DE1273495B - Process for the preparation of a silica catalyst containing phosphoric acid - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN - ^ W ^ PATENT OFFICE

EDITORIAL

Tnt. Cl .:

German class:

Number:
File number:
Registration date:
Display day:

BOIj

C07c

12 g -11/82
12 ο-1/01

P 12 73 495.1-41 (U 6576)

October 13, 1959

July 25, 1968

The invention relates to a process for the preparation of one suitable for the conversion of olefins Phosphoric acid catalyst as used for the alkylation of aromatic hydrocarbons, e.g. B. with alkyl halides or monoolefins, as well as for the polymerization of monoolefins which are gaseous in the normal state can be used. The manufacture of up to 90 percent by weight of phosphoric acid containing Silica catalysts from an intimate mixture of a pentavalent phosphorus-containing phosphoric acid with a solid silica material by heating to an elevated temperature and then Calcination at a temperature above 315 ° C is known per se.

However, there is a need for particularly high-quality and durable catalysts for these Art due to the increasing need for high-knock-resistant fuels for aircraft and automobiles Alkylation of aromatics with olefins or catalytic condensation of butenes and subsequent Hydrogenation to isooctanes. In addition, various polymers of olefins, especially propylene, required as an intermediate product in the manufacture of detergents or plastics.

However, the previously known and used solid phosphoric acid catalysts each have at least one significant disadvantage. They were made by mixing a silica material with a phosphoric acid in a weight ratio of P ₂ O ₆ to silica of about 2. Such a mixture is then converted into shaped particles and calcined at about 260 to 43o C ^0. The calcined catalyst then contains about 60 to 65 percent by weight P ₂ O ₅ . The catalysts so prepared are effective condensation catalysts and have a desirable external compressive strength (generally from about 4.5 to about 10 kg) when freshly prepared, but they have a tendency to decompose by softening or lose their activity during use fast. In order to maintain high activity of these catalysts, it is necessary to add small amounts of water vapor to the reacting charge in order to reduce moisture loss from the catalyst which degrades catalyst activity and to prevent the breakdown of heavy hydrocarbons to form tar. It is known that commercially available solid phosphoric acid catalysts have good activity when calcined at temperatures in the range of about 370 ° C., but their compressive strength decreases rapidly with use. In addition, although much higher calcination temperatures of z. B. 460 ⁰ C

Process for the production of a phosphoric acid
containing silica catalyst

Applicant:

Universal Oil Products Company,

Des Piaines, JIl. (V. St. A.)

Representative:

Dr. H.-H. Willrath, patent attorney,

6200 Wiesbaden, Hildastr. 18th

Named as inventor:

Mitchell Sebastian Bielawski,

Mount Prospect, JIL;

Julian Maris Mavity, Palatine, JIl. (V. St. A.)

Claimed priority:
V. St. v. America October 13, 1958
(766 673)

the compressive strengths to a certain extent, but at the same time they reduce the activity of the catalysts. Therefore, numerous methods have been described to improve the commercially available solid phosphoric acid catalysts by, for. B. a mixture of phosphoric acid and silica material at about 485 to 595 ⁰ C is calcined. It is previously also known to impregnate particles of silica material, which has been prepared by calcination at 650 to 1100 ° C or more with phosphoric acid and then calcined at preferably 300 to 400 ⁰ C. In this way, catalysts are obtained which have improved structural stability and approximately the same activity as the commercially available solid phosphoric acid catalysts. However, none of these modifications showed sufficient improvement to displace the solid phosphoric acid catalysts already in use on the market.

From the Canadian patent 560 670 a process for the preparation of olefin polymerisers is

809 587/552

catalysts known in the silica _{gel according to P 2} O ₅ , from 3.0 to 7.5 parts by weight per part by weight of 2 hours of heating to about 200 to 675 ⁵ C with silica material, this mixture mixed with a phosphoric acid, the mixture pulverized temperature in the range of heated 95-232 ⁰ C a time and at about 190 to 213 ° C dried and subse- until a semi-solid formable state is ßend calcined at about 315-539 ⁰ C. The 5 has reached, the still hot mixture through extruder-ready catalyst contains 50 to 90 percent by weight of dieren converted into shaped particles and finally phosphoric acid and a particle diameter of the shaped particles are calcined ^{at a temperature in the bed about 20 to 180 μ, ranging from 460 to 76O 0 C.} .

