EP2252568A1

EP2252568A1 - Method for processing hydrocarbon compounds including nitrile or amine functions

Info

Publication number: EP2252568A1
Application number: EP09703449A
Authority: EP
Inventors: Philippe Marion; Amélie HYNAUX; Dorothée LAURENTI; Christophe Geantet
Original assignee: Centre National de la Recherche Scientifique CNRS; Rhodia Operations SAS
Current assignee: Centre National de la Recherche Scientifique CNRS; Rhodia Operations SAS
Priority date: 2008-01-18
Filing date: 2009-01-09
Publication date: 2010-11-24
Also published as: RU2482104C2; TW200948778A; KR20100103605A; CN101970386A; WO2009092634A1; RU2010134410A; FR2926546A1; US20110112202A1; SG188077A1; JP2011512327A

Abstract

The invention relates to a method for processing hydrocarbon compounds including at least one nitrile or amine function. The invention more particularly relates to a processing method that comprises converting, by hydrodenitrogenation, hydrocarbon compounds including at least one nitrile or amine function, such as methylglutaronitrile or orthotoluenediamine, into ammonia, hydrogen, carbon monoxide and hydrocarbon compounds, in particular into hydrocarbon compounds having a small carbon number such as methane or into ammonia.

Description

Process for the treatment of hydrocarbon compounds comprising nitrile or amine functions

The present invention relates to a process for treating hydrocarbon compounds comprising at least one nitrile or amine function.

It relates more particularly to a treatment method of converting the hydrocarbon compounds comprising at least one nitrile or amine function into ammonia, hydrogen, carbon monoxide and hydrocarbon compounds including hydrocarbon compounds comprising a small number of carbon.

Many industrial processes generate effluents containing hydrocarbon compounds comprising nitrile or amine functions. Such effluents can not be released into the environment without treatment. When the concentration of these compounds is low in the effluents generated, several treatment processes have been proposed such as incineration, biological treatments, nitrification or adsorption processes. However, when the concentration of compounds comprising amine or nitrile functions is high or if these nitrile or amine compounds are by-products not directly valued by an industrial process for the manufacture of chemicals, it is preferable for the economy of these products. processes and for the environment to recycle these compounds without transformation or after transformation into products directly usable in the process or in other processes.

By way of example, mention may be made, as an industrial process, of effluents containing a high concentration of compounds comprising at least one nitrile function or nitrile by-products, the process for the manufacture of adiponitrile by hydrocyanation of butadiene used. industrially since 1970.

Thus, the 2-pentenenitrile compound (2-PN) does not react with hydrogen cyanide to form a dinitrile and is recovered by distillation separation as a non-upgraded byproduct stream. Similarly, 2-methylglutaronitrile (MGN) formed in the second hydrocyanation stage [0005] This non-recoverable by-product is most often destroyed by incineration in boilers for the production of steam.

However, some of these may be recovered totally or partially by chemical conversion into new useful compounds. Thus, the most important by-product in quantity in the manufacture of adiponitrile, 2-methyl-glutaronithel (MGN) JI may be especially hydrogenated to produce a branched diamine 2-methyl-pentamethylene diamine (MPMD) used mainly as a monomer for the manufacture of polyamide or as a raw material for the synthesis of chemicals. Other valuations of the MGN have been described.

[0007] The other dinitrile or mononitrile by-products are essentially recovered by combustion to produce energy. However, since these compounds comprise nitrogen atoms, the combustion gases contain nitrogen oxides. Thus, it may be necessary to treat the flue gases in units of transformation and destruction of nitrogen oxides called DENOx.

Industrial processes for the synthesis of 2,4 and 2,6 toluenediamines (TDA) generates by-products which must be destroyed because they are of little interest, namely, the mixture of isomers of orthotoluenediamines.

The problem of treatment and recovery of non-upgraded byproducts in, in particular, the process of hydrocyanation of butadiene and the manufacturing process of toluenediamine is still not fully resolved and new solutions are constantly sought.

One of the aims of the present invention is to provide a process for treating these compounds does not have the disadvantages of combustion or incineration and to improve the overall economy of the process, especially by transforming them into compounds valued and advantageously recyclable.

For this purpose, the invention provides a process for the treatment of hydrocarbon compounds comprising at least one nitrile or amine function in value-added compounds, characterized in that it consists in treating said compounds in a hydrodenitrogenation or hydrogenation step. hydrotreatment reaction with hydrogen under an absolute pressure between 0.1 and 10 MPa, preferably 0.5 MPa to 3 MPa, at a temperature between 200 ⁰ C and 500 ⁰ C, preferably from 300 ° C to 400 ⁰ C and in the presence of a hydrodenitrogenation catalyst to convert these compounds into ammonia and hydrocarbon compounds.

