BE642780A - - Google Patents

Description

       

   <Desc / Clms Page number 1>
 
 EMI1.1
 



  "Production of carboxylic acids *
 EMI1.2
 The present, inrention this relating to the. production of carboxylic acids. It relates more particularly to an improved two-phase process for ease of ole- reaction. fines with carbon monoxide and water in the presence of catalysts formed by mineral acids, in order to produce
 EMI1.3
 aliphatic carboxylic acids.
 EMI1.4
 



  The production of carboxylic acids from okfin 8, carbon monoxide and water, in the presence of a variety of acid catalysts, is well known. The process for producing carboxylic acids is well known. desired constitutes, for example, what C> F '& I should consider as being a process of synthesis in two

 <Desc / Clms Page number 2>

 
 EMI2.1
 phase, comprising the reaction of water, carbon monoxide to doldfines using a strong catalyst with a strongly acidic inorganic acid, such as boron fluoride hydrata.

   The reaction
 EMI2.2
 The basic principle of this process involves the combination of one mole of the olefinic feedstock with a cola of up to 9 mole of carbon monoxide to give the product formed by the carboxylic acid, and having one atom more carbon than a-
 EMI2.3
 olefinic feed. In the practice of this two-phase process, the first phase comprises reacting the key compound with carbon monoxide and the hydrated boron fluoride catalyst formed in the absence of any addition. of water. An exothermic reaction occurs with the formation of what may be called a catalyst complex of hydrated boron fluoride, carbon monoxide and the key compound.
 EMI2.4
 final.

   In the second phase of a two-phase process, it is then necessary to hydrolyze this complex using about one mole of water per mole of carbon monoxide in the complex.



  Although higher amounts of water can be used, this is not necessary and would require reconcentration.
 EMI2.5
 of the obtained dilute boron fluoride catalyst. It is in this second phase of the two-phase process that the invention particularly intervenes.



   Although the fundamental two-phase process is fundamentally interesting, the undue full possibilities
 EMI2.6
 Carboxylic acid production methods * from these relatively inexpensive reagents have generally not been used because of certain disadvantages involved in the previously proposed methods.

   By way of example, it has been found that if the stoichiometric molar amount 4 'or is added completely to the complex in a single hydrolysis phase, it is not possible to recover all of the fluoride catalysts of boron) only about 90 to 95 acid can
 EMI2.7
 IO. {Cup'r '. using this single hydrolysis phase.

   We

 <Desc / Clms Page number 3>

 found that, in a single hydrolysis phase, highly localized concentrates of water tend to dilute the liberated boron fluoride catalyst rather than hydrolyze the complex, so that incomplete hydrolysis occurs and that 'a relatively poor use of water results.

   Again, when synthesizing carboxylic acids having greater than about 7 carbon atoms, the boron fluoride catalyst is partially soluble in the carboxylic acid produced, so that complete recovery of the catalyst will not be achieved. cannot be carried out in a hydrolysis phase mold. It has also been found that when more than one hydrolysis step is used, if a sufficient excess of water is added to the hydrolysis slurry of the complex, solid boric acid will precipitate.

   On the other hand, if an insufficient amount of water is added to the hydrolytic acne, part of the complex will not be converted into this sone and solid boric acid will precipitate in the next washing zone.

   The precipitation of solid boric acid in the hydrolysis plant obstructs it and eventually renders it inoperative, causing expensive downtime for repairs *
In general, the present invention relates to the synthesis of the carboxylic acid by formation, in a first phase, of a complex of carbon monoxide, of a compound.

   key and of a catalyst consisting of hydrated boron fluoride, and by hydrolysis, constitute a second phase of the complex obtained, the improvement residing in the technique of hydrolysis of the complex in a hydrolysis phase. in several stages, in which at least one mole of water per mole of key compound of the complex is introduced in these stages, According to a preferred embodiment of the present invention,

     this multi-stage hydrolysis phase comprises at least three and preferably more than three separate stages In the first of these stages of the preferred embodiment, the complex is hydrolyzed with an aqueous hydrolysis medium to an acid mixture

 <Desc / Clms Page number 4>

 crude carboxylic acid product and dilute boron catalyst having
 EMI4.1
 a water / IF 3 ratio of less than about 3 / le In another of these distinct stages, different from the first and the last stages it is critical that the mixture of the crude carboxylic acid produced and the boron catalyst be diluted with an aqueous medium containing
 EMI4.2
 F'3, having a water / !?) molar ratio greater than a.

   15/1, a crude carboxylic acid produced and a reconstituted boron catalyst
 EMI4.3
 having a maximum water / Er3 molar ratio of about 3/1., In this or these later stage (s), the crude oarboxylic acid washes with the aqueous medium containing IF and this or ode and has 3, #. # ¯¯ ... '.: <4ir 14 t .....,; ... il .. 1 maintained at a molar ratio .a \ t / EP3 "' Pr: .., 'lVJJ' :; '-t .;' 1 '-' '#% - ..; ,,? ###' ït $ In general, the proceeds dt y, â "pieoiti ,; !,;.



