DE1284627B - Process for the production of silver with a large surface - Google Patents

Description

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It has been found that silver with a large amount also decomposes and therefore causes puffiness at the surface obtained by wearing silver lactate. May be mentioned e.g. B. lactic acid hydrazide or if in the presence of other metal lactates, by an inorganic carbonate such as ammonium carbonate, thermal treatment decomposes. An enlargement of the pore space can continue

In the earlier patent 1211 607 it has already been achieved that the decomposition in

been beaten, making silver catalysts by soaking an evacuated room,

of porous support materials with silver lactate and The metals obtained according to the invention are suitable

subsequent thermal treatment to produce. especially as oxidation catalysts, e.g. B. for the

In contrast, the inventive oxidation of olefins, such as ethylene or propylene,

Process the thermal treatment of silver io to the corresponding olefin oxides or for the

Lactate in the absence of porous support materials. Dehydration of alcohols to the corresponding ones

The thermal decomposition of silver lactate can cause aldehydes.

can be done in a variety of ways. Said reactions proceed at tempera heated to silver lactate gradually to temperature doors between 200 and 300 ° Cab, ie, one has the doors over 100 ⁰ C, then begins the thin liquid 15 catalyst preheat to this temperature, to the melt slowly decompose. In doing so, a reaction is set in motion, which then gradually increases in viscosity exothermically and which continues with further progress. As the reaction temperature rises, the warming slowly becomes so great that the total decomposition gases that emerge in the reactions described can only partially leave the melt when the feedstock is burned to form carbon dioxide and gradually an upturn and water come to the fore. It is therefore caused by swelling of the resinous mass. particular interest, a catalyst to be used After slowly heating to about 18O ⁰ C the activity is so great that at low melt solidifies the decomposition, and it is capable of operating a temperatures.

gray-black, tuff-like mass obtained from It has now surprisingly been found that

metallic silver and the still decomposition 25 the oxidation catalysts produced according to the invention

Includes products included. If this is heated up during the production of ethylene oxide

Product in the presence of oxygen, ethylene and oxygen have a much lower value

about 250 ° C a strongly exothermic reaction, start-up and working temperature than that

in the course of which the mass under carbon dioxide - previously known ethylene oxide catalysts. These

Development changes into pure, white silver, the very lower temperature can be 100 ⁰ C lower

has good strength. The product obtained in this way can be used as with the previously known catalysts,

be broken down to the desired size. When using the inventively obtained

The decomposition of silver lactate can also be used in the ten metals as an oxidation catalyst for olefins,

Ways to be made that one can have a silver such as ethylene or propylene, the metal can be used for

Lactate melt on a polished stainless steel plate containing 35 such catalysts commonly used

to a high temperature, e.g. B. 500 ° C, heated sentences contain such. B. barium, magnesium,

was allowed to drip on. With a corresponding size of calcium or cerium, the additives preferably up to

Drops, e.g. B. 0.1 cm ³ , the drops float up to 10 percent by weight. Cause of the Leydenfrost phenomenon for so long

the hot surface until decomposition is complete. 40 Example If the plate is tilted accordingly, this can

The decomposed material is fed directly into a collecting container 500 g of a crystallized, water-containing silver will. In this manufacturing process lactates are placed on a drying tray on a small, extremely light, porous silver electric heating plate or a surface burner balls received. 45 slowly and evenly heated. At a temperature

If you bring the silver lactate to an unpolished door at around 110 ^° C, it becomes a stopping point at which the

or artificially roughened metal surface, e.g. B. water escapes from the melt, achieved. Thereon

by spraying and heating the metal surface, the temperature is increased by 3 ° C per minute

high temperatures, e.g. B. to 300 ⁰ C, then covers 180 ⁰ C. In the course of the temperature increase decomposes

the metal surface with a firmly adhering, rough 50 the melt with evolution of gas. The viscose

porous layer of catalytically active silver, whose fact is so large that the gas melts

Thickness z. B. can no longer leave due to the duration of the spraying process, but a driving effect

can be varied within wide limits. It can e.g. B. unfolded. Has just before the end point of decomposition

In this way, on the metal surfaces of silver, the melt turns into a foamy, dark-colored

from 0.1 to about 5.0 mm in thickness can be obtained. Transformed and solidified to a mass of resinous consistency

this way, surfaces of reactor tubes can, then suddenly. The pre-decomposition is thus ended.

Reactor internals etc. directly with catalytically active. Thereafter, heating is continued to a temperature of

Silver plated so that the surface as 230 ⁰ C or the surface of the mass with open

Catalyst works. Touched the flame and initiated the post-decomposition.

If not the production of a pure silver 60 Post-decomposition is exothermic and gradual

is intended, but the production of silver, ignition automatically. After cooling down, it will now

contains admixtures of other metals, the finished silver catalyst can be removed from the sheet and

one such metal lactates, such as. B. gold, platinum, broken down to suitable piece sizes. You get

Barium, magnesium, calcium or cerium lactates, 250 g of silver catalyst with a density of 4.

mix with the original silver lactate. 65 The catalyst obtained in this way was poured into a diphyl-

It is also possible to have the porosity of the reaction tube heated according to the invention of 1000 mm in length and

according to the silver obtained by filling 21 mm clear width. About this catalyst

Substances mixed with the silver lactate, which were then removed at a bath temperature of 160 ° C

3 4

200 l / h a gas mixture passed, the following The gas leaving the reaction chamber had the

Composition: Composition:

Ethylene 5.00 percent by volume Ethylene 2.28 percent by volume

Carbon dioxide 6.72 percent by volume Carbon dioxide 8.45 percent by volume

The remainder is oxygen and nitrogen. ⁵ ethylene oxide 1.77 percent by volume

The gas leaving the reactor had the remaining oxygen and nitrogen,

Composition: The yield of ethylene oxide was 71.5%

Ethylene 3.64 percent by volume Example 4

Carbon dioxide 7.60 percent by volume ¹⁰ ... .... . ". . _ .., _T

Ethylene oxide 0.96 percent by volume ⁵⁰ , ° §. water-containing, crystallized silver lactate

_, "Jyjp-r *" · are melted in a heatable drip funnel.