Thus, the process of the invention makes it possible, for example, to treat all or part of the streams of non-upgraded compounds comprising nithyl or amine functions generated in the processes for the hydrocyanation of olefins, more particularly butadiene or in processes for the manufacture of toluene diamine for recovering the nitrogen atom in ammonia form and most of the carbon and hydrogen atoms in the form of hydrocarbon compounds comprising 1 to more carbon atoms. These hydrocarbon compounds can be recovered as such or fed in a steam reforming and optionally methanation stage to be converted into either carbon monoxide and hydrogen or methane, products which are particularly valuable as energy generators but also as raw materials for the synthesis of many compounds. Thus, and by way of example, hydrogen can be used in many productions of chemical compounds such as the hydrogenation of adiponitrile or dinitrotoluene, carbon monoxide can be used in the process of synthesis of phosgene and methane in the synthesis of hydrocyanic acid.

According to another characteristic of the invention, the hydrodenitrogenation catalyst comprises a metal element belonging to the group of noble metals consisting of platinum, palladium, rhodium, ruthenium or transition elements such as nickel.

Advantageously and preferably the catalyst is of the supported catalyst type in which the metallic catalytic element is supported on a material, preferably porous, such as alumina, silica, aluminosilicates, silica-aluminas, activated carbons, zirconia, titanium oxide, zeolites.

The preferred catalyst of the invention comprises platinum deposited on a support selected from the group comprising silica, zirconia, aluminosilicates, silica-aluminas, zeolites. The hydrodenitrogenation reaction is carried out in the presence of a heterogeneous catalyst which is either dispersed in suspension in the reactor or in the form of a fixed bed or fluidized bed through which the flow of nithyl compounds or amino is fed. The catalyst can also be deposited on a monolithic support such as, for example, a honeycomb-shaped support.

The present invention is not limited to these embodiments given solely by way of illustration.

The preferred hydrodenitrogenation catalysts of the invention include platinum catalysts on zirconia, platinum on aluminosilicate, platinum on silica-alumina, platinum on zeolite.

The conversion rate of the compounds to be treated involved is very high, close to or equal to 100%. The products recovered are ammonia and mainly hydrocarbon compounds. Thus, the treatment of methyl-2-glutaronitrile makes it possible to obtain as hydrocarbon compounds, for the most part, methyl-2-pentane. The hydrodenitrogenation of orthotoluene diamine mainly leads to the production of methylcyclohexane. Ammonia is separated and recovered in particular by distillation.

During this hydrotreatment, it may also occur thermal cracking hydrocarbon chains leading to the formation of hydrocarbon compounds without a nitrogen atom and / or hydrocarbon compounds comprising nitrogen atoms. The latter can be converted into hydrocarbon compounds by reaction with hydrogen, depending on the operating conditions used. Moreover, cyclic compounds containing nitrogen atoms can also be formed such as picoline or its derivatives and piperidines, in the case of the hydrotreatment of MGN. According to the invention,% HDN is the ratio expressed as a percentage of the number of moles of hydrocarbon compounds not comprising a nitrogen atom produced either by hydrotreatment or by thermal cracking with respect to the number of moles of compounds to be treated. .

According to a preferred feature of the invention, the hydrocarbon compounds produced by hydrodenitrogenation or hydrotreatment such as 2-methylpentane and thermal cracking products may be subjected to a steam reforming or steamreforming to partially oxidize these compounds carbon monoxide (CO) and hydrogen (H ₂ ). These two products can be recovered and recovered directly as a mixture or after purification and separation. In this embodiment, it is preferable to remove the traces of ammonia contained in the hydrocarbon compounds so as not to affect the performance of the steam reforming.

According to another embodiment of the invention, this mixture of carbon monoxide and hydrogen may be subjected to a methanation reaction leading to the formation of water and alkanes with a low carbon number such as the methane. This steam reforming / methanation treatment is widely used in the oil industry. Typical catalysts for these reactions include supported nickel catalysts. The operating temperature is between 400 and 700 ⁰ C for steam reforming and between 200 and 400 ⁰ C for methanation.

A general description of the processes of steam reforming and methanation is given in the book "Petrochemical processes" Edition TECHNIP Tome 1 1965 whose authors are A. CHAUVEL, G. LEFEBVRE and L. CASTEX.

The method of the invention is particularly applicable to the adiponitrile manufacturing process by hydrocyanation of butadiene in two stages. This process is described in many patents and a detailed description is available in the SRI REPORTS No. 31 suppl B entitled "H EXAM ETHYL N DIAMINE".

It also applies to the manufacturing process of toluene diamine described in many documents and in particular in the reports SRI No. 1 supplement B "Isocyanates".

Other advantages, details of the invention will emerge more clearly from the examples which will be given below by way of illustration only.