In contrast to this, according to the invention, the is essential for the method of the invention

Pill-shaped catalysts are obtained, such as an unusually high P ₂ O ₅ content, which is usually obtained in the known ones by extrusion. comparable catalysts less than 3.0 parts by weight.For this, however, it is necessary to have the mass in one part by weight of silica material, and to have the semi-solid, plastically deformable state and not heating the mixture until it is semi-powdered, so that the form-solid, malleable state in which the environment is possible in this way. Also, according to 15 mass can then be extruded directly, the Canadian patent 560 670 achievable. Preferably, according to the invention, the

Breaking strength not, there made sufficiently for a catalyst in such a manner that one is at 538 ^p C calcined catalyst according 500stündigem mixture of 25 to 10 weight percent silica-use in an olefin polymerization only 2.0 kg containing solids and 75 to 90 weight percent of a . 20 Polyphosphoric acid at 79 to 85 percent by weight

For the production of pill-orange catalysts from P ₂ O ₅ before shaping to about 170 to 180 ^q C phosphoric acid and silica is also heated in the. In addition, it is advantageous in the method of the USA. Patents 2,525,145 and 2,584,102 an invention in that the calcination of the addition of boric acid or B ₂ O ₃ or a post-catalyst moldings 0.5 to 2 hours at 530 until treatment of the calcined mass with a volatile 25 675 ⁰ C in an inert gas undertakes. Phosphorus halogen compound described. Here, too, the catalysts produced according to the invention

However, with are no catalysts from satisfactory catalysts are particularly suitable for the polymerization The constant abrasion resistance and compressive strength of unsaturated hydrocarbons and alkylation achieved. Despite a considerable amount of aromatics with a replaceable hydrogen atom Phosphorus oxychloride falls ζ. B. the compressive strength after 30 on the ring core with olefins or alkyl halides. about 2 hours of use on about the They are characterized by their high breaking strength, half value. because in practice it was found that the used

According to an older proposal, the catalyst is produced after 580 hours of use in the alkylation of phosphoric acid and silicophosphoric acid from benzene with ethylene-containing cracking waste gas-containing polymerization catalysts by means of a compressive strength of over 5 and mixing of powdered kieselguhr with phosphorus end des 2 hours of use in the propylene polyacid, shaping the mixture thus obtained with merization of the original compressive strength by exerting a high pressure until the mass showed no reduction in excess of 12.2, while the glass-like appearance has assumed, and calcium percent propylene conversion is highest with the kidneys of the shaped pieces. The pressure here must be more than 40 catalysts which ^{had been calcined at a temperature above at least 10 kg / cm 2} , preferably 15 kg / cm ² or 460 ° C., and the pressure treatment at higher temperatures is not necessary

Temperature cannot be carried out above 150 ° C. Rehydration with water vapor, which at This pressure treatment makes the manufacturing use of the known at about 400 to 500 or drive, however, cumbersome and expensive. 45 510 ° C calcined catalysts was required.

So while phosphoric acid catalysts are unlike other processes, neither is it

sufficient activity, sufficient resistance that the gaseous olefins are purified or concentrated against excessive hydrogenation and at the same time. Such olefin gases appear in improved mechanical durability, especially in lower concentrations, in various Rafin pill form compared to the solid phosphoric acid 50 finierungsgasströmmen, mostly diluted with non-commercial catalysts not according to the mentioned settable gases, such as hydrogen, nitrogen, methane, procedures from paste-like masses of ethane and Propane. A useful refinery off-gas is phosphoric acid and silica-like material, e.g. B. from a catalytic cracking plant contains e.g. B. diatomaceous earth can be prepared in accordance with 4.0% nitrogen, 0.2% carbon monoxide, 5.4% Wasserder invention it has been found that a catalyst manufactured fabric 55, 37.8 ° / ₀ methane, 10.3% Ethylene, 24.7% ethane, can be provided, which has all these advantageous properties of 6.4% propylene, 10.7% propane and 0.5% C ₄ "carbon properties, and the invention aims at the hydrogens; the total olefin content is only obtained from catalysts that are 16.7 mole percent in pill form.

