MXPA97002285A - Process for preparing 1,3-alcanodioles y3-hidroxialdehi - Google Patents

Abstract

The present invention relates to a process for preparing 1,3-alkanediols and 3-hydroxyaldehydes by hydroformylating an oxirane with carbon monoxide and hydrogen in the presence of one or more hydroformylation catalysts based on group VIII metal, which may contain up to 50 mol% based on the metal of the phosphine modified catalyst, wherein the concentration of the oxirane at the start of the reaction is less than 15% by weight, based on the weight of the total liquid reaction mixture. The process allows the production of 1,3-propanediol in yields and high selectivity

Description

DESCRIPTION OF THE mV? NCICN This invention relates to a process for preparing 1,3-alkanediols and 3-hydroxyaldehydes by formylation of an oxirane (1, 2-epoxide). In particular, the invention relates to a process for preparing 1,3-propanediol by hydroformylation of ethylene oxide in the presence of a hydroformylation catalyst based on group VIII and hydrogenation of the hydroformylation product. The preparation of 1,3-propanediols similar to 1,3-propanediol (PDO) is described in US-A-3 687 981. The process comprises the hydroformylation of an oxirane such as ethylene oxide, in a concentration of more than 15 percent by weight based on the total liquid reaction mixture, in the presence of a metal carbonyl catalyst containing a group VIII metal, followed by hydrogenation of the hydroformylation product. The hydroimilation product of that process is a cyclic hemiacetal dimer of 3-hydroxypropanal (HPA), ie, 2- (2-hydroxyethyl) -4-hydroxy-1,3-dioxane. The PDO compound is from REP: 24305 particular interest as an intermediary in the production of polyesters for fibers and films. Despite the publication of this patent in 1972, fiber-grade polyesters based on PDO to date have not been commercially available. The separation of the catalyst from the cyclic hemiacetal produced, in US-A-3 687 981, in phase separation, is complicated and inadequate. As a result, the cost of preparing polymer-grade PDOs is too high. In US-A-3 456 017 and US-A-3 463 819 1,3-alkanediols are prepared directly with only minor amounts of the intermediate hydroformylation product in the presence of certain phosphine-modified cobalt carbonyl catalysts. The commercialization of the process of these North American patents is discarded, due to the excessive quantities of catalyst used in them. In addition, in WO 94/18149, phosphine-modified cobalt carbonyl catalysts are used. They are used in a much smaller quantity than in the North American patents, which mainly produces 3-hydroxyaldehyde. Although the activity of the phosphine-modified cobalt carbonyl catalyst described in the international application is high, improvements remain desirable, particularly in view of the undesirable co-production of acetaldehyde. In addition, the cost of phosphines, which is notoriously difficult to retain when the catalyst is reused or recycled, adversely affects the economics of that process. It would be desirable to prepare 3-hydroxyaldehydes and 1,3-alkanediols selectively and inexpensively. Therefore, it is an object of the invention to provide an economical process for the preparation of 3-hydroxyaldehydes and 1,3-alkanediols in the presence of a hydroformylation catalyst, which process allows convenient reuse of the catalyst. Accordingly, the invention provides a process for preparing 1,3-alkanediols and 3-hydroxyaldehydes by hydroformylating an oxirane with carbon monoxide and hydrogen in the presence of one or more hydroformylation catalysts based on group VIII metal, which may contain up to 50 mol% based on the metal of the phosphine modified catalyst, and in the presence of an organic solvent, in which the concentration of the oxirane at the start of the reaction is less than 15 weight percent (% by weight) based on the weight of the total liquid reaction mixture. Preferably, the reaction is carried out at a temperature below 100 ° C. As a result, a mixture of intermediate product is obtained, consisting essentially of initial components and 3-hydroxyaldehyde, the latter in an amount that is less than 15% by weight, based on the total liquid reaction mixture. At this concentration, the selectivity towards 3-hydroxyaldehyde is high, while the catalyst can be conveniently reused. The oxirane comprises an organic compound, two carbon atoms of which are connected by an oxy bond, as well as by means of a single carbon-carbon bond. Generally speaking, the oxiranes comprise hydrocarbyl-epoxides having at least 2, preferably up to 30, more preferably up to 20, more preferably up to 10, carbon atoms. The hydrocarbyl group can be aryl, alkyl, alkenyl, aralkyl, cycloalkyl or even alkylene; linear chain or branched chain. Suitable examples of oxirates include 1,2-epoxy (cyclo) alkanes, such as ethylene oxide, propylene oxide, 1,2-epoxy octane, 1,2-epoxycyclohexane, 1,2-epoxy-2, 4, -trimethylhexane and the like, and 1,2-epoxyalkenes such as l, 2-epoxy-4-pentene and the like. Ethylene oxide and prcpylene oxide are preferred. In view of the demand for PDO, the ethylene oxide (EO) is the oxirane most preferably used in the process of the invention. The hydroformylation reaction is carried out in a liquid solvent inert to the reactants and products, ie, that is not consumed during the reaction. At the end of the reaction, the liquid solvent facilitates the separation of the hydroformylation product. The separation can be carried out by allowing the product to form a separate layer, as described in US-A-3 687 981. However, as discussed in the following, it is preferred to carry the separation by extraction with a aqueous liquid. In general, the ideal solvents for the hydro-alumilation process (a) will show a low to moderate polarity of mar.ra that the 3-hydroxyaldehyde will dissolve until a concentration of at least about 5% by weight under hydroformylation conditions, while a significant amount of solvent remains as a separate phase in the extraction process with the aqueous liquid, (b) it will dissolve carbon monoxide, and (c) it will essentially be immiscible in water. By essentially "not miscible in water" it is meant that the solvent has a solubility in water at 25 ° C of less than 25% by weight so as to form a hydrocarbon-rich phase separated by extraction of the -hydroxyaldehyde from the reaction mixture. of hydroformylation. Preferably, this solubility is less than 10% by weight, more preferably less than 5% by weight. The solubility of carbon monoxide in the selected solvent will generally be greater than 0.15 v / v (1 atm, 25 ° C), preferably greater than 0.25 v / v, expressed in terms of Ostwald coefficients.