  'in a general way ,. ":,. <., q, r y, .T¯.". r "-, .- 'yr' tion can be used for the preparation .4t '4e, f'; ti (.: starting from mono01't1 \ Ûe compounds: (iiô'bcÍiit1! iJ4 20 carbon atoms. elfinic feedstock can @@
 EMI4.4
 take straight or branched chain alkenes, including prepylene, butylene, pentene, and their higher counterparts, as well as the isomers of these alkeneao The olefins of this clan. terminal and internal unsaturated allenes may also form cyclic olefins having up to 20 carbon atoms may be used as feed, especially
 EMI4.5
 ..... cyclopentene, cyclohexene and their higher counterparts.

   1'tB- carries which desired mixture of these compounds, such as the C4 fraction recovered in petroleum refining operations, can be
 EMI4.6
 used, if desired. All of these aono-ol4f1n1qul8 compounds may contain functional groups, such as 4 # carboxylic acid, ester or alcohol groups.
The preferred catalyst for use in the process of the present invention is a fluorine catalyst.
 EMI4.7
 re hydrated boron, having the empirical formula 1! P3.xH20, where x is about 2 to 2.5.

   Such catalysts assume. r, y. , ¯! ,. ,,.> the combination or formation of a complex of fluOru'-r't '4 "8 boron with water, so as to form oompoa6é; o3n, tee .gitl 31GNA in particular those which correspond to the t qrmule): 1 '*: "" 1'- <' r .. '{":", ... <td (f .... :::. 1; "1.'; .tJ ',. t. t :: n¯f :: ':;';;.! t '} !. I, .. b

 <Desc / Clms Page number 5>

 'boron fluoride monohydrate and boron fluoride dihydrate, and which may include additional amounts of water which
 EMI5.1
 may be present as a solvent or may form a coma plex or otherwise react with boron fluoride in others.

   Such catalysts are referred to herein as "catalyst.
 EMI5.2
 boron fluoride oor hydrate *! Although various amounts of water can be used in such catalysts, it is especially preferred in the practice of the present invention.
 EMI5.3
 read a boron fluoride catalyst containing about 2 to 2.5 moles of water per mole of boron fluoride, and in particular a catalyst containing about 2 moles of water per mole of boron fluoride. Dn can use larger quantities of water, but this is not necessary and would involve additional complexities for the process with a view in particular to recovering or reconstituting the ,,
 EMI5.4
 desired catkoeur.

   Much smaller water contents are impractical because the hydrated boron fluoride catalyst cannot be recovered in the hydrolysis system of the invention, unless it is combined with about 1.7 to. 2 moles of water or slightly more.
 EMI5.5
 



  Optionally, however, boron fluoride hydrate catalyst can be employed in combination with other catalysts.
 EMI5.6
 lysers formed by inorganic acids. Sulfuric acid or phosphoric acid may in particular be usefully employed with the hydrous boron fluoride catalyst. The relative proportions of acids employed can vary, although the use; The use of approximately equal molar amounts of boron fluoride and phosphoric or sulfuric acid is preferred.
 EMI5.7
 



  The acid synthesis phase, i.e. the first phasen, can be carried out at temperatures on the order of about -2Q k i5O # Of although the preferred temperature is on the order of 20 h. ; 100eC. High pressures are required in order to maintain '., #', A high partial pressure of carbon monoxide. One can em ,, lo- 4 E p preseaione from 10 to 600 atmospheres or more, although one

 <Desc / Clms Page number 6>

   prefers to employ a pressure of about 40 to 100 atmospheres.



   The acid synthesis phase can be carried out continuously or discontinuously. In a batch process, the liquid catalyst formed by the inorganic acid is first introduced into a suitable reactor or autoolave, and then the carbon monoxide and the olefin are fed to this reactor continuously until the catalyst is exhausted. In the continuous process, a similar reactor and process can be used, but with continuous removal of reactants and continuous introduction of fresh or recycle catalyst.



   In general, the hydrolysis phase consists of the hydrolysis of the complex in a hydrolysis zone, so as to form the crude carboxylic acid constituting the product, followed by washing this crude acid in a are washing, these two zones comprising a series of continuous mixing-deposition stages a. against the current. In these stages, concentrations of HF3-water are maintained so as to avoid concentrations of HF3 in water, at which solid boric acid precipitates. Generally, the hydrolysis phase can be carried out at temperatures on the order of about to about 100 C, the preferred temperature range being 45 to 80 C.

   High pressures can be used, although this is not necessary
The invention will be further described with reference to the accompanying drawings.



   Figure 1 schematically illustrates the complete basic synthetic process.



   Figure 2 schematically illustrates a variant of the hydrolysis portion of the process illustrated in Figure 1.



   Figure 3 schematically illustrates the preferred complete embodiment of the synthesis process *
By first referring to Figure 1, reference 1 i- identifies the first stage reactor, in which the olefin is fed through line 2, carbon monoxide through line 3

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      and the boron fluoride catalyst hydrated through line 4. The
 EMI7.1
 The reactor is equipped with a stirring device 5, so as to thoroughly agitate the contents of the reactor and to maintain a good mixture! 1Logne.



