DE1256206B - Process for the production of largely aldehyde-free alcohols by the oxo process - Google Patents

Description

Process for the preparation of largely aldehyde-free alcohols according to the oxo process The present invention relates to an oxo process in which the product consists predominantly of alcohol.

In the oxo process, as is usually done, olefins are used with carbon monoxide and hydrogen in the presence of a catalyst at elevated temperatures and pressures reacted to produce aldehydes as primary products. The aldehydes can then be hydrogenated to alcohols after a cleaning treatment.

In the technical implementation of the Oxo process considerable Losses in the purification of the intermediate aldehyde products and also in the hydrogenation stage on. Accordingly, it would be desirable to modify the known oxo processes in such a way that that a high proportion of alcohol is obtained directly. However, if the crude aldehyde mixture is hydrogenated without separating the conventional cobalt carbonyl catalyst, so will the cobalt carbonyl catalyst is decomposed by hydrogen, and there is a considerable amount going on Amount of this expensive catalyst component is lost. It was also found that conventional direct hydrogenation (e.g. with Raney nickel catalyst) of the crude aldehyde mixture resulting from the carbonylation step for formation of undesirable impurities, such as alcohols and acetals, which leads to what the yield reduced and the subsequent cleaning more difficult.

It has been found that the oxo process with reaction of olefins with 3 to 13 carbon atoms with carbon monoxide and hydrogen in Presence of catalysts, the reaction initially taking place at low temperature, is then carried out at a higher temperature, largely aldehyde-free alcohols can produce.

The method is characterized in that the temperature is at an initial temperature of 50 to 1800C, over 180 to 200 "C in the middle range a final temperature of 205 to 225 or 220 "C is increased during the reaction.

This is surprising, since German patent specification 888 094 is known, the temperature of the oxo process in the range of 80 to 1500C during the reaction to increase continuously, but a higher proportion of aldehydes and ketones is obtained.

The process of the present invention is based on the continuous one Reaction of a mixture of olefin, carbon monoxide and hydrogen in a tubular Reaction vessel with exothermic reaction, which is controlled so that a continuous predetermined positive temperature gradient present in the entire length of the pipe is. It is also part of the present invention, the hydrogen carbon monoxide - To keep the ratio within the starting and ending areas so that alcohol formation among the numerous competing reactions of the Oxo process will.

As a result of detailed kinetic studies it was found that the total oxo process, which consists primarily of the hydroformylation stage from olefins to aldehydes, then in the hydrogenation of aldehydes to alcohols, is composed of a large number of simultaneous reactions in each stage. At the same time, the olefins present in the hydroformylation stage are in one hydrogenated to some extent to paraffin compounds. However, this is an undesirable one Result, and it is an advantage of the present invention that such losses to be largely reduced in olefins.

The method of the present invention makes a product possible in which the aldehyde content is 0.1% by weight or less.

The inventive method is carried out in a continuous reaction system, preferably carried out in a tubular reaction vessel.

In this device the stream of reactants moves progressively through the reaction vessel, with essentially no longitudinal mixing. In a another embodiment of the The method according to the invention is described in worked a number of autoclaves, the temperature in each autoclave such is controlled that the reaction mixture continuously from an autoclave to the finds next optimal temperature conditions. It has been found that a variety Row-wise autoclave in the effectiveness of a continuous tubular Reaction vessel is equivalent. Combinations of sections of tubular reaction vessels together with a stirred autoclave are particularly feasible if highly reactive Olefins are brought into contact.

In the preferred embodiment of the invention it is not necessary Add or remove material from the reaction vessel until the products are at the end removed from the reaction vessel. However, in some cases it can be desirable be able to make use of a reaction vessel system with a multiple inlet, in which additional proportions of carbon monoxide and / or hydrogen (as desired) can be added during the course of the reaction.

The continuous reaction vessel system is with temperature control means equipped to keep the temperature at a desired level in all points of the entire system is maintained.

It is primarily the exothermic heat of reaction in such a Way controlled that a temperature profile, corresponding to the passage of the reaction mixture by the reaction vessel system. The drawings explain the critical Limiting the temperature of the reaction mixture as used by thermocouples were attached in the reaction mixture, was measured.