unusually high activities and great mechanical The phosphoric acids used in the manufacture of the

Durability in use without using additional catalyst of the invention are measures such as. B. constant moistening of the z. B. orthophosphoric acid, pyrophosphoric acid, catalyst during operation, _{combine with each other (H 4} P ₂ O ₇ ), triphosphoric _{acid (H 8} P ₃ O ₁₀ ), tetraphosphorus, that is, their acid present after calcination (H ₆ P ₄ O ₁₃ ) and / or hexametaphosphoric acid. Composition during the condensation reaction, however, it is useful to keep phosphoric acids for a long time. 65 with a relatively high ratio of P ₂ O ₅ to

Such advantageous catalysts are bound water.

of the invention produced by having a one can, for. B. assume an acid that is about

Mixture with a phosphorus content, calculated as 75 to about 100% H ₃ PO ₄ or some free phosphorus

Contains pentoxide. As a result, it can contain a certain percentage of pyroic acid. Inside this Concentration range, the acids have different viscosities and can easily be mixed with the adsorption materials mix.

It has been found that pyrophosphoric acid can be combined with the silica material at temperatures somewhat above the melting point (61 ^° C.) and the heating time can differ somewhat from that which is used with ortho acid.

Triphosphoric acid can also be used for the preparation of catalysts according to the invention will.

Another phosphoric acid for the preparation of the catalyst according to the invention is tetraphosphoric acid, which corresponds to the double oxide of the formula 3 H ₂ O · 2 P ₂ O ₅ . However, it is not necessary to crystallize the tetraphosphoric acid prior to its use, rather the entire tetraphosphoric acid mixture can be combined directly with the silica material.

Polyphosphoric acid, such as is produced when orthophosphoric acid and / or pyrophosphoric acid is heated in a suitable device and whose P ₂ O ₆ content is about 79 to about 85 percent by weight, can also be used and has proven to be particularly useful. In a P ₂ O ₅ content of 79.5% containing 24.5 ° / ₀ orthophosphoric acid, 45.2% pyrophosphoric acid, 26.0% triphosphoric acid, and 4.3% of unidentified phosphoric acid, or with a P ₂ O ₅ -Content of 84 percent by weight, it consists of 57 percent by weight triphosphoric acid, 17 percent by weight hexametaphosphoric acid, 11% pyrophosphoric acid, 5 percent by weight orthophosphoric acid and 10 percent by weight unidentified phosphoric acids.

The silica-like solids used according to the invention are, for. B. diatomaceous earths, kieselguhr and artificially produced porous silica or diatomites, which are naturally occurring kieselguhrs, which have been ^{dried by heating at about 205 to 370 °} C. and contain about 90% silica. The remainder consists of metal oxides and a loss on ignition of about 3.7%. The second class of silica solids consists of aluminum silicates such as full earths and clays, e.g. B. bentonite, montmorillonite, acid-treated clay. Each adsorbent has its own specific influence on the effectiveness of the catalyst, which does not necessarily have to be identical to that of other representatives of this class.

In the preparation of the catalyst mixture according to the invention, polyphosphoric acid (84% P ₂ O _6), for example mixed at about 17O ⁰ C with diatomaceous earth from room temperature in a weight ratio of about 3.0 to 7.5. The mixture is slightly moist and becomes ^{plastic in a press at about 170 °} C. so that it can be cut into pieces. The particles are then calcined for about 0.25 to 8 hours, preferably about 0.5 to 2 hours.

The solid phosphoric acid catalyst of the invention is particularly useful for solid operation Suitable for bed. In the continuous process, the throughput speeds can be in the range of about 0.1 to 20 or more can be varied.

