NL7902291A - Hydroxylamine salts prodn. by reducing nitrate or nitric oxide - using platinum and.or palladium catalyst with small particle size - Google Patents

Hydroxylamine salts prodn. by reducing nitrate or nitric oxide - using platinum and.or palladium catalyst with small particle size Download PDF

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Publication number
NL7902291A
NL7902291A NL7902291A NL7902291A NL7902291A NL 7902291 A NL7902291 A NL 7902291A NL 7902291 A NL7902291 A NL 7902291A NL 7902291 A NL7902291 A NL 7902291A NL 7902291 A NL7902291 A NL 7902291A
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Netherlands
Prior art keywords
catalyst
microns
particles
platinum
nitric oxide
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Application number
NL7902291A
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Dutch (nl)
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Stamicarbon
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Priority to NL7902291A priority Critical patent/NL7902291A/en
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Classifications

    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00Nitrogen; Compounds thereof
    • C01B21/082Compounds containing nitrogen and non-metals and optionally metals
    • C01B21/14Hydroxylamine; Salts thereof
    • C01B21/1409Preparation
    • C01B21/1418Preparation by catalytic reduction of nitrogen oxides or nitrates with hydrogen
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals

Abstract

Prodn. of NH2OH salts is carried out by reducing NO3- ions or NO with H2 in an acidic medium in the presence of a finely divided Pt- and/or Pd-contg. catalyst. Improve comprises using a catalyst in which >=90% of total noble metal content is present in particles of dia. 20 mu. Catalyst pref. comprises 0.1-20 (esp. 1-12) wt.% noble metal on an inert support (esp. active C or graphite). Catalyst can opt. be mixed with particles of metal-free support with a dia. of 20-100 mu. Pref >=60% of the total metal content of the catalyst particles is in particles of dia. 10 mu. NH2OH salts are used in mfr. of caprolactam from cyclohexanone. Catalysts have higher activity and selectivity than conventional catalysts.

Description

v f *

Stamicarbon BV 3074

Inventor: Cornells G.M. VAN DE MOESDIJK in Elsloo

METHOD FOR PREPARING A HYDROXYLAMINE SALT AND INCLUDING

USE CATALYST

The invention relates to a process for the preparation of a hydroxylamine salt by reducing nitrate ions or nitric oxide with hydrogen in an acid reaction medium in the presence of a finely divided platinum and / or palladium-containing catalyst.

Hydroxylamine salts are widely used today in the preparation of caprolactam from cyclohexanone. The review of these salts by reduction of nitric oxide is described, for example, in British Pat. Nos. 772,693 and 1,463,857 and U.S. Pat. No. 2,628,889. The preparation of these salts from nitrate ions is known, inter alia, from U.S. Pat. Nos. 2,827,362, 3,514,254 and 3,767,758.

Suitable noble metal catalysts with, for example, activated carbon or graphite as the carrier material, are commercially available for carrying out this known process. In order to increase the activity of these catalysts, known activators, such as, for example, GeO in the reduction of nitrate and SeO in the reduction

LA

of nitric oxide can be used.

It has now been found that the activity of the noble metal 20 can be further increased if one uses a supported noble metal catalyst in which at least 90% of the total amount of noble metal (platinum and / or palladium) is present in the catalyst particles of diameter below 20 microns. It has also been found that the selectivity of such a catalyst is also more favorable than that of the corresponding catalyst of the usual particle size.

The process according to the invention for the preparation of a hydroxylamine salt by reducing nitrate ions or nitric oxide with hydrogen in an acid reaction medium in the presence of a finely divided platinum and / or palladium-containing catalyst is characterized in that a catalyst is used in which at least 90% of the total amount of noble metal is present in the catalyst particles with a diameter below 20 microns.

790 2 2 5 1 O. - * -2-

The catalyst material for use in the process according to the invention can be obtained by starting from a carrier material with the desired amount of particles with a diameter below 20 microns in the known manner in the preparation of the catalyst. It is also possible to obtain the catalyst material in question by separating the desired quantity of precious metal-containing particles with a diameter of less than 20 microns from known catalyst material.

In the process according to the invention, a catalyst is preferably used in which at least 60% of the total amount of noble metal is present in the catalyst particles with a diameter below 10 microns.

In the practical implementation of the process according to the invention, it may occur that, in view of the fineness of the catalyst material, it is difficult to filter off the catalyst. By adding an amount of inert material, for example used carrier material, with a particle diameter larger than that of the catalyst material, for example 20-100 microns, a normal course of the filtration can be achieved without disadvantage for the activity and selectivity of the catalyst. An amount of 0.3-10 g of inert material is very suitable per gram of catalyst material.