  The reaction of olefin, carbon monoxide and oa-
 EMI7.2
 tal.yseur in 3a reactor 1 is carried out at a temperature of the order of -20 to 150'0 under a carbon monoxide pressure of about
 EMI7.3
 20 to 600 atmospheres. It is preferred to use long reaction periods of about 1 to 4 hours, so as to achieve a conversion.
 EMI7.4
 Complete elimination of the oldfinic or complex feed with carbon monoxide and boron fluoride catalyst.

   Nature preci-
 EMI7.5
 of the complex is not fully understood by hand this complex exiles us as a homogeneous liquid, containing precursors of the final carboxylic acid which is produced or maintaining this carboxylic acid in a kind of complex formation with boron fluoride. The reaction described to form this complex this'
 EMI7.6
 carried out with about 0.5 to 1.5 soles of catalyst per mole of ol6ic feed. Preferably, a substantial excess of the catalyst is maintained over the amount which is involved in a complex with the olefin. j
According to the present invention, the complex described is subjected to the treatment phases illustrated in the drawing.

   In the
 EMI7.7
 first phase of the proodddg the @ engine product are removed from reactor 1 through line 6 and are mixed with a hydrocarbon diluent to allow separation of the catalyst exoee
 EMI7.8
 at. starting from the complex forms during the reaction. This can be achieved by using a simple orifice mixer, with the addition of a deposit tank. Or, as illustrated in Figure 1, the hydrocarbon diluent can be mixed with the products of
 EMI7.9
 reactor in a mixing and settling tank 7.

   We can in- $; troduiro into reservoir 7 through line 8, a naphtha or other hydrocarbon diluent, such as non-liquid paraffins. 18 anite: normally liquid, low molecular weight, for mixing.

 <Desc / Clms Page number 8>

 
 EMI8.1
 5v with the products of the reactor in the stirred teae 9.

   Preferably about 15-20% by volume of the hydrocarbon diluent is used, although any desired amount can be used. The mixture can then overflow above weir 10 into the deposit area 11 to allow separating a lower catalyst phase 12 having an intermediate surface in the sump portion of the mixing and settling tank. The separated catalyst can be removed through line 13 for its
 EMI8.2
 recycling and reuse in the rfaotr..1 7 - J -, ('os ...' ..:;.

   J '! T, .. 1 .. ... "l'. R According to the present 1n" eAtj.ot U 00 *, 11 ':' ,, "." ":. ' 4r tien of the excess decides golden horn, jetos k'.ûtt * treatment: '/' - \ - 'rx: ¯,:. "1" "" 1' \. '; Hydrolysis at several stages in * 1i4.ir> ri, r .goyidèe .1.:.! 1 ((\ - / 11t; ..: w.,. It.;: -, ..tfJ'.ei. K mixer and depositing device .14,, 15 and 16. Referring to the hydrolysis zone 14 for example,, 4e 'water intxoduie' ar, 1, J '"..; .. r' ¯ .... 1 The complex introduced into the mixture via line 18. The mixture of water and complex is mixed in zone 20 and there is a mixture of water and complex. is then subjected to deposition in zone 21 to allow separation of the catalyst as an interior phase and its removal through line 22.

   The separate complex is then sent through line 23 for mixing.
 EMI8.3
 with additional water added to vessel 15 through line 24. Again, the separated catalyst is removed through line 25 and the remaining organic material is removed from the tank. see 15 through line 26 for introduction into hydrolysis tank 16. Water is similarly added to tank 16 through line 27, and the catalyst is recovered from there. the deposit part of this reactor 16 via line 28.



   The catalyst recovered from lines 13, 22, 25 and 28 can be recycled and returned to reactor 1. The remaining organic material, in the last hydrolysis zone 16, is removed by the reactor.
 EMI8.4
 conduit 29 and introduced into a zone 4: '1â'; "; Íiè'a -" '3 + tj ;. ± # * '. - / 4y Y. i, 7 product is washed with water so as to ext¯rairlei: t.oit.:) ..;. 1.: ..



  '- / fJ ---'.

 <Desc / Clms Page number 9>

 rer of the carboxylic acid produced, any * remaining traces of the boron fluoride catalyst. Any desired water washing arrangement can be said to be employed for this purpose, although it is desirable to provide at least about ten stages of contact.



   As shown in the drawing, this can be done in a water wash vertical 30, in which water is introduced at the top through line 31 for counter-current circulation. by gravity with the carboxylic acid introduced at the bottom of the tower. Tower 30 may be provided with stuffing material 32 and may include agitation devices in areas between the separate fodder for the purpose of an effective countercurrent contact mine in several stages. The washed product carboxylic acid can then be removed from the tower through line 33.

   This process product can then be subjected to fractionation or other desired finishing and purification steps.



