounds, for example organic or inorganic salts of rhodium such as acetate, nitrate or rhodium sulfate, in a suitable solvent such as water, organic acids (e.g. acetic acid), alcohols ( such as methanol) and esters (such as gamma-butyrolactone) and the like. The introduction of this solution into the hydroformylation reaction reactor forms a complex by reaction with triphenylphosphine, which is also present in the reactor.

Although the exact form of the rhodiumtrialrylphosphine complex that is active in the hydroformylation reaction is not entirely obvious, the catalyst is considered to be a complex in which phosphine, carbon monoxide, olefin and hydrogen are in coordination with rhodium. In this case, the active complex does not exist in definite form, but appears as a complex in which different components are present, having different ligeoids corresponding to each other and where equilibrium varies with the concentration of each ligid.

Phosphis works towards increasing the stability of the complex in coordination with rhodium · In order to obtain a catalyst that has sufficient stability and can therefore be recycled into the cycle for further use, it is desirable that more than 5 moles, usually 5 to 200 moles of phosphine, per 1 mol of rhodium. In general, the value of S / I ratio increases with stoupaaíeí phosphine concentrations and therefore it is advantageous from the viewpoint of high selectivity for n-butyraldetyd _w taking a high concentration of phosphine. However, the use of such a high phosphine concentration is not advantageous from a very small point of view, since the loss of phosphine on the recovering catalyst solution also rises, it is not necessary to remove part of the solution and replace it with a fresh catalyst solution. by-products of high-boiling reaction products. In the process it is very difficult to separate the dropped catalyst solution which contains a large amount of phosphine and to obtain only the phosphine which contains the products with high boiling point. For the above reasons, it is highly desirable to increase the selectivity for n-butyraldehyde at the lowest possible phosphine contentation for carrying out the hydroformrylation reaction on an industrial scale.

Investigation of the hydroformylation reactions of propylene, in which the sulfur complex is used as a catalyst, has shown that the ratio of the butyraidedehydes produced in different ways (as will be discussed below) depends on the water gas pressure and the phosphine comment. In the following description, the phosphine and rhodium concentrations are calculated at 20 ° C and the atmospheric pressure.

That is, at a phosphine concentration below about 30 µmoy per liter of reaction solvent, the ratio rises to a maximum when the hydroformylation reaction is carried out at the pressure of the carbon monoxide / hydrogen mixture (hereinafter referred to as the extra water gas pressure). in the range of 2.94 MPa to 9.81 MPa. At a water gas pressure lower than 100 psig or more than 100 psig, the ratio s / i decreases. At a concentration of affine in the range of from 30 to 50 millimoles per liter of reaction solvent, the ratio is substantially constant, at a lower pressure than 9.81, when the ratio s / i is already practicable. With a phosphate strain greater than 50 millimoles per liter of action solvent, the ratio increases when the partial pressure of the water gas is simultaneously reduced, which is in line with the above conclusions.

and

The drawing shows a graph showing the relationship between. pareial water gas pressure (values plotted on the x-axis in MPa) and i / butyraidedehyde ratio (test ratio is indicated by o-y axis), produced by hydroformylation reaction at a rhodium concentration of 10 milligrams (calculated on rhodium metal), and a liter of toluene The reaction was carried out at a reaction temperature of 120 ° C and at various concentrations of thiifecyifts. Individual curves 1, 2, X and £ results obtained by hydroformylation at concentrations of 100 µmol (curve j), 30 millimoles (curve)), 10 µmimoy (curve J) and 1 militaol (curve 1) per liter of toluene.

According to the invention is Hydroform ^r laee carried out preferably at a concentration of FOS ^ ou less than 30 millimoles, but greater than 1 millimole per liter reakčoího rozpoltě <DLA, the arrangement being such that zajišluje stabblitu k ^ MPE-Siho catalyst is proportionate to its eirkulaei and at a water gas pareial pressure in the range of 2,94 MPa to 9,81 MPa.

In the process for the preparation of the butyraidedehydes of the present invention, the rhodium concentration in the catalyst solution affects the reaction ratio, but cannot be a factor that can be varied with the product ratio. Thus, the rhodium concentration is determined by both factors: that is, the improved reaction ratio that is obtained by the increased rhodium concentration and, on the other hand, the catalyst that needs to be added to the reaction system. In principle, the rhodium concentration ranges from 0.1 to 500 milligrams, but is preferably from 5 to 100 milligrams per liter of reaction solvent (calculated on rhodium metal).

The reaction rate increases with increasing temperature, as is generally known for chemical reactions. However, the n / i ratio decreases somewhat at high temperature, thereby reducing the yield of the desired butyraldehydes. The most common reaction temperature ranges from 60 to 150 ° C.

