Isoamylenes dehydration catalyst

FIELD: hydrogenation-dehydrogenation catalysts.

SUBSTANCE: invention relates to catalysts used in isoamylenes-into-isoprene dehydrogenation process and contains, wt %: iron oxide 62-75.4, potassium carbonate 12-21.5, chromium oxide 1-3, potassium hydroxide 0.5-2.5, sulfur 0.1-2.0, ammonium nitrate 0.1-2.0, silicon dioxide 1-5, calcium carbonate 1-5, and cerium nitrate 1-3.

EFFECT: increased mechanical strength, resistance to saturated steam and moisture, and stability during long-time operation.

3 ex

 

The invention relates to catalysts for the dehydrogenation of olefinic hydrocarbons, in particular to catalysts for dehydrogenation of isoamylenes in isoprene, which is a monomer for the production of synthetic rubber.

Known catalyst for dehydrogenation of olefinic and alkylaromatic hydrocarbons containing iron oxide, chromium oxide, potassium carbonate, potassium silicate and zirconium dioxide (A.S. USSR № 426412, IPC601 J 23/86, publ. 10.01.96).

Closest to the present invention is a catalyst for dehydrogenation of isoamylenes in isoprene (RF patent No. 2127633, IPC601 J 37/04, 23/86, publ. 20.03.99). The catalyst contains iron oxide, potassium carbonate, potassium hydroxide, chromium oxide, zirconium dioxide and potassium silicate.

As the experience of commercial operation of the dehydrogenation catalysts of isoamylenes in isoprene, their life depends on their mechanical strength. Very high strength catalysts produce acceptable outputs only at higher process temperatures, i.e. energy-consuming. The main disadvantage of the known catalysts for the dehydrogenation of isoamylene in isoprene is their low mechanical strength due to the use as a binder material of potassium silicate. During operation at temperatures of about 600° in vapor environment, binder m is a material predetermined destroyed, that leads to a significant change in the mechanical strength of the catalyst (grinding) and, as a consequence, the pressure in the reactor. Requires frequent regeneration of the catalyst. The longer catalyst life is 10,000 hours, and then its replacement is necessary.

The objective of the invention is to provide a catalyst for dehydrogenation of isoamylenes in isoprene having a high mechanical strength, resistant to saturated steam and water at high temperature, stable quality during long-term operation.

The problem is solved by the development of a catalyst for the dehydrogenation of isoamylene in isoprene containing iron oxide (Fe2About3), potassium carbonate (K2CO3), chromium oxide (CR2About3), potassium hydroxide (KOH), sulfur (S), nitrite ammonium (MN4NO2), silicon dioxide (SiO2), calcium carbonate (caso3) and cerium nitrate CE(NO3)3·6N2O in the following ratio of components, wt.%:

iron oxide 62-75,4

potassium carbonate 12-21,5

the chromium oxide 1-3

the potassium hydroxide 0,5-2,5

sulfur 0,1-2,0

nitrite ammonium 0,1-2,0

silicon dioxide 1-5

calcium carbonate 1-5

nitrate of cerium 1-3

The difference of the invention from the closest is that the catalyst composition additionally with Elitsa sulfur, which is an activator of crystallization and inhibitor of coke formation in the process of dehydrogenation of isoamylenes, nitrite ammonium as a blowing agent, silicon dioxide, calcium carbonate and nitrate of cerium.

In the catalyst composition may contain fine technical sulfur obtained as a waste product in the desulfurization medium oil distillates.

When comparing essential features of the invention with those of the prototype revealed that they are new and are not described in the prototype, so we can make conclusion on the conformity of the proposed technical solution the criterion of “novelty”.

The introduction of new distinctive characteristics in combination with the achieved result indicates an inventive step of the proposed invention.

The present invention meets the criterion of “industrial applicability”because it can be used in industry, as evidenced by examples of specific embodiment of the invention.

Example 1

Catalyst for dehydrogenation of isoamylenes obtained as follows.

In a reactor with a stirrer and heated water is supplied and fall asleep calculated amount of potassium carbonate (K2CO3). The dissolution of potassium carbonate is carried out at a temperature of 70-90° With constant stirring for 30 minutes. Yes is the temperature in the reactor was raised to 100° With and fall asleep in it calculated the amount of iron oxide (Fe2About3). The resulting mass was incubated for 7 hours, then poured into the reactor calculated amount of chromium oxide (CR2O3), after an hour in the reactor fall asleep estimated number of cerium nitrate (CE(NO3)3·6N2O) and calcium carbonate (caso3). The resulting mass is kept in the reactor for 1 hour with constant stirring.

Then the resulting mass is unloaded from the reactor and fed into the mixer privately, where she pariveda to the consistency required for extrusion. Before the end of the evaporation in the mixer privately serves potassium liquid glass, components of which are silicon dioxide (SiO2) and potassium hydroxide (KOH), sulfur (S) and nitrite ammonium (NH4NO2). From faucets-privately the resulting mass is fed to the extrusion, and then the extrudate is dried, calcined, gradually increasing the temperature to 650° and maintaining at this temperature for 8 hours. The catalyst is cooled, activate nitrogen and blow hot air.

The finished catalyst has a mechanical strength 1,67 kg/mm2(the area of the granules was determined by its diameter); the catalyst is not destroyed when tested for 15 minutes in boiling water.