The preferred class of solvents are alcohols and ethers which can be described according to the formula (1) r 1 2 R-0-R wherein R1 is selected from hydrogen, a linear or branched cycloalkyl or aromatic C1-20 hydrocarbyl, or monoalkylene oxide or polyalkylene oxide, and R2 is selected from a straight or branched cyclic or aromatic hydrocarbyl group. , alkoxy or monoalkylene oxide or polyalkylene oxide, or Rx, R2 and O together, form a cyclic ether. The most preferred hydroformylation solvents can be described by the formula (2) RJ R-C-O-R1 (2) i5 wherein R1 is selected from hydrogen or a hydrocarbyl of C1-a, and R3, R * and R5 are independently selected from a hydrocarbyl of C1-β-alkoxy or monoalkylene oxide or polyoxy-alkylene. Such ethers include, for example, tetrahydrofuran, methyl t-butyl ether, ethyl t-butyl ether, ethoxy ether, phenyl isobutyl ether, diethyl ether, diphenyl ether and diisopropyl ether. Mixtures of solvents such as t-butyl alcohol / hexane, tetrahydrofuran / toluene and tetrahydrofuran / heptane can also be used to obtain the desired properties of the solvent. The present preferred solvent, due to the high yields of HPA which can be obtained under mild reaction conditions, is methyl t-butyl ether. The hydroformylation reaction is carried out in the presence of a metal carbonyl hydroformylation catalyst, insofar as less than 50 mole% of the same, preferably less than 10 mole thereof is modified by phosphine. These catalysts are transition metals, particularly those metals of group VIII of the periodic table, for example cobalt, iron, nickel, osmium and the complexes described, for example, in US-A-3 161 672. However, they are obtained better results when a cobalt-based catalyst is used, with unmodified cobalt carbonyl compounds being preferred. The cobalt-based catalyst can be supplied to the hydroformylation reactor as a carbonyl cobalt such as dicobaltoctacarbonyl or cobalt hydridocarbonyl. It can also be supplied in essentially any other form which includes metal, supported metal, Raney cobalt, hydroxide, oxide, carbonate, sulfate, acetylacetone, salt or a fatty acid, or an aqueous cobalt salt solution. If it is not supplied as cobalt carbonyl, the operating conditions can be adjusted so that the cobalt carbonyls are formed, for example, via the reaction with H2 and CO as described in J. Falbe, "carbon monoxide in synthesis organic ", (" Carbon Monoxide in Organic Synthesis "), Springer-Verlag, NY (1970). Typically, these conditions will include a temperature of at least 50 ° C and a partial pressure of carbon monoxide of at least 0.8 MPa (100 psig). For a faster reaction, temperatures of 120 to 200 ° C can be used, at CO pressures of at least 3.5 MPa (500 psig). The addition of activated carbons of high surface area or of zeolites, especially those containing or supporting platinum or palladium metal, is known to accelerate the formation of cobalt carbonyls. Preferably, the catalyst is maintained under a carbon monoxide stabilizing atmosphere, which also provides protection against exposure to oxygen. The most economical and preferred method of catalyst activation and reactivation (catalyst reuse) involves converting the cobalt salt (or derivative) under H2 / C0 in the presence of the catalyst promoter used for hydroformylation. The conversion of CO2 to the desired cobalt carbonyl is carried out at a temperature in the range of 75 to 200 ° C, preferably 100 to 140 ° C and a pressure in the range of 7.0 to 34.6 MPa (1000 to 500). psig) for a time preferably less than about 3 hours. The operation step can be carried out in a pressurized re-blending reactor or in situ in the hydroformylation reactor. The amount of group VIII metal present in the reaction mixture will vary based on the other reaction conditions, but generally lies within the range of from 0.01% by weight to 1% by weight, preferably from 0.05 to 0.3% by weight. weight based on the weight of the reaction mixture. The hydroformylation reaction mixture preferably includes a catalyst promoter to accelerate the reaction rate. The promoter is generally present in an amount within the range of 0.01 to 0.6 moles per mole of group VIII metal. Suitable promoters include mono- and multivalent metal cation sources of weak bases such as alkali metal, alkaline earth metal salts and-1 C-rare earth metals of carboxylic acids. Suitable metal salts include sodium, potassium and esio acetate, propionates and octoates; calcium carbonate and lanthanum acetate. The currently preferred metal salt is sodium acetate. Also available are lipophilic promoters such as lipophilic monohydroxyanenes or dihydroxyacenes, lipophilic tertiary amines or arsines, or arsine oxides respectively of lipophilic phosphine oxides, which accelerate the rate of hydroformylation without imparting hydrophilicity (solubility in water) to the active catalyst. As s = used in the present (lipophilic) means that the promoter tends to remain in the organic phase after extraction of HPA with water. Suitable monohydroxyane or dihydroxyane lipophilic lixes include those represented by formulas (3) and (4): C6R50H (3) C6R5 (0H) 2 (4) wherein each R group is independently selected from hydrogen, a halide, a cyclic or aromatic, linear or branched Cx_25 hydrocarbyl, alkoxy or monoalkylene oxide or polyalkylene oxide, or in which two or more R groups together form a structure of ring. Examples include phenol, nonylphenol, methylphenol, (...), isopropylphenol, 