   The water removed from the bottom of tower 30 through line 34 will contain the recovered boron fluoride catalyst. This water is therefore used to meet the hydrolysis requirements of hydrolysis zones 14, 15 and 16, ensuring complete retention of all boron fluoride catalyst in the system described.



   As noted, in an equilibrium operation, at least one mole of water should be introduced through line 31 and then used in the hydrolysis phases of the process for each mole of carboxylic acid produced. the distribution of the amount of water in the three hydrolysis sections 14, 15 and 16 is not particularly critical and approximately equal proportions * of water can be supplied to each of these hydrolysis zones *
In the mixing phase, it is necessary to ensure proper mixing of the complex in the hydrolysis medium.

   This is advantageously achieved by employing fairly moderate stirring for about five minutes an hour, to achieve equilibrium hydrolysis conditions. Then the carboxy-

 <Desc / Clms Page number 10>

   The product can be separated in a quiet deposition area, using a deposition period of up to about one hour. Particularly when an inert paraffinic diluent, as described, is used in the procedure, the deposition is easily accomplished & deposition rates of about one inch per minute.

   In general, the described process can be designed to provide combined periods of retention in the mixing and settling zones, of about one hour, for each hydrolysis stage.



   It is important that the hydrolysis be carried out at a temperature below about 150 ° C. The hydrolysis can then be carried out at room temperatures, although cooling devices can be used between stages, if necessary, to keep the temperature below 150 F at all times, and to keep the temperature below 150 F at all times. compensate for the heat of reaction due to. hydrolysis.



   Figure 2 of the drawings shows an embodiment of the invention, specially adapted for the production of arbexylic acids having more than about seven carbon atoms. Such high molecular weight carboxylic acids can dissolve large amounts of the boron fluoride catalyst up to about 10 by weight. The variation of Figure 2 of the drawings is especially advantageous as a means to improve the separation of the acid catalyst from the produced carboxylic acid.



   To refer at. FIG. 2, the line 50 corresponds to the line 18 of FIG. 1 and is used to introduce the complex to be hydrolyzed into a first hydrolysis zone 51. The complex is hydrolysed in this zone 51 with a dilute boron fluoride catalyst, recovered as described below and fed into hydrolysis zone 51 through line 52. Hydrolysis of the complex in zone 51 results in the separation of the boron fluoride catalyst for non-removal by the) AIGINAL leads 53 and its return to reactor 1. The complex is removed

 <Desc / Clms Page number 11>

 reservoir 51 via line 54 and sent to the second hydrolysis zone 55 where it is mixed with water introduced * via line 56.

   Again, the acid separated as a result of this hydrolysis can be recovered through line 57 for recycling to rotator 1. The upper complex phase, separated from the catalyst, and removed from zone 55 by conduit 58 with a view to its introduction into the third hydrolysis phase 59 and its mixing with additional water introduced via conduit 60.



   The operation such that the hydrolysis of the complex is completed - and the separated carboxylic acid is washed with water in the zone
59, so as to separate substantially all of the catalyst from the carboxylic acid. This catalyst is separated from the carboxylic acid in the deposit 61 for the purpose of removing the catalyst separated by the sump portion 62 and for its recycling to the hydrolysis zone 51 through line 52.

   The separated carboxylic acid can be removed through line 63 and sent to a product distillation and finishing stage, or it can first be subjected preferably to an additional water wash, as described. with reference to FIG. 1. In the case where an additional washing with water is used, the water used in this phase is recovered with a view to not introducing through the line 64 and for its use in the hydrolysis zones 55 and 59.



   In the use of the product described in FIG. 2, for operation in equilibrium, one mole of water for each mole of carboxylic acid produced will be introduced through line 64.



   Preferably, most of this water will pass through conduit 60 and aera used in hydrolysis zone 59, the remaining small portion of water being sent through conduit 56 and used in the hydrolysis zone. hydrolysis 55.

   Thus, it is preferred that about 75% of the total hydrolyzed water is used in the last hydrolysis phase (tank 59) while about 25% of the water is used in the second. hydrolysis phase (reservoir

 <Desc / Clms Page number 12>

   55). When done in this manner, the acid catalyst recovered from hydrolysis zone 59 will be diluted with water to form a composition containing about 2 to 4 moles more water per mole of boron fluoride. This composition can best be described as constituting a dilute solution of boron fluoride and its hydrolysis products.

   As illustrated in FIG. 2 of the drawings, it is this dilute solution of boron fluoride which is actually used to ensure the hydrolysis of the complex in the first hydrolysis sounder 51. Optionally, however, the dilute solution of Boron fluoride can be recycled in parts to the second phase of hydrolysis, as well as to the first phase of hydrolysis.



   Figure 3 of the drawings shows a preferred embodiment of the invention.



   Referring to Figure 3, numeral 71 identifies the first phase reactor in which the olefin is supplied through line 72, carbon monoxide through line 73, and hydrated boron fluoride catalyst. via line 74. The reactor, which is preferably a spherical tank, is equipped with a stirring device 75 in order to thoroughly agitate the contents of the reactor and to maintain a homogeneous mixture *
The reaction of the olefin, carbon monoxide and catalyst in reactor 71 is carried out at a temperature of the order of -20 to 150 ° C. under a carbon monoxide pressure of about 10 to. 600 atmospheres.