The process degidi the Finance of isoamylenes carried out on a laboratory scale continuous flow at a temperature of 600° With the dilution of the raw water vapor in a molar ratio of 1:20 and a feed rate of the hydrocarbon 1,0 h-1in a stationary catalyst bed containing the following components, wt.%: Fe2About3- 62,0;2CO3- 21,5; CR2About2- 3,0; CON - 0,5; S - 2,0; NH4NO2- 2,0; SiO2to 1.0; caso3- 5,0; CE(NO3)3·6N2O - 3,0.

Contact analyze gas chromatographic method for obtaining converged results.

The yield of isoprene on missed and reacted isoamylene is, accordingly, 36,6 and 84,0 % wt.

When tested in a laboratory setup for 200 hours of continuous operation the yield of isoprene on missed and reacted isoamylene has not changed.

Example 2

The catalyst was prepared as described in example 1. The catalyst has a mechanical strength of 1.25 kg/mm2; not destroyed when tested for 15 minutes in boiling water.

The process of dehydrogenation of isoamylenes carried out as described in example 1 using the catalyst containing the following components, wt.%: Fe2About3- 75,4;2CO3to 12.0; CR2About2-1,0; CON - 2,5; S - 1,0; NH4NO2- 0,1; SiO2- 5,0; caso3- 2,0; CE(NO3)3·6N2O to 1.0.

The yield of isoprene on missed and reacted Itami is received is accordingly, 36,8 and 82,0 % wt.

When tested in a laboratory setup for 200 hours of continuous operation the yield of isoprene on missed and reacted isoamylene has not changed.

Example 3

The catalyst was prepared as described in example 1.

The catalyst has a mechanical strength of 1.15 kg/mm2; not destroyed when tested for 15 minutes in boiling water.

The process of dehydrogenation of isoamylenes carried out as described in example 1 using the catalyst containing the following components, wt.%: Fe2About3- 68,0;2CO3- 18,9; CR2About2- 2,0; CON - 0,5; S - 0,4; NH4NO2- 1,5; SiO2- 2,2; caso3- 4,0; CE(NO3)3·6N2O - 2,5.

The yield of isoprene on missed and reacted isoamylene is, accordingly, 37,3 and 87.1 % of the mass.

When tested in a laboratory setup for 200 hours of continuous operation the yield of isoprene on missed and reacted isoamylene has not changed.

As seen from the above examples, the introduction of the catalyst sulfur, ammonium nitrite, silicon dioxide, calcium carbonate and nitrate of cerium gives the opportunity to obtain a catalyst with high mechanical strength, resistant to saturated steam and moisture, as determined by test in boiling water for 15 min, leads to increase the human life of the catalyst with high activity and selectivity when working in high temperatures.

Catalyst for dehydrogenation of isoamylenes in isoprene containing iron oxide, potassium carbonate, chromium oxide and potassium hydroxide, characterized in that it further contains sulfur, nitrite, ammonium, silica, calcium carbonate and nitrate of cerium in the following ratio, wt.%:

Iron oxide 62÷75,4

Potassium carbonate 12÷21,5

The chromium oxide 1÷3

The potassium hydroxide is 0.5÷2,5

Sulfur 0,1÷2,0

Nitrite ammonium 0,1÷2,0

Silicon dioxide 1÷5

Calcium carbonate 1÷5

Nitrate of cerium 1÷3



 

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SUBSTANCE: invention relates to production of isoprene for use in synthesis of isoprene rubber and butyl rubber used in tire industry and manufacture of general mechanical rubber goods. In the method of invention, isoprene is obtained by decomposition of 4,4-dimethyl-1,3-dioxan on calcium phosphate catalyst comprising synthesis of 4,4-dimethyl-1,3-dioxan by interaction of isobutylene-containing C4 fraction with aqueous formaldehyde solution in presence of acid catalyst to form reaction medium composed of oil and water layers followed by separation of oil layer into unreacted C4-hydrocarbons and 4,4-dimethyl-1,3-dioxan by rectification leaving bottom residue containing dioxan alcohols (high-boiling dioxan alcohols to be processed into additional product), separation of water layer, condensation of contact gas, and recovery of desired isoprene. Low-boiling part of hydrocarbons distilled off in processing of bottom residue of 4,4-dimethyl-1,3-dioxan rectification is separated and thus obtained lower product is discharged as a mixture of high-boiling dioxan alcohols, which constitute additional desired product, whereas upper product is combined with formaldehyde-containing blend fed into 4,4-dimethyl-1,3-dioxan synthesis zone. Acid catalyst utilized in synthesis of 4,4-dimethyl-1,3-dioxan is mixture of oxalic and phosphoric acids at weight ratio between 2:1 and 1:1, whereas summary concentration of acids in formaldehyde-containing blend is maintained between 1.5 and 2.5 wt %. Remaining high-boiling fraction of hydrocarbons taken off in processing of bottom residue of 4,4-dimethyl-1,3-dioxan rectification, which are mixture of heavy residue and high-boiling alcohols, are taken off in the form of by-product.

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1 dwg, 3 ex

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FIELD: hydrogenation-dehydrogenation catalysts.

SUBSTANCE: invention relates to catalysts used in isoamylenes-into-isoprene dehydrogenation process and contains, wt %: iron oxide 62-75.4, potassium carbonate 12-21.5, chromium oxide 1-3, potassium hydroxide 0.5-2.5, sulfur 0.1-2.0, ammonium nitrate 0.1-2.0, silicon dioxide 1-5, calcium carbonate 1-5, and cerium nitrate 1-3.

EFFECT: increased mechanical strength, resistance to saturated steam and moisture, and stability during long-time operation.

3 ex

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