2,2-bis (4-hydroxyphenyl) propane, naphthol, hydroquinone, catechol, dihydroxynaphthalenes and dihydroxyanthracenes. Excellent results have been obtained with phenol and nonylphenol, which are, therefore, preferred. Suitable lipophilic amines and arsines include those represented by formulas (5) and (6): NR'3 (5) AsR'3 (6) wherein each R 'group is independently selected from a linear, branched, cyclic and aromatic C1-25 hydrocarbyl, alkoxy or monoalkylene oxide or polyalkylene oxide, or in which two or more of the R1 groups, together, form a ring structure. Such arsines include triphenylarsine and triethylarsine. Examples in which two or more of the R 'groups together form a ring structure include pyridine and substituted pyridines described by the formula (7): (7) -in which each of the groups A is independently selected from hydrogen or a linear, branched, cyclic or aromatic C1-25 hydrocarbyl, two or more of which may form a ring structure. Substituted pyridines in which A1 and A5 are both bulky groups, such as t-butyl, are not preferred. The lipophilic tertiary amine is preferably a non-chelating amine or an acid conjugate having a pKa in the range of 5 to: 1. Such lipophilic tertiary amines include dimethyldodecylamine, pyridine, 4- (1-butylpentyl) pyridine, quinoline, isoquinoline, lipidine and quinaldine. The preferred amine is nonylpyridine. Suitable phosphine oxides and arsine oxides include those represented by formulas (8) and (9): O = PR "3 (8) O = AsRn3 (9) wherein each R "group is independently selected from a halide, a linear, branched, cyclic or aromatic C1-25 hydrocarbyl, alkoxy or monoalkylene oxide or polyalkylene oxide, or in which two or more R groups, together, form A ring structure Such phosphine oxides include / in triphenylphosphine oxide, tributylphosphine oxide, dimethylphenylphosphine oxide and triethylphosphine oxide The currently preferred phosphine oxide is triphenyl phosphine oxide.It is usually preferred to regulate the concentration of water in the hydroformylation reaction mixture since excessive amounts of water reduce the selectivity towards the 1,3-alan diols and 3-hydroxyaldehydes below nivsles or acceptable concentrations can induce the formation of a second liquid phase. The water can help promote the ormation of the desired cobalt carbonyl catalyst species.The acceptable water concentrations depend The solvent solvent used, with more polar solvents, is generally more tolerant of higher water concentrations. For example, optimal water concentrations for hydroformylation in the methyl-t-butyl ether solvent are considered to be within the range of 1 to 2.5% by weight. Hydrogen and carbon monoxide are generally introduced into the reaction vessel in a molar ratio in the range of 1: 2 to 8: 1, preferably 1: 1.5 to 5: 1. The reaction is carried out under effective conditions to produce a hydroformylation reaction mixture comprising a major portion of 3-hydroxy: aldehyde and a minor portion of a by-product, if any. In addition, the concentration of 3-hydroxy aldehyde in the reaction mixture is preferably maintained at less than 15% by weight, preferably 5 to 10% by weight. (To provide solvents having different densities, the concentration of 3-hydroxy aldehyde in the reaction mixture can be expressed in motility, ie, less than 1.5M, preferably within the range of 0.5 to 1M.) • Suitably, the reaction is carried out at an oxirane concentration which is less than 12% by weight. Generally, the hydroformylation reaction is carried out at an elevated temperature of less than 100 ° C, preferably from 60 to 90 ° C, more preferably from 75 to 85 ° C and at a pressure in the range of 3.5 to 34.6 MPa. (500 to 5000 psig), preferably (for economic processes) 7.0 to 24.2 MPa (1000 to 35,000 psig), with higher pressures generally imparted to higher selectivity. The concentration of 3-hydroxyaldehyde in the intermediate product mixture can be controlled by regulation of the process conditions such as the oxirane concentration, the catalyst concentration, the reaction temperature and the residence time. In general, relatively low reaction temperatures (less than 100 ° C) and relatively short residence times within the range of 20 minutes to 1 hour are preferred. In the practice of the method of the invention, it is possible to obtain yields of 3-hydroxyaldehyde (based on the conversion of oxirane) of more than 80%. For example, with the hydroformylation of EO in the presence of a cobalt carboryl formation of not more than 7% by weight of HPA in a diluted hydroforming product mixture, at speeds greater than 30 h "1 are available. Catalysts are also mentioned here in terms of "replacement frequency" or "TOF" and are expressed in units of moles per mole of cobalt per hour, oh '1.) The reported speeds are based on the observation that, before Since most of the oxLrano is converted, here EO, the reaction is essentially of zero order, in the EO concentration and proportional to the cobalt concentration, as mentioned above, the hydroformylation product mixture is brought to It is preferable that the aqueous liquid is water.The quantity of water added to the mixture of the hydroformylation reaction product will generally be such that the amount of water added to the mixture of the hydroformylation reaction product will generally be such that it provides a weight ratio of water: mixture within the range of 1: 1 to 1:20, preferably 1: 5 to 1:15.

