CS195296B2 - Method of making the powder-like carriers of catalysers from the silicic acid or catalyser from the palladium and silicic acid - Google Patents

Abstract

1503642 Catalytic reactions HOECHST AG 2 July 1975 [6 July 1974] 27838/75 Heading B1F In the process for carrying out heterogeneous catalytic reactions continuously in liquid phase as disclosed in specification 1363245. the catalyst is a palladium catalyst deposited on a silica carrier which is obtained by contacting a mixture of pulverulent silica carrier and in homogeneous silica particles with upward flowing water to free the carrier from the silica particles. The expression "inhomogeneous silica particles" is defined as meaning silica particles having a porosity which differs substantially from that of the other particles in the mixture. Such particles consist mainly of the fines present in the mixture. The silica carrier has a particle size of 20-300 microns and the catalyst may be produced by impregnating the carrier with a palladium salt which is subsequently reduced to metallic palladium in accordance with the process described in Specification 1403293.

Description

(54) A method for producing a pulverulent support of a catalyst from silicic acid or catalysts from palladium and silicic acid

BACKGROUND OF THE INVENTION The present invention relates to a process for the production of pulverized silica support catalysts or palladium catalysts and silicic acid catalysts for spray-dried liquid phase reactions.

DE-DOS 2 053 115 describes a process for continuously carrying out heterogeneous liquid phase liquid phase catalytic reactions in a fluidized bed, wherein the suspension of liquid starting material and catalyst, together with the reaction product being formed, is continuously passed through a circuit which continuously separates the reaction product in the deposition reaction. A new starting material is fed continuously from the catalyst slurry and the remaining catalyst slurry.

According to the drawing, the process according to DOS No. 2,053,115 is characterized in detail in that the homogeneous suspension of liquid starting material and fine-grained catalyst with the introduction of gas or steam to the bottom of the reaction zone 1 leads continuously along the reaction product. in the deposition zone 2 formed in the manner of the injector system, a portion of the reaction product is continuously separated from the suspension and an aliquot part of the new starting material is continuously supplied to the remaining suspension, while in the deposition zone 2 the flow rate than the sedimentation rate of the catalyst in suspension. The reaction product taken from the deposition zone 2 can be stripped of any catalyst particles in the filter device 4, for example filter candles, and the filtered catalyst is returned to the reaction zone 1. The principle of continuous removal of pure reaction liquid product from the catalyst slurry is the specific mass between the catalyst and the reaction product within the virtually no-flow exclusion zone 2, also at the suction of the downstream injector system 5.

However, it has been shown that inhomogeneous particles in the pulverulent catalyst can substantially interfere with the operation of the fluidized bed or fluidized bed in the liquid phase. Inhomogeneous particles are to be understood, for example, to be non-compact hollow particles which substantially deviate in their porous structure from most other particles. Such inhomogeneous particles, which, due to their small dimensions, form a predominantly fine component of the pulverulent catalyst, bind air bubbles to each other and consequently have a different sedimentation behavior. As a result, the intended separation of ka195296 can be substantially impeded

5'2'9 β-palladium-crude product from the catalyst slurry. The aforementioned drawbacks are overcome by the method according to the invention, characterized in that inhomogeneous particles of the catalyst carrier or catalyst are washed out in a liquid flowing upwards according to the principle of countercurrent sorting, wherein the liquid velocity flowing upwards is at least as high as the rate of removal of the product from the sedimentation zone when carrying out catalytic reactions in the fluidized bed in the liquid phase. .

It is also a feature of the present invention that the catalyst support particles or catalyst particles have a diameter of 20.10 ^-6 m to 2.10 ⁵ m. The last feature is that the upwardly flowing liquid is water.

The invention will now be explained in more detail using the example of hydrated dehalogenation of dichloroacetic acid. to monochloroacetic acid in the presence of palladium JaRp on a SiO2 support. The catalyst can be produced, for example, in the manner described in U.S. Pat. No. 2,424,444 by impregnating silica as a support with palladium salts and, for this, by reducing the palladium metal. Due to the aggressiveness of the chloroacetic acid and the required mechanical stability of the catalyst, in this particular case only silicon dioxide is used as the carrier material and only spray drying as the production method. During spray drying, a carrier material having a grain size of 20 to 300-10 m is whistled. The analysis can be seen from Table 1. If a carrier with this grain spectrum is produced according to the method of DOS 2- 240 The 466 palladium catalyst and, if used for the hydrogenation de-acidification of the acid according to the method described in U.S. Pat. ® kMpru including yylation zone 3 at most 15 kg of catalyst · At higher - Catalyst content per W? Cause of downtime is not the functional capability of the method of action. .Katalyzátor in -tomto - case peusuzuje exclusionary zone 2, but the filter .ae -jukiádá - candlelight 4 - to ^the fast that - not with ^e - ^ et .w to anomalous operating '-podmínky. Since the reaction is far-reaching in a palladium metal surface, the amount of catalyst per volume unit determines the capacity of the apparatus.

Surprisingly, it has been found that the catalyst content per m < 2 > of reactivity can be substantially increased by influencing the rated capability of the layer if it has removed some of the fine components of the catalyst mass. This measure can decisively increase the yield of the fluidized bed both in terms of space and time. It has, however, been shown that separation methods, as are conventional in the art, such as screening for air separation, do not provide liquid catalysts or catalyst supports for the fluidized bed. Because the functional capacity of the fluidized bed in the liquid phase is larger than average, but also has a particular catalyst side, it cannot be obtained with these separation methods. optimal catalysts for fluid phase in the liquid phase. .