   It is preferred to use long reaction periods of about 1 to 4 hours in order to achieve maximum conversion of the olefinic feed to complex with carbon monoxide and boron fluoride catalyst. It is believed that the nature of the complex is such that this complex exists forms a homogeneous liquid containing precursors of the final carboxylic acid to be produced or now this carboxylic acid produced by some type of fermentation of . complex with boron fluoride.

   The reaction described can form this complex

 <Desc / Clms Page number 13>

 
 EMI13.1
 From about z to 1.5 moles of catalyst per mole of final feed. A large excess is preferably maintained. so much catalyst compared to the quantity which is
 EMI13.2
 a complex with elfin.



   According to this embodiment of the invention, the described complex is subjected to the processing steps illustrated by the drawing. In the first phase of the production, the products of the reactor are removed from this reactor 71 through line 76 and mixed with a hydrocarbon diluent to allow the separation of excess catalyst from the complex.
 EMI13.3
 - '* fomd during the reaction. This can be achieved by using a m4, iangour'k orifice followed by a deposit tank.

   Or, as illustrated in Figure 3, the hydrocarbon diluent can be mixed with the reactor products in a mixing and deposition tank 77. A naphtha or other hydrocarbon diluent, such as non-reactivated, normally liquid, low paraffins. molecular weight, can be introduced into tank 77 through line 78 for mixing with reactor products
 EMI13.4
 : '' in a agitated zone 79, preferably about 15 to 3 are used;

  20 by volume of the hydrocarbon diluent, although 0 or 0 atimport -0 is paid as desired. this mixture can then overflow through the dam 80 into the deposition zone 81 to allow the separation of a lower phase of catalyst 82 ci 4 /, -; 'having an intermediate urtace in the thick sard portion of the mixing and settling tank. The separated catalyst can be removed through line 83 for recycling and reuse in reactor 71.



   According to this embodiment of the invention, the complex, after separation of the excess acid as described, is
 EMI13.5
 eoumia a. hydrolysis treatment in a multiply spread hydrolysis phase. Such a hydrolysis treatment is suitably carried out in a continuous countercurrent vertical hydrolysis tower 84.

   In applying this form of re-
 EMI13.6
 @@ ation to this tower, conditions are maintained in such

 <Desc / Clms Page number 14>

 
 EMI14.1
 so that this lour is divided into 4 which one can call phases or zones, o'eet-h4ire a first zone 84'hT4rol1 "of complexent in which the catalyst phase is continuous and
 EMI14.2
 the complex is dispersed, and a second washing zone dlaolde * g in which the. the aid phase has continued and the water is dispersed.



   In practice, the complex hydrolysis zone is characterized as being of a generally dark color and the acid washing zone as being of a light color. As mentioned pre-
 EMI14.3
 edemmeat, the tower in which the hydrolysis phase is carried out and contains a separate mixing / settling stage; Thus, each of the complex hydrolysis and acid washing zones contains one or more stages, the number of these stages depending on a series of variables used in the process, namely the flow rate. , temperature, etc.

   As used
 EMI14.4
 here, the term "stage", although a different stage of mixing and settling is described, need not be limited to a stage where free equi is necessarily reached and, therefore, this term need not be limited. be limited to an ideal * or "theoretical * stage. However, it has been found that, relative to the conditions employed here, a minimum of three stages is contained in tower 84, one se *
 EMI14.5
 Since 3 to 16 stages are considered suitable, these stages being the preferred number.

   Of this number of stages, one or more will form hydrolysis stages in the complex hydrolysis area, one stage will be what will be referred to as the "dilution stage" of the hydrolysis phase. and one or more stages will constitute wash stages in the acid wash zone. The residence times in each of these stages range from 5 to 120 minutes, so as to achieve complete mixing and deposition. hydrolysis tower 84 is mine in operation
 EMI14.6
 temperatures of the order of 30 to c, preferably of the order of 45 to 80 C.

   If desired, cooling sprays can be provided in the hydrolysis zone of the tower.

 <Desc / Clms Page number 15>

 to remove the heat of reaction resulting from this zone. Well
 EMI15.1
 that one can provide a jam in the washing area of Aei-j of, o'et-è4 that is to say the upper stages of the tower, so as to help the dhp8tg a jam is not advantageous in the area dt hydrolysis, 3rd which thus allows the tower to be auscepti monk.

   wheat of an obstruction in the event of the formation of solid oidqur acid during an upheaval,
In the process of the present invention, the complex 'is fed to a first hydrolysis stage, rich in catalyst,
 EMI15.2
 located at the bottom of the hydrolysis tower 84, and through a conduit 85, and water, where the condensate from the water wash tower 86, was supplied at the omet of the turn 84 through conduit 67.