The addition of water at this stage of the reaction may have the additional advantage of suppressing the information of ceased ends ::? undesirable. Extraction with a relatively small amount of water provides an aqueous phase which is greater than 20% by weight of 3-hydroxyaldehyde, preferably greater than 35% by weight of 3-hydroxyaldehyde, which allows the economical hydrogenation of 3 - hydroxyaldehyde to 1,3-alkanediol. The water extraction is preferably carried out at a temperature within the range of 25 to 55 ° C, avoiding higher temperatures to minimize the condensation products (heavy ends) and the disproportionation of the catalyst to inactive compounds, metals; of group VIII soluble in water (for example, cobalt). In order to maximize the recovery of catalyst described above, it is preferred to carry out the extraction of water under 0.5 to 1.5 MPa (50 to 200 psig) of carbon monoxide at a temperature of 25 to 55 ° C. The process of the invention can be conveniently described with reference to Figure 1. By way of example, the hydroformylation of EO as oxirane will be described. Separate or combined currents of EO (1), carbon monoxide and hydrogen (2) are charged to the hydroformylation vessel (3), which can be a pressure reaction vessel such as a bubble column or a stirred tank, which They operate in batch mode or continuously. The feed systems are connected in the presence of an unmodified cobalt-based catalyst, that is, a cobalt carbonyl compound which has not been reacted with a phosphine ligand. After the hydroformylation reaction, the mixture (4) of the formy reaction product containing HPA, the PDO reaction solvent, the cobalt catalyst and a minor amount of reaction by-products, are passed to the vessel (5) of extraction, to which an aqueous liquid is added, generally water and optionally a miscible solvent, by means of (6) the extraction and concentration of the HPA for the subsequent hydrogenation step. Liquid extraction can be affected by any suitable means, such as packaged mixer-settlers or driven extraction columns or by rotary disk contracting machines. If desired, the extraction can be carried out in multiple stages. The mixture of the hydroformylation reaction product containing water can be passed to a settling tank (not shown) for aqueous and organic phase resolution. The organic phase containing the reaction solvent and the main portion of the cobalt catalyst can be reused from the extraction vessel to the hydroformylation reaction via (7). The aqueous extract (8) is optionally passed through one or more beds (9) of acid ion exchange resin for the removal of any cobalt catalyst present, and the mixture (10) of aqueous product subjected to cobalt removal is passed through. a hydrogenation vessel (11) and reacting with hydrogen (12) in the presence of a hydrogenation catalyst to produce a mixture (13) of hydrogenation product containing PDO. The hydrogenation step can also be reversed from the last ends to the PDO. The solvent and the extractant water (15) can be recovered by distillation in the column (14) and recycled to the water extraction process by means of additional distillation (not shown) for the separation and purging of clear ends. The stream (16) containing PDO can be passed to one or more distillation columns (17) for the recovery of PDO (18) from the heavy ends (19). The process of the invention allows the selective and economic synthesis of PDO at moderate temperatures and pressures without the use of a phosphine ligand for the hydroformylation catalyst. The process involves the preparation of a reaction product mixture diluted in HPA, then the concentration of this HPA by extraction of water and subsequent hydrogenation of HPA to PDO.