In finding a suitable solution, it has been found that the catalyst, which can be used in the fluidized bed in the liquid phase, can be obtained in a very simple manner if the inhomogeneous catalyst support or catalyst particles are leached out to the liquid. upstream, according to the principle of countercurrent sorting. By virtue of the free velocities of the liquids flowing upwards as well as the selection of a sufficient specific gravity difference of the solids (catalyst carrier, catalyst) and the liquid suspensions, the catalyst supports can be obtained in the form of a solid catalyst carrier. or " optimum particle size distribution catalysts " for reaction in the fluidized bed in the liquid phase. It is also possible to use, as a suspending liquid, local water, for example, organic liquids, if a larger specific weight difference is to be achieved. On the other hand, it may also be desirable to replace the suspension liquid if water would dissolve a portion of the countercurrent sorted catalyst. It is not possible to specify a specific speed range or the required specific weight difference. These values can be determined by a simple experiment by each / expert case by case.

Example 1

A 3.5 m high pellet with a diameter of 200 mm is filled to about half a height of 54 liters of silicon dioxide Ш10М as carrier, coated with drying (granularity of this classified carrier), Table 1. At the lower end of the pipe, -35-100 h of water is supplied, the OSZ corresponds to a velocity of -0.3 m / sec. At this speed, upwards ^{, the} entire mass of the carrier is maintained in the suspension state, and only certain fine particles are carried away at the outlet at the upper end of the tube. Asia after 2 hours It is invented inhomogeneous. - carrier part finished. This moment can be recognized by the fact that the effluent no longer contains any carrier material. The deposited material is filtered out and fed in, resp. other use. The material remaining in the tube is collected through a filter device and used to produce the catalyst. in this mode of operation, 12% of the leached material is obtained in a proportion of - and Ů% of the required carrier material. The granularity of the carrier material obtained is evident from Table 1 below.

Example 2 ..

In the apparatus of Example 1, the same amount of carrier material (54 liters) was used, but the amount of water supplied was increased to 47 µl per hour and, as a consequence, the speed of the mixture.

rem up to 0.41 mm / sec. After about two materials and 82% of the required scrubber carrier is leaching inhomogeneous catalysts. The grain spectrum of the received carrier carrier particles is complete. The catalyst can be seen from the following

At this .feeding velocity toward .table .1.

; ru is lured у; рг'йпШг.и 28% washed up

TABLE.!'

• Coating - grain grain Unsorted carrier I iMo3fčz (example! ‘Carrier from example > 300.io- «m fl, R% 0,3 '% 0; 4%. -300—200 .. 10 · im im Д6% 2.8'P / o 2 (9 ¥ o Ж0-1B0 ..- J10-®: m : 6.0,6 '% i67; 0% 72.3% 100— 63. IQ ⁶ m .22,5% 24; o% ЖЗ'0 / о 63— 40.10 8.5% ; 5; D% D! -% <40.10- «m 5.6 P / o 0.3 o / o 0.0%

The palladium catalysts were prepared from the starting material used and the carrier obtained according to Examples 1 and 2 according to the invention described in DOS 2 240 4-6, and were used for the hydrogenation dehalogenation of dichloroacetic acid to acid.

TABLE 2 in the fluid phase fluidized bed monochloroacetate according to the method disclosed in DOS No. 2,053,115. The results obtained with three different catalysts are summarized in Table 2.

The palladium catalyst on the unsorted support of the support of Example 1 with the support of Example 2

0.7

0.11

1. Pd catalyst content (% by weight)

2. Maxlmál. catalyst content per m ³ of reactor space (kg / m ³ )

3. Pure nicochloroacetic acid received per m ³ of reactor space and hour (kg / m ³ .h)

4. Upward velocity of the crude monochloroacetic acid in the exclusion zone 2 (mm / s)

5. Speed in sorting by countercurrent carrier (mm / s) ·

The values summarized in the tables show that the amount of pure monochloroacetic acid obtained in the fluidized bed in the liquid phase can be per m ^{3 of} space, respectively. of reactor volume and in 1 hour, considerably increase if a larger proportion of fine particles is discharged in countercurrent sorting at a higher rate.

In general, according to the method of the invention, it is preferable to sort the support material for the catalyst upstream instead of downstream

0,7 0,7

55

123

0.19 0.35

However, of course, 0.3 to 0.41 may also treat the finished catalyst support in the same manner. The latter method only has the disadvantage that the leached inhomogeneous catalyst particles, which of course are more valuable than the corresponding carrier particles, are either lost or must be processed, for example, to palladium, which is by no means particularly economical.

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SUBJECT

Claims (3)

1. A process for the production of pulverulent silica catalyst catalysts or palladium catalysts and silicic acid catalysts for spray-fluidized fluidized-bed reactions in a liquid phase, characterized in that inhomogeneous particles of catalyst support or catalyst are washed away. in a liquid flowing upwards according to the principle of countercurrent sorting, wherein the speed of the liquid flowing upwards is at least as high as the rate of product withdrawal OF THE INVENTION from a sedimentation zone in carrying out catalytic reactions in a fluid phase liquid phase. 2. Process according to claim 1, characterized in that the catalyst support particles or catalyst particles have a diameter of 20.10 ^-6 m to 2.10-3 m. 3. The method of claim 1, wherein the upstream liquid is water.