   The interior portion of the tower (for example the ten sta. Of the lower A in a tower 1 be @ stages) is used
 EMI15.3
 mainly for the hydrolysis of the complex # as mentioned, in this zone of the hydrolysis tower the catalyst phase is continued and the complex is dispersed, The complex, that is;
 EMI15.4
 As the catalyst, dense monk rises through the catalyst in this tower eone and is hydrolyzed with intimate contact with the catalyst which has been somewhat diluted by the condensate water from the top.

   Therefore, in this area, the
 EMI15.5
 complex reacts with an ateechmetric amount of water to close the carboxylic acid and release the hydrated HF3 catalyst.



  At the last stage of hydrolysis of the hydrolysis sone of the tower,
 EMI15.6
 the molar ratio of water to 8g3 contained in the atexce stage is 3/1 step and is generally about 2 to 3/1. ,
 EMI15.7
 Since the last stage of the hydrolysis zone, the ao1-J l of practically hydrolyzed containing a certain amount of
 EMI15.8
 173, 'Removes in the tower in the separate equilibrium dilution stage of this hydrolysis material.
 EMI15.9
 



  Without the dilution step, the condensate water containing 3 in an amount such that the molar ratio FI20 / BF) is greater than 15/1 from the top and is m6lan-] # *.



  NAL6e intimately with the rising catalyst and the NAL oompoaantaj

 <Desc / Clms Page number 16>

 acids contained in it. The mixture was kept in this separate stage for a time sufficient so that the molar water / HF3 ratio contained in this stage was about 3/1 or less.



   The hydrolyzed crude aarboxylic acid, still containing a certain quantity of HF3, continues on its ascent in the hydrolysis tower and enters the upper stages remaining @ of the tower, i.e. the B stages which are calls acid wash zone. In this zone, the acid is washed by the oondeneat water which has been supplied, as mentioned, to the top of the hydrolysis tower via line 67.

   In this portion of the tower, the acid phase is continuous and the water is dispersed. Here, there. The washed crude carboxylic product produced is removed from the top of the hydrolysis tower through line 88 and the catalyst is removed from the bottom of the tower through line 89, which catalyst can be recycled and returned to reactor 1.



   As can be understood, the amount of condensate water added to the hydrolysis tower is critical for the present invention. If we add too much, the. water, the recovered catalyst will be diluted. Additionally, if sufficient excess water is added to the hydrolysis zone in the tower so as to increase the. water content of the catalyst in excess HF3.3 H2O, but below HF3. H2O, solid boric acid will precipitate. Conversely, if an insufficient amount of water is added to the hydrolysis zone, part of the complex will not be converted in this hydrolysis zone and the salid boric acid will precipitate later in the zone. acid wash.

   It is therefore preferred, therefore, to provide instruments based on specific gravity so as to control the water: HF3 molar ratio and thereby control the rate of water addition.



  Experience has shown that the specific gravities which can be tolerated in the various parts of the hydrolysis tower without precipitation of boric acid are as follows: 1

 <Desc / Clms Page number 17>

 
 EMI17.1
 Zone Molar ratio Specific weight at 24.0; z¯¯¯¯¯¯ 20 3
 EMI17.2
 
<tb> Hydrolysis
<tb>
 
 EMI17.3
 (a) se Hydrolyte stages- <.3.0 1> 1.49 (b) Dilution stage -3.0 to 1 or less ^ -1.49 or more acid wash> 15.0 1.15
 EMI17.4
 Obviously, filters are preferably provided at suitable places in the hydrolysis tower to remove traces of solid boric acid which might form during the process.
 EMI17.5
 some upheaval.

   Likewise, the catalyst can be recycled either from the bottom of the tower, or from a
 EMI17.6
 another place in the system to the hydrolysis zone of this heifer This process allows the molar ratio to be quickly adjusted
 EMI17.7
 water / IF3 of the catalyst to bring it into the desired range of less than about 2.5 / 1, if the catalyst becomes too dilute.



   The partially washed carboxylic acid flows from the top of the hydrolysis tower 84 to the end of the la- tower. flow to water 86 via conduit 88, in which the remaining traces of the boron fluoride catalyst are removed. A steam condensate, such as water, is preferably used for washing. Any water wash arrangement
 EMI17.8
 can be used for this purpose, bierquil is preferable to provide the monk about 80 stages of cantact.

   As illustrated in Fig. 3, this can be done in a vertical water wash tower 86, into which water is introduced through line 90 for counter-gravity circulation. current with the crude carboxylic acid introduced at the bottom of the tower. Tower 86 may be provided with a stuffing material as well as agitation devices in areas between the separate stuffs, in order to achieve effective multi-stage countercurrent contact.

   The washed carboxylic acid can then be removed from the tower through line 91.
 EMI17.9
 This product of the process can then be subjected to a fraotioane-

 <Desc / Clms Page number 18>

 ment or other desired purification and finishing stages.



     The water removed from the bottom of tower 86 through line 87 will contain the recovered boron fluoride catalyst. This water is, therefore, used to meet the hydrolysis requirements of hydrolysis tower 84, ensuring complete retention of all of the boron fluoride catalyst in the disclosed system.