Comparative Example 1 The experiment illustrates the hydroformylation of ethylene oxide (EO) catalyzed by a phosphine modified cobalt catalyst derived from dicobal toctacarbonyl. A test reactor of 300 ml is charged with 0.87 g of dicobaltoctacarbonyl, 1.33 g of bis (1,2-diphenylphosphino) -ethane, 0.125 g of sodium acetate trihydrate, 0.51 g of 2-ethylhexane acid and 147.2 g. g of "NEODOL" 23 (trademark), a mixture of C12 and C13 alcohols. The content of the reactor is heated to 165 ° C under a synthesis of H2: CO 1: 1 gas for 1 hour, with stirring at 1000 rpm, to prepare the active catalyst. The reactor temperature decreases to 90 ° C and 20 g of EO are injected (ie 11.8% by weight) by means of a "blow-covered" container charged with 10.4 MPa (1500 psig) of synthesis gas. The reactor pressure is maximized up to 10.4 MPa (1500 psig). The reactor pressure decreases with time as a result of the hydroformylation of the EO substrate. The reactor is re-filled with 10.4 MPa (1500 psig) with 1: 1 H2. CO before the decrease in pressure of 9.1 MPa (1300 psig). In this way, the uptake of gas synthesis can be verified by the function of time, to follow the course of the reaction. Samples of the reaction mixture are periodically extracted in cooled n-propanol containing an internal standard (toluene or ethyl acetate) for analysis by capillary gas chromatography (with flame ionization detector). The analysis indicates an 87% conversion of EO in 3 hours to provide 10 weight percent of the 3-hydroxypropanal intermediate (HPA), with some less hydrogenation to 1,3-propanediol (PDO). This result corresponds to an effective reaction rate of 15 moles of HPA formed per mole of CO catalyst per hour (TOF). The apparent selectivity to acetaldehyde, expressed as the molar ratio of acetaldehyde to the sum of HPA and acetaldehyde, is 27%. £ i_l A batch reactor with stirring of 300 ml under nitrogen is charged with 0.87 g of dicobaltoctacarbonyl, 1.5 g of toluene (internal indicator), 1.5 g of undecanol (second indicator) and 147 g of methyl t-butyl ether (MTBE). . The nitrogen atmosphere is purged with H2 before the reactor is filled with 8.3 MPa (1200 psig) with 1: 1 CO / H2. The reactor slurry is heated at 80 ° C for 5 minutes, before the injection of 20 g of EO, with simultaneous increase in reactor pressure to 10.3 MPa (1500 psig) at a H2 / CO ratio of 2.3. The concentration of EO at the start of the reaction is 11.7% by weight. The content of the reactor is sampled and analyzed. The formation of 2.7% by weight of HPA is observed after 30 minutes, for a speed of 20.2 h "1.