Any inert support material with which the desired particle size of the catalyst material can be obtained can be used in the catalyst according to the invention. Activated carbon or graphite is very suitable as a carrier. The amount of noble metal in the catalyst according to the invention can be varied, for example between 0.1 and 20% by weight of the total catalyst material. Usually the catalyst of the invention contains 1-12% by weight of noble metal.

The invention is further illustrated in the following examples. Grain distribution of the catalysts in the Examples and Comparative Examples was determined in an aqueous medium using Nonidet P40 (trademark) as dispersant using a Retsch-35 ultrasonic bath and microsieves ranging in hole diameter from 10 to 100 micrometers in 5 micrometer increments.

790 22 9 1 -3- r

Example I

In a reactor with an effective volume of 1 liter, equipped with a turbine stirrer with a diameter of 4 cm, 750 milliliters of an aqueous solution containing 2.5 moles of sodium nitrate 5 and 2.2 moles of phosphoric acid per liter were used to adjust the pH of NaOH was adjusted to 1.5, 0.75 g of catalyst and 0.225 mg of GeO (activator) were added)

Subsequently, hydrogen was passed through the aqueous solution at a pressure of 100 kPa for 120 minutes at a temperature of 30 ° C and a stirring speed of 1500 revolutions per minute.

Palladium on activated carbon (10% by weight of palladium) with 100% particles smaller than 10 microns was used as the catalyst. A sample of the reaction mixture was taken every 30 minutes.

The analysis of the samples showed that the activity of the catalyst averaged 37 g hydroxylamine per g palladium per hour and the selectivity averaged 90%.

Comparative example 1

Example I was repeated using only another grain distribution of the catalyst. Of the catalyst, 95% of the particles were less than 85 microns, 50% less than 20 microns, and 30% less than 10 microns.

The activity was now 18 g hydroxylamine per g palladium per hour and the selectivity 80%.

Example II

Example I was repeated with 0.375 g of a palladium-platinum catalyst on activated charcoal as a support. The catalyst contained 8 wt% palladium and 2 wt% platinum. An amount of GeO was used as activator, the activity of the catalytic

a

sator was the highest (2.5 mg). 100% of the 30 particles of the catalyst were smaller than 15 microns.

The activity of the catalyst was 100 g hydroxylamine per gram of precious metal per hour and the selectivity 80%.

790 2 2 9 1 w '** * -4-

Repeating this experiment with an additional 5 g of activated carbon did not adversely affect the activity and selectivity of the catalyst.

Comparative Example 2 Example II was repeated with only a different grain distribution of the catalyst. It was: 99% less than 80 microns, 73% less than 20 microns, and 32% less than 10 microns.

The activity was now 40 g of hydroxylamine per g of noble metal per hour and the selectivity was 70%.

Example III

In a reactor like. described in Example I, 1 liter of phosphoric acid (35 wt%), 0.375 g platinum on charcoal catalyst (5 wt% platinum, particle size: 100% less than 10 microns) and, as an activator, 2.5 mg SeO. Hydrogen was then passed through for 30 minutes, followed by 120 minutes at a temperature of 30 DEG C. and a stirring speed of 1500 revolutions per hour and hydrogen-nitrogen monoxide-containing gas mixture at atmospheric pressure. 120 liters of the hydrogen-nitrogen monoxide-containing gas mixture were passed through per hour. The hydrogen: nitrogen monoxide ratio was adjusted so that in the effluent gas containing 10% by volume of inert gas (mainly nitrogen and NO) this ratio was 8: 1. Every 30 minutes, a sample of the reaction mixture was analyzed and the amount of nitrogen monoxide consumed was determined.

The activity of the catalyst was 450 g hydroxylamine per g platinum per hour and the selectivity 87%.

Comparative example 3

Example III was repeated with only another grain distribution of the catalyst. This was: 99% less than 100 microns, 75% less than 30 microns, and 45% less than 15 microns.

The activity in this case was 220 g of hydroxylamine per g of platinum per hour and the selectivity was 79%.

7 9 0 2 2 9 1 -5-

Example IV

In a reactor with an effective volume of 3 liters, equipped with a stirrer and connected to a filtration vessel with 4 sintered steel filter candles, a hydrogen pressure of 1000 kPa of continuous nitrate was used at a temperature of 60 ° C and 5 catalyst reduced to hydroxylamine. An hourly 17 kilograms of an aqueous solution was charged to the reactor, which contained 2 moles of phosphoric acid and 2.3 moles of ammonium nitrate per kilogram. The reactor contained 50 grams of palladium on activated carbon (10 wt% palladium) with 100% particles smaller than 20 microns. To facilitate filtration, 70 grams of activated carbon with a particle size between 20 and 100 microns was added to the reaction mixture. The stirring speed was 2000 revolutions per minute. 2.5 milligrams of GeO0 per gram of catalyst

a

used as an activator. The resulting reaction liquid was discharged through the filter cartridges. The solid that collected on the filter candles was returned to the reaction mixture every 10 minutes by short pressure pulses. The experiment was terminated after a period of 100 hours.