Suitable solvents that can be used in the hydroformylation of the present invention are those that have a boiling point above butyraldehydes (i.e., above about 75 ° C at 100 psig) and that are inert. These solvents can be reused in the reaction and the catalyst contained therein is continuously recirculated to the reaction system, after prior separation of the reaction products by distillation. Examples of such solvents are aromatic hydrocarbons such as toluene, xylene and the like, further saturated aliphatic hydrocarbons such as decane, tetradecane, octadecane and the like, or esters such as butyl acetate, butyrolactone, or alcohols such as butanol, 2-ethylhexanol etc. In some cases, butyraldehyde can also be used as the reaction solvent.

The molar ratio of hydrogen to carbon monoxide in the water gas used in the production is not critical. This water gas consists of about 1/3 mole to 7 moles of hydrogen per mole of carbon monoxide.

The process according to the invention will be further illustrated by the following non-limiting examples.

Unless otherwise indicated, all percentages, parts, ratios, etc. are by weight.

Examples

Basic operating procedure for the examples and comparative examples

A 200 ml autoclave equipped with a magnetic stirrer was charged with 50 ml of toluene and a predetermined amount of triphenylphosphine and rhodium-acetate. The autoclave was purged with argon and 250 millimoles of propylene was added. The temperature in the autoclave was set to a predetermined value and the reaction was initiated by introducing a mixture of carbon monoxide and hydrogen gases (molar ratio of hydrogen to carbon monoxide of 1.17) at a preselected pressure. In order to replenish the consumed gas in the reaction, a gas mixture having the same molar ratio was supplied from the gas bomb connected to the autoclave during the reaction via a gas pressure maintaining device in the autoclave. When gas consumption ceased, which was considered an indicator of complete reaction, the autoclave was cooled and the gas and liquid phases were subjected to gas chromatography analysis to determine the amount of propylene remaining unreacted and the amount of autyraldehyde produced. The results obtained in each case showed that the conversion of propylene was more than 99% and the selectivity of butyraldehydes was more than 98%.

In the following examples and comparative examples, the pressure is referred to as total pressure '. Since the water gas partial pressure cannot be defined independently because the partial pressure varies with the reaction temperature, propylene concentration and propylene conversion, the following table 1 shows the relationship between the total water gas pressure under the reaction conditions used in the examples and the comparative examples.

Table 1

Reaction temperature (° C) Total pressure (MPa) Partial at the start of the reaction water gas pressure (MPa) at the end of the reaction 120 2,0 0.4 >, 9 120 5.0 3.4 4.9 120 Л5 5.9 7.4 120 10.0 8.4 9.9 120 12.0 10.4 11.9 120 16.0 14.4 > 5,9 120 20.0 18.4 19.9 90 2,0 0.8 2,0 90 5.0 3.8 5.0 90 7.5 6.3 7.5

Solvent: toluene Initial propylene concentration: ~ mol / liter toluene.

Example 1 a d 1 to 7

The procedure was the same as the basic procedure outlined above, using 10 milligrams of rhodium per liter of toluene (calculated on rhodium metal). The reaction conditions used in these examples and the n / i ratio of the resulting butyraldehydes are shown in Table 2 below.

Table 2

Example # Total pressure (MPa) Reaction temperature (° C) Triphenylphosphine concentration (mmol / liter toluene) n / i ratio 1 5.0 120 10 1.79 2 7.5 120 1 1 66 3 7.5 120 10 1, 80 4 7.5 120 30 1.83 5 10.0 120 10 1.78 6 5.0 120 1 1, 50 7 5.0 90 10 2.04

Comparable results to those in Table 2 can also be obtained when the reaction is carried out using the recovered catalyst contained in the toluene solution obtained by distillation from the resulting butyraldehyde mixture. In this case, the reaction is carried out in a continuous manner.

Comparative examples

Examples 1 to 10

The procedures in the Comparative Examples were the same as in the basic procedure, using rhodium at a concentration of 10 milligrams per liter of toluene, triphenylphosphine at a concentration of 1 to 30 millimoles per liter of toluene, at a total pressure of less than 2.94 MPa or greater. than 9.81 MPa. The results are shown in Table 3 below.