The remainder is oxygen and nitrogen. _{zen and at such a rate on dne on 5Q ()} o _C

The yield of ethylene oxide was 70.5%. Preheated, slightly inclined, polished metal channel from

... 15 about 1200 mm in length and 100 mm in width,

Example 2 that the immediate decomposition of the silver

500 g of a crystallized, water-containing silver lactate with formation of silver in the lower third

Lactates are finished on a drying tray on one of the gutter. The drops of about 0.1 cm ³

electric heating plate or a surface burner content are placed on the gutter from such a height

heated slowly and evenly. Dripped on at a tempe-

A temperature of around HO ⁰ C becomes a stopping point at which lactate shatters into many partial droplets. You get

the water from the melt escapes, observed. in this way 200 g of a catalyst with the

The temperature is then increased by a bulk density of 0.95 per minute.

3 ^° C. and operates in the temperature range from 160 to In a reactor tube 1000 mm long and 21 mm 175 ^° C. 50 g of lactic acid hydrazide are poured into the viscous 25 inner diameter, 280 g of this material are poured into a melt. As a result, the evolution of gas in and through the tube at a bath temperature of melt is increased many times over, and 180 ^° C. at 200 l / hour. A gas of the following composition is obtained after the final decomposition, which is passed through by touching:

of the solidified melt with an open flame, ethylene 4.90 percent by volume

a catalyst mass, the density of which is now between 30 carbon dioxide and 6.10 percent by volume

1.5 and 2.5 moves. The remainder is oxygen and nitrogen.

The catalyst thus obtained was in a diphyl- The gas leaving the reactor had the heated one Reaction tube of 1000 mm length and composition:

21 mm clear width filled. He was then at an _{Äth Jen 3 30} percent by volume

Bath temperature of 160 ° C with 200 l / h. of a gas 35 carbon dioxide 6.90 percent by volume

the following composition is applied: ethylene oxide 1.20 percent by volume

Ethylene 4.70 percent by volume, remainder oxygen and nitrogen.

Carbon dioxide 6.70 percent by volume The yield of ethylene oxide was 75%.

The remainder is oxygen and nitrogen. ₄₀

The gas leaving the reactor was as described in Example 5

Composition: A 1100 mm long stainless steel tube with a

Ethylene 3.11 percent by volume diameter of 30 mm, its outer surface

Carbon dioxide 7.64 percent by volume «" «f the sandblasting fan has been roughened, _W1 approx

Ethylene oxide 1.16 percent by volume «by electrical resistance heating (600 amps,

"" J, "3.5 volts) brought to a temperature of 300 ° C.

The remainder is oxygen and nitrogen. _{Then wifd with the heated} compressed air spray gun

The ethylene oxide yield was 73%. _{s0 long} molten, water-containing silver lactate,

containing 10% lactic acid hydrazide, sprayed on,

B e i s ρ i e 1 3 50 until the surface of the pipe is closed with a

an even layer of silver. the

500 g of a crystallized, water-containing silver- the thickness of the layer is determined by the length of the spraying time Lactates are variable in a nitrogen purge. In the present experiment it was 1.5 mm. electrically heated oven on a drying tray, like the outside so with catalytically active silver

described in Example 1, heated. The decomposition is terminated with the appropriate sealing when the mass in a jacket vessel outside at 200 l / hour after the pre-decomposition. has frozen. The mixture is allowed to cool in a nitrogen stream, and a gas mixture applied äthylenhaltigen, obtained 300 g of a gray-black, porous mass of silver, while it from a bath liquid of 200 ⁰ C which is broken down to suitable piece size inside. was flowed through.

As described in Example 1, a diphyl- 60 The gas mixture had the composition:

heated reaction tube filled with the catalyst, _{Äth len 500} percent by volume

over the 200 l / h at a temperature of 160 C. Carbon dioxide 6.20 percent by volume

a gas mixture with the following composition τ »α« < j ο ι <*

are conducted: the remainder is oxygen and nitrogen.

65 The gas leaving the reactor was as follows Ethylene 4.75 percent by volume Composition:

Carbon dioxide 6.85 percent by volume, ethylene 3.50 percent by volume

The remainder is oxygen and nitrogen. Carbon dioxide 7.04 percent by volume

Claims (4)

5 6 Ethylene oxide, 1.08 percent by volume, if necessary in the presence of other metal lactates, The remainder is oxygen and nitrogen. ^{without the} use of porous carrier material The yield of ethylene oxide was 72% · ^d " ^rC ψ. ^ F ^{wk ±} _{u A} - _n ., ,,. 2. The method according to claim I ₃ characterized 5 draws that the silver lactate propellant Claims: admixed. 3. Use of the first process obtained according to claim 1 for the production of silver with metals as oxidation catalysts. large surface due to decomposing thermal 4. Use of the obtained according to claim 1 Treatment of silver lactate, thereby ge io metals as oxidation catalysts for the manufacture indicates that the decomposition, formation of olefin oxides from olefins.