The activity of the catalyst was 80 g of hydroxylamine per gram of palladium per hour and the selectivity 88%.

Comparative example 4

Example IV was repeated with a different grain distribution of the catalyst, without addition of activated carbon and under otherwise equal conditions. Of the catalyst, 100% of the 25 particles were less than 100 microns, 53% less than 20 microns, and 31% less than 10 microns.

The activity was now 40 g hydroxylamine per g Palladium per hour and the selectivity 85%.

7902291

Claims (9)

1. Process for the preparation of a hydroxylaraine salt by reducing nitrate ions or nitric oxide with hydrogen in an acid reaction medium in the presence of a finely divided platinum and / or palladium-containing catalyst, characterized in that a catalyst is used in which at least 90 % of the total amount of noble metal is present in the catalyst particles with a diameter below 20 microns.
2. Process according to claim 1, characterized in that a catalyst is used in which at least 60% of the total amount of precious metal is present in the catalyst particles with a diameter below 10 microns.
3. Process according to any one of claims 1-2, characterized in that, in addition to the support material in the catalyst, an amount of support material as such with a particle diameter of 20-100 microns is used.
4. Process according to any one of claims 1-3, characterized in that active carbon is used as the carrier material.
A method according to claim 1, as substantially described and further elucidated in the examples.
Hydroxylamine salt obtained using the method according to any one of the preceding claims.
Finely divided platinum and / or palladium-containing supported catalyst, suitable for use in the process according to any one of claims 1 to 5, characterized in that at least 90% of the total amount of noble metal is present in the catalyst particles with a diameter below 20 microns.
Catalyst according to claim 7, characterized in that at least 60% of the total amount of precious metal is present in the catalyst particles with a diameter below 10 microns.
Catalyst according to claim 7, as substantially described and further elucidated in the examples. 7902291
NL7902291A 1979-03-23 1979-03-23 Hydroxylamine salts prodn. by reducing nitrate or nitric oxide - using platinum and.or palladium catalyst with small particle size NL7902291A (en)

Priority Applications (2)

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NL7902291A NL7902291A (en) 1979-03-23 1979-03-23 Hydroxylamine salts prodn. by reducing nitrate or nitric oxide - using platinum and.or palladium catalyst with small particle size
NL7902291 1979-03-23

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0071097A1 (en) * 1981-07-31 1983-02-09 BASF Aktiengesellschaft Process for the preparation of hydroxylammonium salts
US5120699A (en) * 1990-07-18 1992-06-09 Basf Aktiengesellschaft Platinum-on-graphite catalysts and the use thereof
US5155081A (en) * 1990-07-18 1992-10-13 Basf Aktiengesellschaft Platinum-on-graphite catalysts
EP0577213A1 (en) * 1992-07-02 1994-01-05 Dsm N.V. Process for the preparation and purification of a hydroxylammonium salt solution
EP0773189A1 (en) * 1995-11-10 1997-05-14 Dsm N.V. Process for the preparation of hydroxylammonium salts
US6221328B1 (en) 1996-10-28 2001-04-24 Dsm N.V. Process for preparing hydroxylammonium salts

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0071097A1 (en) * 1981-07-31 1983-02-09 BASF Aktiengesellschaft Process for the preparation of hydroxylammonium salts
US4457906A (en) * 1981-07-31 1984-07-03 Basf Aktiengesellschaft Preparation of hydroxylammonium salts
US5120699A (en) * 1990-07-18 1992-06-09 Basf Aktiengesellschaft Platinum-on-graphite catalysts and the use thereof
US5155081A (en) * 1990-07-18 1992-10-13 Basf Aktiengesellschaft Platinum-on-graphite catalysts
EP0577213A1 (en) * 1992-07-02 1994-01-05 Dsm N.V. Process for the preparation and purification of a hydroxylammonium salt solution
EP0773189A1 (en) * 1995-11-10 1997-05-14 Dsm N.V. Process for the preparation of hydroxylammonium salts
BE1009767A3 (en) * 1995-11-10 1997-08-05 Dsm Nv Process for the preparation of hydroxylammonium.
US5792439A (en) * 1995-11-10 1998-08-11 Dsm N.V. Process for the preparation of hydroxylammonium salts
US6221328B1 (en) 1996-10-28 2001-04-24 Dsm N.V. Process for preparing hydroxylammonium salts

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