PROCESS FOR THE PRODUCTION OF ALDEHYDES

The preparation of aldehydes from olefins, oxide

of carbon and hydrogen in the presence of a catalyst, with formation of an aldehyde containing one more carbon atom than the olefin, is known (cf. J, Falbe, Synthesen with Kohlenmonoxyd, 1967, pages 3 and following). A catalyst favored for maintaining this reaction known in the industry as a "Oxo Synthesis" is cobalt, which can be used in various forms (cf. Falbe, loe. cit, pages 13 and following). However, it is also known that can be Oxo Process with other metals such as rhodium, ruthenium or iron (cf. Falbe, supra, pages 21 and following).

When is carried out with the cobalt, the active catalyst, which

is cobalt- hydrogénocarbonyle, is formed under the reaction conditions. In general, is carried out at temperatures of 100 to 200 °C in of the total pressure of 100 to 400 atmospheres.

Outside the aldehydes formed first, the reaction products contain considerable proportions of by-products due to side reactions or deeper, e.g. alcohols formed by hydrogenation of the aldehydes the first stage; is additionally present formic esters as well as high-boiling condensation of the aldehydes formed by first and other substances. A portion of the olefinic compounds used is also hydrogenated in the reaction products corresponding saturated.

In 1' hydroformylation of most of the olefinic raw materials (as far as they are not symmetrical and non-isomerizable by migration of the double bond, such as ethylene and cyclopentene for example), it occurs in the reaction conditions isomerisations complexes formed as intermediates from the olefinic compound and carbonyl, so that in general, are obtained reaction product mixtures Isomers.

Have previously been described one embodiment of the Oxo Process wherein catalysts used are complexes of certain phosphines, carbon oxide and transition metals such as cobalt, rhodium, etc (see German patents no. 1,186 455 and

1 212,953) _AOE280A2AO> In this known procedure, the reaction is carried out at pressures of 35 to 150 atmospheres and temperatures of to 200 °C l60. Starting from straight chain olefins, this method results in a ratio aldehydes normal/iso-aldehydes and a ratio normal alcohols/iso-alcohols in excess of those achieved by metal catalysts, in particular catalysts cobalt, without the addition of phosphine. Furthermore, in this method, proportions largest of the aldehydes formed by first are hydrogenated to alcohols. The undesirable formation of condensation products high-boiling is lessened, compared to the operating mode and having cobalt catalysts without: addition of phosphine,

However, in this embodiment of the Oxo Process, been encountered a disadvantage: generally, more than 10 fa olefinic compounds used are hydrogenated in saturated reaction products, especially based on a significant decrease in reaction rate. Therefore, the method requires of the reaction chambers for larger yields identical to those produced with-free phosphine.

Also mentioned the use of phosphites, to

instead of phosphine, apples as cocatalysts cobalt catalyst (cf, German patents no. 1,146 486 and 1,250 010), The addition of phosphites is decreased to a considerable extent the hydrogenation of the aldehydes Oxo formed by first to give the corresponding alcohols; however, the additions of phosphites markedly reduce reaction rates in the synthesis, compared to the operating mode and having cobalt catalysts containing neither phosphine, or phosphiteo

There are therefore a need for a method for transforming olefins, in the presence of catalysts containing additives Oxo as phosphorus compounds, to aldehydes, in high yields and avoiding, as much as possible a decrease in the reaction rate,

The invention has been found that can be prepared with very good results of ' aldehydes by reacting olefins with carbon monoxide and hydrogen at elevated temperature and pressure in the presence of catalysts containing transition metal from VlIIë sub-group of.. the Periodic Table when added to the catalyst a compound formed by reacting malonic diesters with compounds trivalent phosphorus containing at least 2 halogen atoms directly connected to the phosphorus atom and capable of reacting with active hydrogen atoms.

Additives for catalysts which results particularly advantageous, include the compounds of general formula:

where R ^, Rg, R^j R ^, R, -and Rg are radicals aliphatic, cyoloaliphatiques, heterocyclic or aromatic, substituted or unsubstituted, identical or different, ^ and A ' Ag are atoms same or different bridge and selected from the group consisting of oxygen, sulfur, nitrogen or phosphorus, n is a number equal to 0 or 1 and which may also take the value 2 when the bridge atom is sulfur, nitrogen or phosphorus.