Drawing 1 explains the maximum and minimum range in which the temperature of the reaction mixture, based on its respective position in the reaction vessel, must be maintained. In general, the temperature profile has an initial temperature of 50 to 178 "C, a mid-range temperature of 180 to 2000 C, and a final temperature of 205 to 2200 C. Within these broad temperature ranges, temperature ranges specific to particular olefin feedstocks are preferred, as follows is shown. Olefin initial 1 middle t final Range (° C) Propylene for the production of n- and i-butanols. . 100 to 140 1 180 to 200 205 to 220 Hepten for the production of octyl alcohols. . . 100 to 150 180 to 200 1 205 to 220 Witches for making mixed heptyl alcohols. . . 100 to 150 1 180 to 200 205 to 220 Propylene trimer for the production of Clw, alcohol ... 100 to 178 1 180 to 200 1 205 to 220 Propylene tetramer for production mixed C13 alcohol hole .. ........ ........ ... 100 to 160 180 to 200 205 to 22D In contrast to the temperature conditions illustrated in Drawing 1, the remaining drawings show certain other temperature conditions which have been found to be undesirable for the operation of a uniform Oxc process.

Drawing 2 shows the rapid temperature rise that occurs during reactions occurs that lack adequate temperature control; drawing 3 explains the approximately isothermal work at low temperatures and drawing 4 working at medium temperature; Drawing 5 is typical of the isothermal Working at a high temperature; Drawing 6 explains the use of a Temperature gradient at relatively high temperatures.

To the present continuous reaction and the production of high Carrying out alcohol proportions in addition to small amounts of aldehyde is preferred certain reaction conditions within specific limits. You can at In accordance with the invention, the competing reactions, which in the primary oxoation and subsequent hydrogenation in line with that here the temperature control system described. Preferably should also other variable quantities, such as the hydrogen-carbon monoxide ratio, be kept within certain limits. It has been found that the use of the temperature gradient system is advantageous if a specific CO: H ratio is used, i.e. H. the inlet gas feed to the reactor should less than 6001, contain hydrogen in the hydrogen-carbon monoxide mixture, whereby a preferred range is 0 to 50 volume percent. In addition, the The proportion of hydrogen that escapes with the carbon monoxide in the discharge gas is less than 20 percent by volume of the initial mixture of carbon monoxide and hydrogen gases be, with a preferred proportion range at 50 to 3 ° / 9 hydrogen, based on the total volume of hydrogen and carbon monoxide.

In one embodiment of the method, the amount of hydrogen follows over the length of the tubular reaction vessel a negative or decreasing Course ratio. It was found that it sounds as a percentage of hydrogen The amount of hydrogen expressed in the gas phase in inverse proportion to the temperature-length ratio stands.

Furthermore, it was found that the numerical product of the designated absolute value of hydrogen percentage and temperature (0 C) in any one Point of reaction length is 1500 to 10,000. For example, at Working with graft trimer the starting hydrogen percentage is about 40 D / oo At the same point, the temperature is around S ° C and the multiplication product of hydrogen percentage and temperature is 2000. At the center of the reaction vessel the hydrogen percentage is about 30 while the temperature is about 200 "C. The product at this point is therefore 6000. Ultimately, it is at the exit of the reaction vessel, the hydrogen percentage is about 10 and the temperature about 225 ° C.

Accordingly, the product of temperature and hydrogen content is 2250. If propylene is used, the corresponding calculations are: H2 temperature J product Output .. 60% x 1200C = 7200 Middle. . . 50O / ox 1800C = 90009000 End . . 10 ° lo x 1900C = 1900 The catalyst used in the practice of the present invention can be any of the conventional cobalt catalysts such as a cobalt carbonyl, a cobalt carboxylate, e.g. B. cobalt isodecanoate, a cobalt oxide, cobalt carbonate, cobalt hydroxide or cobalt metal. These sources of cobalt are added to the reaction system in the usual manner, thereby being converted into a cobalt carbonyl which is generally believed to be the effective carbonylation catalyst. It is an advantage of the present process that the cobalt carbony already present as a carbonylation catalyst is also fully effective as a hydrogenation catalyst.

It has also been found that cobalt in the process according to the invention from the reaction vessel is not removed, what in the presence of excess Hydrogen would be expected. It is not desirable to have cobalt in the latter part of the To precipitate reaction zone because such cobalt form a sludge or as heavy Deposition would plate the reactor *, something difficult from the walls of the reaction vessel would have to be removed. In general, cobalt should be present in the reaction mixture in an amount from 0.3 to 1.0 percent by weight, calculated as cobalt metal based on weight of the total loading table.

The pressure used in the present oxoation is critical variable size and can be kept in the range of 141 to 703 kglcm2.

The introduction of water into the reaction vessel is another variable Size which has been found to control the process. That Water can go along with the olefins, hydrogen, carbon monoxide and the catalyst may be added at the beginning of the reaction vessel system, or it may preferably in the later stages of the reaction in a reaction vessel system with multiple Inlet system are introduced. It has been found that the introduction of water the formation of severe orguiischea residues is reduced. The amount of water used is less than 10 percent by weight, based on the weight of the total reaction mass, a preferred range being 0.2 to 5 percent by weight water. It was found, for example, that the introduction of about 4 percent by weight of water, preferably in the last half of the tubular reaction vessel, it allows increase the production of alcohol by approximately 5 equivalent mole percent.