   As indicated, in an equilibrium operation, at least one mole of water must be introduced through the pipe 90 and subsequently used in the hydrolysis phases of the process for each mole of carboxylic acid produced. The distribution of the amount of water in the entire acid washing, dilution and hydrolysis stages, however, is especially critical in this embodiment and the water must be mounted at each of the stages, as is done. described it above.



   EXAMPLE 1
In a first experiment, a C9 olefin constituting a propylene trimer was reacted with carbon monoxide and a catalyst formed by HF3.2 H2O. The complex was formed at a temperature of about 125 F at a carbon monoxide pressure of about 1500 pounds per square inch, using an excess of the boron fluoride dihydrate catalyst. The complex formed is allowed to deposit for several days at room temperatures, and an unreacted calalyzer phase is formed and removed under the denser layer. Then the remaining complex is heated to about 130 F and allowed to stand.

   Under these conditions, no further recovery of catalyst is obtained. However, when 500 grams of the homogeneous acid complex is mixed with about 70 grams of a C7 parffinic fraction, and left to settle for about an hour at 130 F, 13.6 grams of the catalyst. HF3.2 H2O

 <Desc / Clms Page number 19>

 separate as the heaviest phase. This example shows * therefore, the improvement that can be obtained in the de-
 EMI19.1
 p8t using a paralfinic diluent as described.



  In a second experiment, world to demonstrate the
 EMI19.2
 Operability of the Hydrolysis System Shown in Figure 1 of the drawings, a complex was formed with isobut71ene, carbon monoxide and a BF3.2 H2O catalyst. The reactor effluent from the complex formation phase was then diluted with about 10% by weight normal hexane, and the
 EMI19.3
 Excess unreacted catalyst 12342 R20 is allowed to settle and is removed * The remaining complex is then hydrolyzed in three phases using water which has been used to wash an equivalent amount of resulting crude acid of such hydrolysis.

   Thus, the hydrolysis water used was mine stripped in contact with crude carboxylic acid in three stages of equilibrium. This water was found to have a pH below 1, indicating the presence of small amounts of HF3 and /
 EMI19.4
 or of its hydrolysis products. The weight of the hydrolysis water used represents a 10 mole% excess over the amount required to hydrolyze the complex.

     The hydrolysis is this batchwise * in three separate stages? by employing a five minute mixing period and a 15 minute settling period in each stage. The boron fluid rare catalyst resulting from hydrolysis is separated in each stage. After adjustment for excess water added during hydra-
 EMI19.5
 lysis, the weight B 2 302 H 2 O recovered is equal to that loaded as a complex.

   The acid recovered is then recycled to the µva stage. thesis and finds that the catalyst has the same activity and
 EMI19.6
 same flexibility as catalyst IV302 a2O.fait.



   In a similar manner, a dilute regenerated HF3 catalyst was prepared, this catalyst having the composition HF3.
 EMI19.7
 820. 100 grammee of the complex formed by reaction with a trimera 'of prepylene, carbon monoxide and 3.2 920 (free of

 <Desc / Clms Page number 20>

 excess HF3.2 H2O catalyst) were diluted with about 10% by weight of a C7 paraffinic naphtha fraction, and the excess unreacted HF3.2 H2O * catalyst allowed to deposit and was removed. The remaining complex is then mixed with 7.6 grams of the diluted regenerated catalyst.

   On standing, the mixture gives 11.1 grams of hydrated boron fluoride catalyst suitable for direct reuse in the synthesis phase. This example therefore shows the operability of using a diluted regenerated catalyst for. hydrolyzing the complex of carbon monoxide, olefin and catalyst.



     EXAMPLE 2
In a world experiment to demonstrate the operative nature of the hydrolysis system shown in figure) of des. Thus, a complex was formed with a propylene trimer, carbon monoxide and an HF3.2 H2O catalyst. The reactor effluent from the complex formation phase was then diluted to about 15% by volume normal hexane, and the catalyst HF3.



  2 H2O in excess, unreacted, was allowed to deposit and was removed. the remaining complex is then hydrolyzed in stages at a tower temperature of about 75 ° C., using water which has been used to worm an equivalent amount of crude acid resulting from this hydrolysis. Thus the hydrolysis water used was obtained by mining in contact with crude carboxylic acid in equilibrium stages. Small quantities of solid boric acid are taken along with the organic acid product C10. There is no evidence of solid beric acid formation in the column itself. The washed organic acid has a pH of 4, indicating good washing.



   The regenerated catalyst has a specific gravity of 1.61-27 C.



   It has been found that the recovered acid is suitable for recycling to the synthesis phase, apparently with the same activity and the same selectivity as said HF3 catalyst. 2 H2O spawns.