Table 3

Comparative example no. Total pressure (MPa) Reaction temperature ( ^ý C) Triphenylphosphine concentration (mmol / liter toluene) n / 1 ratio 1 2,0 120 1 1.16 2 2,0 120 10 1.47 3 2,0 120 20 May 1, 64 4 2,0 120 30 1, 79 5 12.0 120 1 1.53 6 12.0 120 10 1.73 7 12.0 120 30 1.81 8 16.0 120 1 1.47 9 20.0 120 1 1.38 10 2,0 90 10 ', 91

Examples 11 to 14

The comparative examples were the same as in the above basic procedure, using rhodium at a concentration of 10 milligrams per liter of toluene, and triphenylphosphine at a concentration greater than 50 millimoles per liter of toluene. The reaction conditions used in these Comparative Examples and the results obtained are shown in Table 4 below.

Table 4

Comparative example no. Total pressure (MPa) Reaction temperature 1 ° C) Triphenylphosphine concentration (mmol / liter toluene) n / i ratio 11 2,0 120 100 ALIGN! 2.22 12 2,0 120 50 1.94 13 5.0 120 100 ALIGN! 1> 96 14 7.5 120 100 ALIGN! 1, 95

Examples 15 to 18

The procedure used in these Comparative Examples was the same as that described in the basic procedure above, using rhodium at a concentration of 100 milligrams per liter of toluene (calculated on rhodium metal) and a reaction temperature of 90 ° C. The reaction conditions used in these Comparative Examples and the results obtained are shown in Table 5 below.

Table 5

Comparative example no. Total pressure (MPa) Reaction temperature ⁽ ° C) Triphenylphosphine concentration (mol / liter toluene) n / i ratio 15 Dec 2,0 90 100 ALIGN! 2.45 16 5.0 90 100 ALIGN! 2.04 17 7.5 90 100 ALIGN! 1.96 18 2,0 90 10 1.87

Examples 19 to 20

In the Comparative Examples, the same procedure was used as in the basic process, using triphenylphosphite instead of triphenylphosphine. The reaction conditions used in these Comparative Examples and the results obtained are shown in Table 6 below.

Table 6

Comparative example no. Total pressure (MPa) Reaction temperature (° C) Triphenylphosphite concentration (mol / liter toluene) n / i ratio 19 Dec 2,0 120 10 1.76 20 May 5.0 120 10 1.60

Examples 21 to 23

In the comparative examples, the same procedure as in the basic process ¹ , using 1-hexene as crude olefin instead of propylene, was used in an amount of 2.5 moles per liter of reaction solvent, and benzene instead of toluene was used as of a reaction solvent. The reaction conditions used in these examples and the results obtained are shown in Table 7 below.

Table 7

Comparative example no. Total pressure (MPa) Reaction temperature (° C) Triphenylphosphine concentration (rnol / liter of reaction solvent) n / i ratio 21 1 o; o 110 3 1.18 22nd 5.0 110 3 2.66 23 3.0 110 3 2.68

In the above text and in the examples, the process according to the invention was carried out. described in detail with reference to specific. However, it is obvious that various alternative variations of the process can be made without departing from the scope of the invention.

Claims (1)

SUBJECT OF THE INVENTION A process for the preparation of butyraldehydes, characterized in that a reaction solvent comprising triphenylphosphine and a soluble rhodium complex in which a portion of said triphenylphosphine is coordinated with metal rhodium, propylene, carbon monoxide and hydrogen in a ratio of 1: 3 to 7 moles of hydrogen per mole of carbon monoxide in a reaction zone maintained ^F crosslinked with ^é te ^p Lot ^{E =} OH ^yb UJ ^I C ^s in the range of ^d 60 ^d 150 ° C and ^p s ce ^o b ^s m QAKU CO and hydrogen ranging from 2.94 MPa to 9.31 MPa, distilling the resulting reaction mixture ^of a branch ^ADE n ^s of the reactions of ^O N ^y is the ^{DdeI b} fag out ^{hy ld} e d in ^{f y} ^ Orme stll UAZ ^b ^ ^í ývajíc desti.lační moiety which contains a soluble rhodium complex and triphenylphosphine is fed back to the reaction of ^O N ^{y, PRICE} EMZ oral extended ^{p to} r om ^pl ex ^h of ^di and ^argue Omen ^to oncentrac ⁱⁿ the range of ^{d 5 d} about 100 m ^and ligram ^s, based on ^the ovové rho ^d ium on 1 dm ^ ^ REA ntao extended ^p ou ^{te dL} and ^{p E} r om ^{trifluroacetic} en ^yl phosphine and rhodium metal which forms a 'soluble complex of rhodium in the reaction solvent. . ranges from 5 to 200 moles of triphenylphosphine per mole of rhodium metal and the total amount of triphenyl phosphine which is present in the reaction solvent in a soluble rhodium complex in coordination with the metal rhodium ranges from 1 to 30 millimoles per ^{1 d} m ^ Hand rea ^{for larger-span} t and ^EDL.