The catalyst bed and the reaction components can also be used in compact fluidized bed processes flow past one another in cocurrent or in countercurrent, or the catalyst can be in the form are brought into the reaction zone by calcined extrudates. When the alkylating agent or the polymerization charge is gaseous, the fluidized bed process can be used.

example 1

A solid phosphoric acid catalyst (Catalyst A) was prepared by stirring 43.2 g of diatomaceous earth in 160 g of polyphosphoric acid (83.5% P ₂ O _5), which was preheated before 20 minutes 170 ⁰ C. After mixing for 5 minutes, the mixture was ^{heated in an oven at about 170 °} C. for about 30 minutes. After the first 10 minutes the mass was stirred every 5 minutes. Before it was put into the oven, the mass was moist and plastic and remained practically unchanged in appearance and consistency for another 15 minutes. During the past 5 minutes, however, a hard mass, which was then removed from the oven and extruded by means of a hydraulic press at 17O ⁰ C was formed. The Preßstränge was cut into pills and 1 hour at 170 ⁰ C heated, whereafter they were calcined in a muffle furnace for 1 hour at 560 ⁰ C.

This catalyst was used for the alkylation of benzene with ethylene in the following way:

Benzene and a synthetic mixture of ethylene, ethane and methane were introduced into a closed reactor with 193 g of catalyst A. The reaction was carried out under a pressure of 63 atm. at an average rate of 0.75, a benzene-ethylene molar ratio of about 10, a temperature of 290 ^° C. and a water content of 0.26 mol percent, based on the total batch. The experiments were carried out in periods of 22, 22 and 48 hours. A spectrometric analysis of the dimensions of the batch and of the gas flowing out showed that the conversion of the ethylene was practically complete. All of the liquid products were fractionally distilled and the desired fractions subjected to infrared analysis, which showed that 85 to 88% of the reacted ethylene or 93 to 95% of the reacted benzene was present as ethylbenzene.

These results are illustrated in the following table,

Table I.

% converted ethylene
% converted ethylene, be
counts as ethylbenzene ...
Higher aromatics 99
85.1
14.9 99
88.1
11.9 97
87.9
12.1 total quantity
% converted benzene, be
counts as ethylbenzene ...
Higher aromatics 100.0
93.0
7.0 100.0
94.3
5.7 100.0
94.5
5.5 total quantity 100.0 100.0 100.0

Two further experiments were carried out under similar conditions, but at a temperature of 315 ^° C .; the results of these two separate experiments are illustrated in the table below.

1,273,495 8th 7th Table III Table II

% converted ethylene
%. converted ethylene, calculated
than ethylbenzene
Higher aromatics 98
85.6
14.4 98
86.1
13.9 total quantity
% converted benzene, calculated
than ethylbenzene
Higher aromatics 100.0
93.0
7.0 100.0
93.2
6.8 total quantity 100.0 100.0

% converted ethylene .. 5

% converted ethylene,
calculated as ethylbenzene

% converted benzene,
calculated as ethylbenzene

86.6

87.31

94.10

86.7

88.39

94.43

86.7

89.15

95.03

The catalyst was analyzed after a total run time of 123 hours, and it was found that the content of free P ₂ O ₅ was increased from 12.2% to 16.7%, while the content of titrierbaremP ₂ O ₅ is from 58 .0% to 56.9%.

To take advantage of the catalyst A to illustrate, was repeated the experiment using solid phosphoric acid catalyst (catalyst B), which is only about 75% of phosphoric acid containing ⁰ C and at a lower temperature, namely at 310 to 36O, was calcined, ie not in Is consistent with the invention. The benzene was introduced into the reactor which contained 185 grams of Catalyst B. The synthetic mixture of ethylene, ethane and methane was also introduced. The conditions were similar to the previous experiment, ie the pressure was 63 atm., The throughput rate 0.75, the benzene-ethylene molar ratio about 10.8, the moisture content, based on the entire batch, 0.26 mol percent and the temperature 290 ^° C. The duration of the experiment was 12, 24, 24 and 23 hours. The results of these tests are shown in the table below.

Example 2

In another experiment, the approach consisted of a synthetic mixture of ethylene, nitrogen, hydrogen and methane (ethylene content about 12 mole percent). The aromatic batch consisted of thiophene-free benzene, and in the first part of the experiment it contained about 0.4 percent by weight isopropyl alcohol, which was supposed to provide the water for the hydration of the catalyst. The test conditions were as follows: pressure about 65 atm., Temperature range from about 290 ° C at the beginning to about 315 ° C at the end, flow rate 0.57 and benzene-olefin molar ratio about 8. The catalyst was processed in the same way prepared as catalyst A, ie a mixture of about 80% polyphosphoric acid and 20% diatomaceous earth was prepared, which was then extruded and cut into particles, which were calcined ^{at 560 ° C. for 1 hour.} The results of a 580 hour long-term test with regard to activity, stability, product distribution and quality of the catalyst are shown in the table below.