In another embodiment of the method of the invention, are used as additives to the catalyst compounds of formulas' general:

wherein R ^, are radicals and aliphatic, cycloaliphatic, heterocyclic or aromatic, substituted or unsubstituted, same or different"

Utiliseravec can eneore satisfaction as additives to the catalyst compounds of the general formula:

where R ^ Rg are radicals and aliphatic, cycloaliphatic, heterocyclic or substituted or unsubstituted aromatic, same or different.

In Oxo Process conditions, catalysts containing a transition metal VTIIe sub-group of the periodic system-provide carbonyl compounds which, together with the phosphorus compounds used as additives in the invention are complexes more stable to heat and less volatile than the simple carbonyl metal compounds.

The additives for catalysts used according to the invention been implicated in the formation of aldehydes with higher selectivity. It has been found that the olefins hydrogenation carried out in saturated hydrocarbons was substantially completely removed, and that the deeper Oxo hydrogenation of aldehydes to alcohols occurring substantially no. Furthermore, comparison with known methods, the formation of condensation products high-boiling and other undesirable side products such as formic esters, is significantly reduced. This arrangement can also further increase the yield of aldehydes, in some cases, however, causes a reduction in the. conversion rate, by the addition of alkali hydroxides the catalyst system. Incidentally, the addition of a tertiary amine, optionally with an alkali hydroxide, may also lead to a further increase of the yield of aldehydes.

Note a feature important: the phosphorus compounds used as additives to catalysts in the invention do not affect or substantially no the speed of the hydroformylation reaction, as compared with the rate observed in 1' hydroformylation of olefins using the conventional catalysts free of additives, as the compounds of cobalfe -carbonyl. However, the phosphorus additives for catalysts used previously cause considerable reduction in the reaction rate and, therefore, the yield of valuable products per unit time for reactors of the same size.

The phosphorus compounds of the invention are used with particularly good results in combination with catalysts containing cobalt, rhodium, ruthenium or iron.

Listed below are examples of compounds for use as additives for catalysts according to the invention.

1. ) l-ethoxy-l, 2-diphenyl-^ 5', diphosphacyclopentène -2-one (5) - (~ 4J7-tricarboxylate (3.2.5) triethyl ;

2. ) l-ethoxy-l, 2-di-(4'-chloro-phenyl J- ZÎalphospha - eyclopentène -^ - ^ - ^-one jJ -tricarboxylate-C ^, ? ^) triethyl ;

2 ") l-ethoxy-L, 2-di-(4'-methyl-phenyl) - / T, 2- diphospha - cyolopentène -(5) - ( 4_ )-one 7"^{: aa rboxylate br l}-triethyl-( 2j2j5 );

4. ) l-ethoxy-l, 2-di ~ (4'-dimethylamino-phenyl) - / Î, 2- diphosphacyclopentène ~ ane-(5) - (4) - - 7-tricarboxylate (3.3.5) triethyl;

5 =) l-ethoxy-l, dl-2 - (4 '- fluopo -phenyl)_{-i Æ}' , 2 " dlphospha -cyclopentene-(5)-one * - (4J7" '-tricarboxylate ( 5j5j5 ) triethyl;

6. ) l-ethoxy-l, 2" di-(2^{, -} tert. -butyl-phenoxy)-_J/ T, 2" diphosphacyclopentène -(5) - --one (4J7-t^{; rlcarboxylate}-(3.3. > 5) triethyl j

7. ) l-ethoxy-l, 2-di-(2 ', 5' -dimethyl-phenyl) - / r, 2, - diphosphacyclopentène -one (5) - (-tricarboxylate 4J7 - (5.5 > 5) triethyl;

8. ) l-ethoxy-l, 2-di-(~ N methyl-anilino) - / r, - diphosphaeyclopentène -2-one (5) - ( 4_ ]^{_ 7-tricarboxylate} (5 > 5 > 5) triethyl ;

9 ") l-methoxy-l, 2-diphenyl-/ T, (5) 2- diphosphacyclopentène -one-(4j7"-tricarboxylate (3.3.5) triraéthyle of j