The tests described below were carried out with two hydrodenitrogenation catalysts:

Catalyst A: Pt deposited on zirconia (Pt / ZrO ₂ )

Catalyst B: Platinum deposited on a silica-alumina support comprising a weight percentage of silica equal to 10 called Pt / SiAl 10 Catalyst A was obtained using a zirconia support with a specific surface area of 83 m ² / g.

Catalyst B comprises a silica-alumina support with a specific surface area of 352 m ² / g marketed by Condéa under the trade name SIRAL10. This support contains 10% by weight of SiO 2.

These catalysts are prepared according to the procedure below.

The supports are impregnated with a hexachloroplatinic acid solution H ₂ PtCl.sub.2. They are left to mature for two hours at room temperature to allow the solution to penetrate the pores. The products are then dried overnight (> 12 h) at 110 ^° C. and then calcined under a stream of air at 500 ^° C. for 1 hour (air flow rate of 60 cm ³ min ^-1 , temperature rise ramp). of 2 ° C.min ^"1 ), in order to decompose the precursor complex into platinum oxide. They are then reduced under a stream of hydrogen for 6 hours at 310 ^° C. (hydrogen flow rate of 60 cm ³ min ^-1 , temperature ramp up to 1 ° C min ^-1 ) to obtain a platinum metal.

The physico-chemical characteristics of the catalysts PtVZrO ₂ and Pt / SiAM O are collated in Table I.

The dispersion and the size of the platinum particles were determined by chemisorption of hydrogen. The platinum assay was performed by plasma emission spectrometry.

Table I

In the following examples, the abbreviations used have the meanings indicated below:

> MP: 2-methylpentane

> Pic: picolines (β-picoline, 2-amino-3-picoline, 6-amino-3-picoline)

>% HDN: percentage of hydrocarbon products containing no hydrogen atoms relative to the number of moles of compounds to be treated. EXAMPLE 1 Hydrodenitrogenation of the MGN under an absolute pressure of 0.1 MPa with the catalyst A.

The hydrodenitrogenation reaction (HDN) of methylglutaronitrile was carried out at different temperatures and under an absolute pressure of 0.1 MPa with a hydrogen flow rate of 55 ml / min and fixed bed of catalyst A with a mass of 15 mg, according to the following procedure in a dynamic microreactor.

The reaction mixture comprises pure 2-methylglutaronithl and hydrogen. Hydrogen, the flow rate of which is regulated by a mass flow meter (0 - 200 ml / min), dabbles in a saturator filled with liquid MGN, then goes into a condenser whose temperature controls the partial pressure of the MGN to obtain a partial pressure in MGN equal to 1.33 kPa. The reactor is placed in a tubular furnace whose temperature is controlled by a platinum probe regulator. The reaction temperature is measured by means of a thermocouple located at the level of the catalytic bed.

In order to avoid the condensation of the reagent and reaction products, the temperature of the entire apparatus is constantly maintained at 180 ^° C. A trap is located at the outlet of the test for condensing the reaction products and the unconverted reagent. The gases then go to the vent.

The concentration and the number of moles of each compound present in the condensed medium are determined by gas chromatographic analysis. The different yields obtained are collated in Table II below:

Table II

EXAMPLE 2 Hydrodenitrogenation of the MGN under an absolute pressure of 0.1 MPa (partial pressure of MGN = 1.33 kPa) with the catalyst B. Example 1 is repeated except for the type of catalyst which is catalyst B.

The yields obtained are summarized in Table III below:

Table III

EXAMPLE 3 Hydrodenitrogenation of the MGN at an absolute pressure of 0.55 MPa (partial pressure of MGN = 1.33 kPa) on the catalyst B.

Example 1 is repeated using 50 mg of catalyst A under an absolute pressure of 0.55 MPa and a hydrogen flow rate of 4 ml / min. When the tests are carried out under pressure, the reaction mixture is injected after expansion at atmospheric pressure in a gas chromatograph via a six-way valve.

The yields obtained are summarized in Table IV below:

Table IV

EXAMPLE 4 Hydrodenitrogenation of MGN under an absolute pressure of 1 MPa and a partial pressure of MGN equal to 1.33 kPa with catalyst B. Example 1 is repeated except for the type of catalyst which is catalyst B.

The yields obtained are shown in Table V below.

Table V

These results show that the conversion of MGN to hydrocarbon compounds is low under a pressure of 0.1 MPa for a temperature between 250 ⁰ C <T <350 ⁰ C, demonstrating a low activity of the catalyst under these operating conditions.

Under a pressure of 1 MPa, the yield of the conversion of MGN to hydrocarbon compounds is higher and reaches a value of 100% for a temperature of 350 ° C.

Under a pressure of 0.55 MPa, it is also possible to obtain a yield of this conversion of MGN to 100% hydrocarbon compounds for a temperature of 300 ° C.