The conditions of Example 1 are repeated with the addition of 0.5 g of dimethyldodecylamine and the injection of 12 g of EO (ie 7.4% by weight). Sampling after 45 minutes of reaction indicated the formation of 5.7% by weight of HPA, for a speed of 31 h "1. This corresponds to an increase in the speed of 1.5 times compared to that observed in the absence of the promoter. It is continued until the formation of 10% by weight of HPA until a complete virtual conversion of ethylene oxide.After the reaction, the mixture is cooled to 25 ° C and extracted with 30 g of deionized water under 2.1 MPa (300 psiig) of CO. The mixture is then transferred to a separation vessel under 0.7 MPa (100 psig) of CO. The separation provides 30.75 g of a lower aqueous layer containing 24.0% by weight of HPA and a top layer of organic solvent. containing 1.0% by weight of HPA The colorimetric analysis of the upper and lower layers indicates that 94% of the cobalt catalyst is in the upper solvent layer, demonstrating the separation of most of the cobalt catalyst, of the greatest part of the HPA product.

Comparative Example 2 This experiment illustrates the separation of HPA from the cobalt hydroformylation catalyst by illation. 113.45 g of the EO hydroformylation reaction product containing 14.32 g of the HPA intermediate are diluted with 50.1 g of tetraethylene glycol dimethyl ether. The mixture is illed by means of a short path batch fixed at 10 mmHg under a slow nitrogen purge at a illate residue temperature ranging from 66 CL 108 ° C. The illate extractions are collected and are found by cro atographic analysis of gases containing 6.32 g of HPA. There is no evidence of HPA in the remaining waste sample, which show a significant increase in the heavier components than HPA. Therefore, the total HPA recovery is 44% and the rest is degraded to heavy extremes.

This experiment demonstrates the inherent problems in the thermal separation of the highly reactive HPA intermediate from the reaction mixture. More than half of the HPA agent is degraded during separation.

This experiment of the invention demonstrates the separation and concentration of HPA by extraction with water. 1507.6 g of EO hydroformylation reaction product (MTBE solvent with sodium acetate promoter at 0.2 Na / CO) containing 6.0% by weight of HPA intermediate is extracted at 25 ° C under 0.8 MPa (100 psig) of nitrogen in a stirred reactor, with 298 g of deionized water, which provides 400.5 g of a lower layer containing 20.8% by weight of HPA intermediate (concentration 3.5 times). The equilibrium of total HPA material from gas chromatographic analysis of the fed, the upper and the lower phases indicate a complete recovery of HPA within the experimental error by g.c. The top layer after extraction with water contains 0.14% by weight of cobalt, or 65% of the initially charged catalyst.

This experiment demonstrates the advantages of recovery of catalyst and product of the invention by the PDO preparation method. The separation of HPA from the reaction mixture is very efficient and selective. The use of water and low temperatures prevents the degradation of HPA which is shown in comparative example 2. The method also allows the concentration of HP? for more efficient hydrogenation and final recovery. In addition, a significant fraction (65%) of the cobalt catalyst is already separated from the aqueous HPA product, making possible an efficient reuse of the catalyst with the reaction solvent. .o_.

An agitated batch reactor of 300 ml is charged under nitrogen with 0.87 g of dicobaltoctacarbonyl, 1.5 g of toluene (internal indicator), 2 g of deionized water and 146 g of MTBE. The nitrogen atmosphere is purged with H2, and the reactor is filled to 4.2 MPa (600 psig) of H2 and then to 8.4 MPa (1200 psig) with 1: 1 of CO / H2. The contents of the reactor are heated to 80 ° C for 1 hour and then 10 g of EO (6.2% by weight) are injected, with simultaneous increase in reactor pressure to 10.4 MPa (1500 psig) by the addition of 1 : 1 CO / H2. The content of the reactor is shown and analyzed at approximately 40% and almost 100% conversion of EO, which occurs in the following two hours. At a conversion of approximately 40%, 3.3% by weight of HPA have been formed at a rate of 18 h_1. _to_ Example 4 is repeated in the absence of added water and with the addition of 0.14 g of sodium acetate trihydrate as a promoter, added in a Na / Co ratio of 0.2. The concentration of EO at the start of the reaction is 6.3% by weight. HPA is formed at a rate of 41 h "1. After cooling and the addition of 30 g of deionized water for extraction, 77% of the cobalt catalyst remains with the upper solvent layer, 23% of the cobalt is extracted with the aqueous product This fraction corresponds approximately to the amount of sodium acetate added to promote the reaction.