** ATTENTION ** end of DESC field can contain start of CLMS **.


    

Claims (1)

CLAIMS 1. A process for the synthesis of carboxylic acids by = <Desc / Clms Page number 21> a formation, constituting a first phase, of a complex of carbon monoxide, of a key compound and of a catalyst constituted by hydrated boron fluoride, and by hydrolysis, constitute a second phase, of this complex, a process comprising the hydrolysis of the complex in a series of stages in which at least one mole of water per mole of keyfinic compound of the complex is introduced in these stages. 2. A process according to claim 1, wherein carbon monoxide, a key compound and a hydrous boron fluoride catalyst are reacted at a temperature of -20 150 ° 0 and a pressure of 10 to 600. atmospheres * 3. A process according to claim 1 wherein the complex separates from excess catalyst by admixing with an amount of up to about 25 by volume of a liquid, non-reactive hydrocarbon diluent. 4. A process according to claim 1, wherein the complex is hydrolyzed with an aqueous hydrolysis medium. ' 5. A process according to any preceding claim, wherein the complex is mixed with an aqueous hydrolysis medium in the first hydrolysis stage and a first stream of carboxylic acid produced and a first stream, of recovered catalyst are separated from the mixture, the first stream of carboxylic acid produced mixed with an aqueous hydrolysis medium in at least one additional hydrolysis step, and a second stream of product carboxylic acid and a second stream of recovered catalyst are separated from the mixture, and the first and second stream of recovered catalyst are recycled to the first phase of the process. 6. A process according to claim 5, wherein the second decided carboxylic stream produced is mixed with water and then an aqueous medium is separated from the mixture and is employed as an aqueous hydrolysis medium. 7. A precedent according to claims 1 to 4, in the- <Desc / Clms Page number 22> where the complex is introduced into at least one separate hydrolysis otad, the complex is hydrolyzed therein with an aqueous hydrolysis medium to a crude carboxylic acid and a reconstituted boron catalyst having a water / HF3 molar ratio less than 3/1, the resulting catalyst-acid product mixture is introduced into a further separate stage, the catalyst-acid product mixture is diluted with an aqueous medium containing HF3, having a water / HF3 molar ratio of greater than 15 / 1, while this stage is maintained in equilibrium and at a water / HF3 molar ratio of approximately 3/1 male below this figure, the resulting acidic catalyst-product mixture is introduced into at least one further stage, and the catalyst-acidic product mixture is washed with an aqueous medium, while the stage is maintained at a water / HF3 molar ratio greater than 15. / 1. 8. A process according to claim 7, wherein, prior to hydrolysis, the complex is separated from the excess catalyst by mixing with an amount of up to about 25% by volume of a liquid hydrocarbon diluent, not. reagent. 9. A process according to either of Claims 7 or 8, wherein the complex is continuously hydrolyzed in a hydrolysis tower having a minimum of three separate mixing and settling stages, the complex have hydrolyzed in one of these steps with an aqueous hydrolysis medium to a crude carboxylic acid product and dilute boron catalyst having a water / HF3 molar ratio of less than about 3/1, A process in which also , in one of the stages, other than a first stage and a last stage, and following a hydrolyte stage, the carboxylic acid produced and a reconstituted boron catalyst having a water / 29 molar ratio of less than about 3/1 are diluted with an aqueous medium having a water / @@ 3 molar ratio greater than 15/1, to a carboxylic acid crude and a more dilute bors @@@ titled catalyst having a water / HF3 molar ratio of about 3/1, but lower than these ciphers proceed in which also EMI22.1 urartu-tt @ crude carboxylic acid <Desc / Clms Page number 23> EMI23.1 from the dilution stage, washed with an aqueous medium having a solar water / HF3 ratio greater than 15/1. EMI23.2 10. A process according to any one of the following steps 7 to 9, wherein the complex has been hydrolyzed in a hydrolysis tower having 16 separate stages, a first part of the stages comprising 9. of this = -ci in which EMI23.3 the complex is hydrolyzed with a countercurrent circulation of an aqueous 4t11141'o17l 'medium, into a crude carboxylic acid and reconstituted boron catalyst having a solar water / water ratio. EMI23.4 8P'3 less than 3/1, a second portion of the stages consisting of a single, distinct, equilibrium stage in which the acid produced and the catalyst are diluted with counter circulation. raat of an aqueous hydrolysis medium containing from to? 3 "O a ratio to. / 5 '3 greater than 15/1, in a crude carboxylic acid and EMI23.5 in reconstituted boron oatal1leur having a water / Pl3 molar ratio of 3/1, and a third portion 489 .tad. o comprising six eta dee o4p <tr <! <, in which the product acid and catalyst have been washed and further diluted with the countercurrent flow of aqueous hydrolysis medium ocontaining BP3t to a crude oarboxylic acid produced and reconstituted boron catalyst having a EMI23.6 water / M? 3 molar ratio greater than 15 / lt and recovery of the product carboxylic acid and the resulting dilute boron fluoride catalyst. 11. A method according to claim 10, wherein EMI23.7 the hydrolysis tower is mined in operation at temperatures of 30%. 10000s 12. A process according to claim 11, in which residence times of 5 to 120 minutes are used, EMI23.8 13. A process for the synthesis of aoid.8 carboxyliquest as described above in particular in the examples given. 14. Carboxylic acids when obtained by a process according to any one of the preceding claims.