Example 5

The hydrodenitrogenation reaction of orthotoluene diamine (OTD) was carried out under an absolute pressure of 1 MPa in a device identical to that of Example 1 with a hydrogen flow rate of 20 ml / min. catalyst mass A of 50 mg.

The reaction mixture consists of hydrogen and a mixture obtained as a by-product in a toluene diamine (TDA) production plant essentially comprising 2,3-diaminotoluene and 3,4-diaminotoluene. Hydrogen, the flow rate of which is regulated by a mass flow meter (0 - 200 ml / min), is bubbled in a saturator filled with molten OTD, then goes into a condenser whose temperature controls the partial pressure of OTD). In the example under consideration, the absolute pressure is 1 MPa with an OTD partial pressure of 1.33 kPa, the conditioning temperature being 140 ^° C.

The reactor used under pressure of 1 MPa is made of stainless steel (inner diameter 10 mm, length 40 mm). It is placed in a tubular furnace whose temperature is controlled by a platinum probe regulator. The reaction temperature is measured by means of a thermocouple located at the level of the catalytic bed.

When the catalytic tests are carried out under pressure (1 MPa), a capillary is located at the outlet of the reactor. It allows to maintain in the apparatus a pressure upstream, which is a function of the flow rate used as well as the diameter and length of the capillary. After expansion at atmospheric pressure, the reaction mixture is injected into a gas chromatograph via a six-way valve.

In order to avoid the condensation of the reagent and the reaction products, the temperature of the entire apparatus is constantly heated to 180 ^° C. A trap is located at the outlet of the test for condensing the reaction products and the unconverted reagent. The gases then go to the vent.

The analysis of the reaction mixture is fully automated and performed online by gas chromatography (Hewlett Packard chromatograph equipped with a flame ionization detector, an HP 3396 II series integrator and a capillary column of DB1 type of dimensions 50 mx 0.32 mm x 5 μm).

The methylcyclohexane is obtained very predominantly at 300 ° C. At 350 ^° C., the significant presence of toluene and methylcyclohexane is noted.

Example 6: Vapororeforming hydrocarbon compounds produced such as methylpentane: A flow of 5 g / h of methylpentane is fed to a gas phase reactor in parallel with a water flow of 7.5 g / h. The reactor contains about 100 ml of nickel base catalyst supported on alumina (70% nickel). The temperature is maintained around 550 ⁰ C by external heating. The pressure is regulated at 23 bar. At the outlet, the gas is cooled and analyzed. The conversion of methylpentane is complete. Only CO, hydrogen and to a lesser extent CO2 are detected.

Claims

claims

1. Process for the treatment of hydrocarbon compounds comprising at least one nitrile (nitrogen) function consisting in converting them into ammonia and hydrocarbon compounds, characterized in that it consists in treating said compounds comprising at least one nitrile or amine function in a step of hydrodenitrogenation by reaction with hydrogen under an absolute hydrogen pressure of between 0.1 and 10 MPa, a temperature of between 200 ^° C. and 500 ^° C. in the presence of a hydrodenitrogenation catalyst for converting said compounds into ammonia and hydrocarbon compounds.

2. Method according to claim 1, characterized in that the hydrodenitrogenation catalyst is a metal element selected from the group consisting of platinum, palladium, rhodium, ruthenium and nickel.

3. Method according to claim 2, characterized in that the catalyst comprises a metal element supported on a support selected from the group comprising alumina, silica, aluminosilicates, silica-aluminas, activated carbons, zirconia, titanium oxide.

4. Method according to claim 3, characterized in that the catalyst comprises platinum deposited on a support selected from the group consisting of zirconia, silica, alumina, aluminosilicate, silica-alumina.

5. Method according to one of the preceding claims, characterized in that the absolute pressure of hydrogen is between 0.5 MPa and 3 MPa.

6. Method according to one of the preceding claims, characterized in that the temperature is between 300 ° C and 400 ⁰ C

7. Method according to one of the preceding claims, characterized in that the compounds are nitrile compounds selected from the group consisting of methylglutaronithle, ethylsuccinonitrile, 2-pentenenitrile, 2-methyl-2-butenenitrile or mixtures thereof, isomers of ortho TDA.

8. Method according to one of the preceding claims, characterized in that the hydrocarbon compounds recovered at the end of the step hydrodenitrogenation processes are processed in a steam reforming step to produce carbon monoxide and hydrogen

9. The method of claim 8, characterized in that carbon monoxide and hydrogen are treated in a methanation process to produce lower alkanes such as methane.

10. Process according to claim 8 or 9, characterized in that the steam reforming and methanation step is carried out in the presence of a nickel-based catalyst supported at a temperature of between 400 and

700 ⁰ C for steam reforming and between 200 and 400 ⁰ C for methanation.