Examples 6 to 11 These experiments illustrate the effectiveness of lipophilic promoters such as phenol, nonylphenol, hydroquinone, 4- (1-butylpentyl) pyridine, triphenylarsine, and triphenylphosphine oxide both to accelerate the hydroformylation reaction and to allow the reuse of essentially all of the catalyst. cobalt in the organic phase after extraction with water of the HPA product. Example 4 is repeated with the addition of, respectively, 0.12 g of phenol (example 6), 0.25 g of nonylphenol (7), 0.14 g of hydroquinone (8), 0.27 g of 4- (l-butylpentyl) pyridine (9 ), 0.4 g of triphenylarsine (10) or 0.4 g of triphenylphosphine (11) as a promoter, for a ratio of 0.25 moles of promoter per mole of cobalt (11 to 0.26) and an EO concentration at the start of the reaction, the range of 6.2 to 6.3% by weight. The content of the reactor is sampled and analyzed at approximately 50% conversion and up to full virtual conversion. After the reaction, the mixture is cooled to room temperature. Approximately 30 g of deionized water are added for extraction of the product under 1.5 MPa (200 psig) of synthesis gas. After 30 minutes, mixing is completed and the aqueous product layer containing HPA is isolated. Both layers are analyzed. The results of these experiments are summarized in the "abla." From the table it can be understood that the use of a promoter provides an increase in velocity with respect to that observed in the absence of the promoter in Example 4. The reuse of the cobalt with the organic layer represents a substantial reduction in cobalt loss in relation to that observed with the promotion by sodium acetate in Example 5. 2-12.

This example illustrates the hydrogenation of aqueous HPA obtained from extraction with water of the EO hydroformylation product. 333.4 g of the extract containing 20% by weight of HPA are added to a 500 ml autoclave reactor containing 5.07 g of a powdered nickel hydrogenation catalyst (Calsicat E 475SR, 50% Ni). The reactor is charged with 7.0 MPa (1000 psig) of H2 and heated at 60 ° C for 3 hours. At this time, the gas chromatographic analysis indicates 99% ie conversion of HPA, 93% selectivity of PDO (moles of PDO formed divided by the moles of PHA consumed) and 3% selectivity for propanol. The reaction temperature is increased to 90 ° C for one hour, after which a conversion of HPA in excess of 99%, to an apparent selectivity of 99% of PDO and 3.5% of propanol is indicated. The heating is continued for an additional hour at 110 ° C to further improve the selectivity towards PDO by reversing the heavy ends formed during hydroformylation or early hydrogenation. ¿? 13 In order to examine the role of the promoter, a series of reactions are carried out in a small-scale reactor fitted with optical systems for infrared analysis in situ. In the first reaction, 80 mg (0.234 millimoles) of recrystallized dicobaltoctacarbonyl (from CH2C12) are added to 17 ml of dry MTBE and distilled at the bottom of the 30 ml reactor fitted with an infrared crystal ZnS (45). The upper part is closed in the unit and the reactor assembly is removed from the dry box. The inert atmosphere is replaced with carbon monoxide by alternately pressing the reactor to 1.5 MPa (200 psig) with CO / then depressurizing the vessel to atmospheric pressure for a total of 3 cycles. The unit is finally pressurized for 1.5 MPa (200 psig) with CO. The unit is then heated to 80 ° C and the pressure in the reactor is adjusted to 2.7 MPa (375 psig) with pure CO. 1.2 g (27 mmol) of EO (ie 8.5% by weight) are added to the reactor at hydrogen gas pressure, which gives the total pressure inside the unit at 11.1 MPa (1600 psig) to produce a 3: 1 gas cover; H2: CO. The infrared spectra are recorded at 3 minute intervals to verify the progress of the reaction. The president in the unit it decreases due to gas consumption and synthesis gas is added (1: 1) as required to maintain the total pressure in the reactor between approximately 10.8 and 10.4 MPa (1550 and 1500 psig). A profile of the pressure and temperature data of the reactor is measured digitally by means of a transducer and a thermocouple. The second reaction is carried out in a similar manner except that 16 mg is also added (0.096 millimoles) of sodium octoate to the reaction mixture. Again, the concentration of EO at the start of the reaction is 8.5% by weight. The rate of formation of HPA is calculated from the consumption of synthesis gas and verified against the appearance of aldehyde at 1724 cm "1 and the disappearance of the EO band in the infrared spectrum at 870 cm" 1. The TOF of the reaction in the absence of a promoter is 15 h "1, and in the presence of sodium octoate, the TOF is 41 h" 1. At the beginning of the reaction, the infrared spectrum of the catalyst region (2300-2000 cm "1) shows characteristic patterns of dicobaltoctacarbonyl.The reaction proceeds in the absence of a promoter that does not show change in this infrared reaction over the course of In contrast, the reaction carried out with the promoter changes rapidly producing a characteristic pattern of the cobalt acyl complex in addition to the dicobaltoctacarbonyl standards This indicates that the promoter changes the stage that determines the speed in the reaction cycle , which results in a faster total reaction rate It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (16)