10. ) l-tert. " Butoxy-l, 2-diphenyl-_J/ eroism ', - diphosphaeyclopentène -2-one (5)-(> 7-tricarboxylate 4j-(3.3.5) tri-tert. -butyl;

11. ) l-tert. -butoxy-l, 2-di-(4'-dimethylamino-phenyl)/ Î, 2- diphosphacyclopentène -(5)-one-( 4_ } - 7-tricarboxylate (3.3.5) tri-tert. -butyl;

12. ) l-ethoxy-l, 2-di-n-butyl-./ r, - diphosphacyclopentène 2-one (5) - (> 7-4J-tricarboxylate (3.3*5) triethyl.

The preparation of the 1,2- diphosphacyclopentène -one-(5) - (4) listed above s! produced for example by reacting malonic diester with d. is trivalent phosphorus compounds containing at least 2 halogen atoms directly connected to the phosphorus atom and capable of reacting with hydrogen} the reaction is carried out in the presence of a base, for example of a tertiary amine, for continuously removing the hydrohalic acid formed in the reaction. The reaction is carried out at room temperature or slightly above. Operate is preferably between 40 and 60 °C. In particular instances, for example in the case of reagents being empêchenemts steric, it can be brought to be observed at higher temperatures.

The catalysts are used to the standard amounts for Oxo Process. Therefore, for example, cobalt and ruthenium are used at a concentration of about 0.01 to 5 preferably 0.1 to 15 % by weight of metal with respect to the olefin compound, implemented. Rhodium is usually used at a concentration of 0.00001 to 0.5 #, preferably 0,001 to 0.1 $by weight of metal, relative to the olefin compound. The atomic ratio of metal to phosphorus is generally 1: 0.5 to 1:10, preferably from 1: 0.5 to 1:3. However, can be observed atomic ratios metal/phosphorus located above or below the range of values indicated"

The method of the invention is advantageously carried out at pressures of 50 to 400 atmospheres, preferably 50 to 300 atmospheres, by maintaining a molar ratio of hydrogen/oxide carbcne of 1 s 5 s 1 to 5, preferably 1 s 1. The reaction temperature ranges between 70 and 250 °C, preferably between 90 and l8o °C. It should be noted in this regard that the yield of aldehydes depends on the temperature. When the reaction temperature decreases, increases the proportion of aldehydes in the reaction product, relative to the olefin implementation. Simultaneously But is observed a decrease in the reaction rate. The operation at low temperature is especially advantageous when it is desired to transforming olefins having unbranched reaction products.

The reaction of the olefins with carbon monoxide and hydrogen according to the invention can be carried out optionally in the presence of an inert solvent or diluent.. When is carried out in the presence of solvent, it is for example aliphatic hydrocarbons, cycloaliphatic or aromatic, , ethers, esters, ketones, or the reaction product itself or certain parts of the reaction product, for example the bottoms. Hexane, the oetane, cyclohexane, benzene, toluene, xylene, 1' diphenyl ether, tetrahydrofuran or mixtures of these substances may be used with satisfaction as solvents..

The reaction may be carried out batchwise but operate continuously. Due to the remarkable stability to heat and low volatility complexes which form in the reaction mixture from the compounds of métauxcarbonyle and phosphorus compounds, the reaction product can be cleaned of simple * maMere of the catalyst by distillation of * is operated. allowing the catalyst-in the base and recycle in liquid phase, optionally-after replacement to low losses with fresh catalyst.

The following examples illustrate the invention without however limiting ^ in these examples, the indications of parts and percent, extend by weight unless otherwise specified.

In the examples 1 to 18, has been described 1' discontinuous hydroformylation of olefins in accordance with invention¹ 1 ; in the examples 1 to 17, the reactions are carried out in the presence of catalysts cobalt; in the example 18, a rhodium catalyst is used. The continuous hydroformylation 1 is described in the examples 19-and 20.

Examples 1 to 17 :

In an autoclave stainless steel V4 A of 2.1 litres

to vertical magnetic stirring, is placed in each case 300 g of benzene, 3.45 g of dicobalt octacarbonyl- octaearbonyle and, except in the example 1 which is a comparative example, the phosphorus-containing cocatalysts indicated in the following table; optionally, also introduces the caustic potash. The phosphorus compound is used at corresponding to the reporter ' atomic Go:P = 1: 1.1.