The residence time of the tube passing through the reaction vessel Reaction mixture can change from 0.4 to 3 hours.

Example 1 The oxoation of propylene trimer was carried out in a continuous tubular reaction vessel of 7.62 m in length carried out. The reaction vessel became Divided into four zones, each about 1.8 m long, to provide independent temperature control areas for maintaining the desired temperature profile during the process to create the exothermic reaction. Propylene trimer was used in a ratio of 5.22 kg per hour (0.413 kg / mole3 charged, while the feed gas mixture of Hydrogen and carbon monoxide (H2: CO ratio 45:55) in the ratio of 0.159 kg / mole hour was charged. The catalyst was in the system as a slurry of cobalt 2-hydroxide with propylene trimer in an amount of about 0.102 kg of the cobalt compound introduced per hour.

It was observed during the course of the oxoation process that the designated cobalt hydroxide was rapidly converted to cobalt carbonyl, which is the effective catalytic component (although very good results were also obtained at 160 ° C as the first rise temperature). The temperature along the reaction vessel, in relation to the residence time of the trimer charge, is shown in drawing 2, based on the total residence time of 0.6 hours. The specific temperatures corresponding to the points along the reaction vessel were: Temperature dwell time (hours) ° C or% of long 50 0 0 (or incoming delivery temperature) 150 0.05 1 8.3 189 0.1 1 16.7 195 0.2 33.3 210 0.3 50 216 0.4 66.7 218 0.5 83.3 222 0.6 100 Under the above operating conditions, 76.90 liters of isodecyl alcohol, based on the propylene trimer charged, and less than 0.1 ° lo isodecyl aldehyde were obtained. About 1001o of the exit gas was hydrogen.

The analytical results of this example and of examples 2 to 6 are summarized in the table below.

Analysis of the products At- i-decyl- i-decyl- reverse game run nonane nonene aldehyde alcohol stand 1 7 11.3: 0 0.1 76.9 11.7 2 4 28.5 3.0 0.5 59.0 9.1) 3 1 4.0 40.0 39.0 10.0 7.0 4 2 4.0 '13.0 30.0 18.0 35.0 5 3 25.0 2.0 6.0 57.0 10.0 6 5 28.5 3.0 0.5 62.5 l 9.0 Example 2 In order to distinguish the controlled temperature sequence procedure of Example 1 from an adiabatic type of reaction, the procedure was carried out using the equipment and general procedure of Example 1, but under adiabatic conditions. It was calculated that at an inlet temperature of 50 "C, the maximum temperature in the reaction mixture would reach approximately 400" C. The temperature profile resulting from this working process is recorded in drawing 2.

Example 3 The procedure of Example 1 was followed essentially below isothermal conditions by appropriately controlling the temperatures in the cooling jackets carried out by each of the four zones of the reaction system. The temperature was held constant at 135 to 140 "C in each of the zones. It was found that at Only about 1001 of the product isodecyl alcohol work under these conditions was, although the conversion to isodecylaldehyde was 390/1 or increased. Because of the low conversion, the amount of propylene trimer which emerged from the reaction increased, to 40 percent by weight of the original amount of olefin. That in this process The temperature profile obtained is shown in drawing 3.

Example 4 The procedure of Example 1 was followed with the modification carried out that an isothermal reaction in the medium temperature range by suitable control of the cooling jacket temperatures in the corresponding reaction vessels was carried out.

The temperature was thus maintained at 140 to 155 "C in each zone. It was found that under these conditions 18 ° lo of the original olefin were converted to isodecyl alcohol. The conversion to isodecylaldehyde was significant larger and corresponded to 300 / ü. However, there remained a residue of 350 /. This working method is not practicable because of the low yield. The temperature profile this process is recorded in drawing 4.

Example 5 The procedure of Example 1 was followed with the modification carried out that an isothermal reaction at a higher temperature by suitable Control of the cooling jacket temperatures carried out in the corresponding reaction zones became. The temperature was 214 to 231 "C in the total area with a mean temperature of 231 "C and the final temperature of 2240 C. In this process, according to the summarizing Table 25 0 / o nonane obtained by hydrogenation of the starting nonane, that is to say an essential one Part of the olefin feed by hydrogenation to a non-reactive paraffin lost. The temperature profile of this process is shown in drawing 5.

Example 6 The procedure of Example 1 was followed with the modification carried out that one by the heat of the exothermic reaction, the reactants let it come to a high temperature very quickly, which then gradually decreases became. So it was not the temperature over the entire length of the reaction vessel gradually increased - but the temperature was only in the first third of the Reaction vessel is allowed to rise gradually while in the remaining two Third of the length of the reaction vessel with a gradually falling temperature curve was worked. The temperature profile obtained during this process is shown in the drawing 6, with the initial temperature at the beginning of the reactor 214 "C, the midpoint temperature 231 "C and the final temperature was 2240 C. The analytical results obtained from the product Data show that this working method has excessive losses in output notes, since 28.5% of the product was converted to nonane.