1. A process for preparing 1,3-alkanediols and 3-hydroxyaldehydes by hydroformylating an oxirane with carbon monoxide and hydrogen in the presence of one or more hydroformylation catalysts based on group VIII metal which may contain up to 50 mole% based on the metal of the catalysts modified by phosphine, and in the presence of an organic solvent, in which the concentration of the oxirane at the start of the reaction is less than 15 weight percent (% by weight), based on the weight of the Total liquid reaction mixture.

2. The process according to claim 1, characterized in that the concentration of the oxiranc is less than 12% by weight.

3. The process according to claim 1 or 2, characterized in that the oxirane is a hydrocarbyl-epoxide having from 2 to 30 carbon atoms.

4. The process according to claim 1 or 2, characterized in that the oxirane is ethylene oxide.

5. The process according to any of the preceding claims, characterized in that the solven :: e is inert and essentially immiscible in water.

5 m The process according to any of the preceding claims, characterized in that the amount of hydroformylation catalyst is in the range from?!? L to 1.0% by weight based on the weight of the reaction mixture.

7 # The process according to any of the preceding claims, characterized in that the metal of group VIII is cobalt.

8. The process according to any of the preceding claims, characterized in that up to 10 mol% of one or more hydroformylation catalysts

based on a metal of group VIII are modified by phosphine.

9. The process according to any of the preceding claims, characterized in that one or more hydroformylation catalysts based on metal of group VIII are cobalt carbonyl compounds not modified by a phosphine.

10. The process according to any of the preceding claims, characterized in that the reaction fish comprises a lipophilic promoter.

11. The process according to claim 10, characterized in that the promoter is present in an amount in the range from 0.01 to 0.6 mles per mole of group VIII metal.

12. The process according to claims 10 or 11 characterized in that the lipophilic promoter is selected from sources of monovalent and multivalent metal cations of weak bases; monoh: .Dioxarenes or lipophilic dihydroxyacenes represented by the formulas (3) and (4):

C6R5OH (3) C6R5 (OH) 2 (4)

wherein each R group is independently selected from hydrogen, a halide, a linear, branched, cyclic or aromatic C1-2S hydrocarbyl, alkoxy or monoalkylene oxide or polyalkylene oxide, or in which two or more R groups together form a ring structure; amines or lipophilic tertiary arsines represented by formulas (5) and (6):

NR '3 (5) AsR' 3 (6) - - in which each R 'group is independently selected from a linear, branched, cyclic and aromatic C: .J5 hydrocarbyl, alkoxy or monoalkylene oxide or polyalkylene oxide, or wherein two or more of the groups R1, together, form a ring structure, and lipophilic phosphine oxides respectively arsine oxides represented by the formulas (8) and (9):

O = PR "3 (8) 0 = AsR" -, (9)

in the rows each group R "is independently selected from an aluro, a linear, branched, cyclic or aromatic C.sub.2 S hydrocarbyl, alkoxy or monoalkylene oxide or polyalkylene, or in which two or more R groups, together, form a ring structure.

13. The process according to claims 10 or 11 characterized in that the lipophilic promoter is selected from sodium acetate, phenol and nonylphenol, pyridine, 4- (1-butylpentyl) -pyridine, nonylpyridine, triphenylarsine and triphenylphosphine oxide.

14. The process according to any of the preceding claims, characterized in that the oxirane is hydroformylated with hydrogen and carbon monoxide in a molar ratio within the range of 1: 2 to 8: 1.

15. The process according to any of the preceding claims, characterized in that the level of 3-hydroxyaldehyde in the reaction mixture is maintained at less than 15% by weight.

16. The process according to any of the preceding claims, characterized in that the 3-hydroxyaldehyde is hydrogenated to provide 1,3-alkanediol.