Is heated the content of the autoclave in the presence of CO and Hg in the ratio of 1:1, under a pressure of 250 atmospheres, at the temperature indicated in the table. Using a metering pump that displaces under pressure, is then introduced g 150-hexene (l). The synthesis gas consumed in the reaction is continuously replaced by a device for automatically adjusting the pressure preventing a decrease of pressure in the autoclave. Is controlled course of the reaction by regular samples of samples and analysis by gas chromatography. Once the reaction is complete, drain is autoclavable, and determines the composition of the reaction product by vacuum distillation and analysis by gas chromatography.

The results of the operations are reported in the table appended, wherein the phosphorus compounds used as additives to catalysts are designated by numbers corresponding to those of the particular compounds given in examples? in the description above.

EroismExample 18

In an autoclave stainless steel V4 A of 4 litres, to vertical magnetic stirring, 800 g of toluene is placed, 0.4 g of rhodium (in the form of 2-ethylhexanoate} and 0.2 g of l-ethoxy -1,2-diphenyl-^ T, 2- diphosphacyclopentène -(5) "One-(4J7" tbicarboxylate -(3.3*5) triethyl and is heated to 170 °C CO Hg in the presence of and in a ratio of 1:1 under a pressure of 250 atmospheres. Is introduced into the autoclave using a metering pump réfoulant 40C pressure > g-hexene (l). The synthesis gas consumed in the reaction is continuously replaced by a automatic pressure regulating preventing any drop of pressure in the autoclave. The course of the reaction is controlled by regular éclhantillons samples and analysis by gas chromatography. After a period of 2 réactiorr -h, is emptied the autoclave and determines the composition of the reaction product by vacuum distillation and analysis by gas chromatography. More than 95 % hexene-(l) are reacted in the form of net i-heptanal.

Examples 19 and 20 Illustrent continual 1' hydroformylation according to the invention, which hydroformylation is carried out in the apparatus described below, with reference to the drawing of the attached drawing single^

In a reactor 4, the conduits 1,2 and 3 respectively make the olefin, the synthesis gas 1 television) and the catalyst. The reaction products leave the reactor through a conduit 5 and arrive at the foot 7 of a distillation column 6. The distilled fractions of the reaction product is sent through a condenser 8 in a separator 9 and " thence, recycled by a pump 10 in head 11 of the column 6 12 or discharged. At the base 7 of the column 6, the hydroformylation catalyst remains in the high boiling point of the reaction product. It is returned to the reactor 4 via a pump 13. A conduit 16 serves to bring the fresh catalyst. Waste gas that escape the distillation column 6 are expanded by a conduit 17 or returned at the base of the column 7 by a ' recycle pump 14. Throughout the operation., the level of liquid in the bottom of column 7^is kept constant by continuous sample of the product base through the duct 15.

Example 19 :

In the reactor 4, is reacted, time, propylene 3.5 kg of commerce (which corresponds to a mean residence time of 45 minutes y l60 °C, under a pressure of 240 atmospheres, with carbon oxide and hydrogen (in the ratio 1 ; l) in the presence of dicobalt octacarbonyl- cctacarbonyle and l-ethoxy-l, 2 (diphenyl ^ l, - diphosphacylopentène -2-one (5) - (4j7 "-tricarboxylate (3.3.5) triethyl. Cobalt/phosphorus The atomic ratio in the catalyst system is s 1*, 1 1. The catalyst-is dissolved in the fractions to ftàut boiling point of the reaction product (to the concentration of 4.1 g/liter) and recycled to the flow rate of 9 liters of solution · time " The complement of fresh catalyst required is 0.0 > % C &, relative to the propylene carried out. The crude hydroformylation product is fractionated in the distillation column 6 at a temperature base I56°C, a distillation pressure of 10 atmospheres, and a gas recirculation normal 13. As a reaction product about 5 kg/hr of a distillate that has the composition below:

aldehydes: 90.8#

formic esters: ^ 0,4 %

alcohols: 4.0 %

high

boiling

4,8