Example 7 The oxoation of propylene was carried out in two reaction vessels carried out. In the first stage of the oxoation was a pot reactor with a Propeller agitator used, in which the temperature was kept at 120 "C. As second stage of the reaction vessel system became a tubular vessel in which held at the midpoint of the total temperature curve 180 "C and at the end point 210" C were used.

The reaction vessels were filled with propylene and cobalt 2-ethylhexoate as a catalyst in the ratio of 0.85 percent by weight calculated as cobalt metal, filled. The gas feed consisted of 50 weight percent carbon monoxide and 50 weight percent Weight percent hydrogen. It has been found that the product runs in this case primarily from n-butyl and isobutyl alcohols with less than 10 / o aldehydes duration.

Example 8 The reaction conditions and the procedure were the same the same as in Example 1, but a heptene fraction was used as starting material. The initial temperature was 120 "C, the mid-range temperature 190" C and the final temperature 210 "C.

The product consisted essentially entirely of isooctyl alcohols.

Example 9 The preparation of tridecyl alcohols was carried out by charging of the reaction system using the procedure of Example 1 with propylene tetramer carried out. The temperature profile that was obtained was similar to that of Example 1, and the products obtained were found to be essentially tridecyl alcohols with the production of only small amounts of tridecylaldehydes and paraffin hydrogen, was.

Example 10 A stirred autoclave was filled with 100 g of propylene tetramer and charged with a gas mixture of 40 percent by volume hydrogen and 60% carbon monoxide. Cobalt hydroxide was used as the catalyst component, which under the oxoation reaction conditions was converted to cobalt carboxyl. The reaction was initiated at approximately 120 "C and heating the entire reaction vessel to a maximum of about 210 ° C. To When the reaction was complete, the reaction vessel was cooled and the contents analyzed. It it was found that the reaction product consisted predominantly of tridecyl alcohol, only small amounts of tridecylaldehyde are present was. That Gas mixture present above the liquid reaction product was also analyzed and found it contained approximately 10,010 hydrogen based on total carbon monoxide plus available hydrogen.

Example 11 The procedure of Example 10 was followed with the addition of 10 ° lo water to the reaction mixture repeatedly. In this case the response was started at about 1000 C and held at about 120 "C during the reaction. It has been found that in such an essentially isothermal mode of operation virtually no alcohol production and very little conversion to propylene tetramer took place and the main product was tridecylaldehyde, the water in this experiment at a low temperature is therefore not an advantage.

Example 12 The procedure of Example 10 was followed with the modification carried out that 100 /, water added in addition to the liquid reaction charge became.

However, in this case the reaction was initiated at about 1500.degree and the temperature progression with a steadily increasing temperature, which is a maximum reached around 2100C.

It has been found that the products obtained are largely made from tridecyl alcohol passed with only small amounts of tridecylaldehyde present.

It was also found that the residues through the use decreased water and increased alcohol levels.

Claims (6)

Claims: 1. Process for the production of largely aldehyde-free Alcohols by the oxo process with conversion of olefins having 3 to 13 carbon atoms with carbon monoxide and hydrogen in the presence of catalysts, the reaction is carried out initially at a low temperature, then at a higher temperature, characterized in that the temperature is at an initial temperature of 50 to 1800C, over 180 to 200 "C in the middle range to a final temperature of 205 to 225" C respectively. 220 "C is increased during the reaction. 2. The method according to claim 1, characterized in that in one tubular reaction vessel is operated continuously, with the temperature profile is controlled continuously increasing over the length of the reaction vessel. 3. The method according to claim 1 and 2, characterized in that one an amount of hydrogen used at the inlet of the reaction vessel less than 60 ° lo and at the outlet less than 50% of the total volume of hydrogen and carbon monoxide amounts to. 4. The method according to claim 1 to 3, characterized in that one works in the presence of 0.2 to 10 percent by weight of water. 5. The method according to claim 1 to 4, characterized in that one Propylene trimer used as an olefin, the inlet temperature of the reaction mixture 100 to 178 "C and the hydrogen content at the inlet 60 to 40 01, and at the outlet is less than 20%, based on the total volume of hydrogen and carbon monoxide. 6. The method according to claim 1 to 4, characterized in that one Propylene is used as the olefin, the inlet temperature of the reaction mixture 100 to 140 "C. Considered publications: German Patent Specifications No. 921 934, 935 126, 888 094; Color sections of chemical research, 1951, vol. 2, p. 153.