Table IV

Catalyst age in hours:

Beginning of the orbital period

End of the orbit period

Mol percent water (entire batch) ...

Catalyst temperature ^{, 0 C}

% converted ethylene (average) ..

% converted propylene

% ethylene converted calculated as

Ethylbenzene

s-butylbenzene

Diethylbenzene

Residues calculated as diethylbenzenes

total quantity

% propylene converted calculated as

Cumene

«-Methylstyrene

total quantity

% benzene converted calculated as

toluene

Ethylbenzene

Cumene

α-methylstyrene

s-butylbenzene

Diethylbenzene

Residues

total quantity

125

290 77.4 100.0

81.5

14.1 4.4

100.0 100.0

100.0

0.2

84.8

5.4

7.3 2.3

248
268

0.25

100.0 100.0 317
82.6
100.0

100.0

372
388

317
85.5

100.0

468
484

318
90.0

484
580

0.006 318
90.0

91.2 0.7 3.1 5.0

100.0

0.1 95.3

The liquid mixture for the period from the 372nd to the 580th hour contained pure benzene without isopropyl alcohol. Prior to this period, the isopropyl alcohol was dehydrated to add 0.25 mole percent water deliver. The results show that the alkylation of the benzene batch is essentially dry Conditions, d. H. after 364 hours and at approximately 317 ° C, an improvement in the ethylene conversion as well as a substantial improvement in the effectiveness of the conversion of ethylene and benzene to ethylbenzene caused. During the last quarter of the attempt (between the 460th and 580th ^ hour) less than 10% of the ethylene converted and only 5% of the benzene converted into material implemented whose boiling point was above that of ethylbenzene.

The catalyst was removed after completion of the test from the reactor and exhibited a surface compressive strength of about 5.27 kg, a carbon content of less than l ° / ₀ and a free P ₂ O ₅ content, of from 12.4% to about 17 % had increased while there was apparently no loss of the total titratable amount of P ₂ O ₅ ; the fresh catalyst had a total titratable P ₂ O ₅ content of 58.30% and the used catalyst of 58.26%. (The total titratable amount of P ₂ O ₆ represents an easily determinable analytical value, which is very suitable for comparative _{experiments, but does not represent the real total P 2} O ₅ content, which can be determined by the more careful or more complicated gravimetric analysis .)

It can be seen that the particular catalyst which was used in the reaction and of a Mixture of 80% polyphosphoric acid was prepared before calcination and at relatively high levels Temperature of over 530 ° C was calcined, as an alkylation or condensation catalyst at relatively low temperatures and without additional moisture to maintain activity of the catalyst can be used.

Claims (3)

Patent claims: 1. A process for the preparation of a silica catalyst containing up to 90 percent by weight of phosphoric acid by mixing a pentavalent phosphoric acid containing phosphoric acid with a solid silica material, heating the mixture to an elevated temperature and subsequent calcination at a temperature above 315 ° C, characterized in that one Mixture with a phosphorus content, calculated as P ₂ O ₅ , of 3.0 to 7.5 parts by weight per part by weight of silica material, this mixture is heated to a temperature in the range from 95 to 232 ° C until it reaches a semi-solid, moldable state has converted the still hot mixture into shaped particles by extrusion and finally calcined the shaped particles at a temperature in the range from 460 to 760 ° C. 2. The method according to claim 1, characterized in that heating a mixture of 25 to 10 weight percent siliceous solids and 75 to 90 weight percent of polyphosphoric acid at 79 to 85 weight percent P ₂ O ₅ prior to deformation of about 170 to 18O ⁰ C. 3. The method according to claim 1 or 2, characterized in that the calcination of the Catalyst moldings for 0.5 to 2 hours at 530 to 675 ° C in an inert gas. Considered publications:
U.S. Patent Nos. 2,525,145, 2,584,102; Canadian Patent No. 560,670. 809 587/552 7.68 Bundesdruckerei Berlin