Catalyst for the synthesis of halocarbons

 

(57) Abstract:

The invention relates to the production of catalysts for the synthesis of organofluorine compounds (penthaleidae General formula C2HClxF5-xwhere x varies from 0 to 4), in particular, to obtain trichotillomania, tetrafluorochloroethane and Pentafluoroethane (freon 123, 124 and 125, respectively). Describes a catalyst for the synthesis of halocarbons containing compounds of chromium (III), iron (III) and, optionally, zinc (II) and carrier - magnesium fluoride in the following ratio of components in terms of metals, wt.%: iron (III) 0,1-2,0, zinc (II) 0-2,0, chromium (III) of 6.5 to 12.0, magnesium fluoride rest. The technical result is an increase in conversion of perchloroethylene to 87-91%. 6 table.

The invention relates to the production of catalysts for the synthesis of organofluorine compounds (penthaleidae General formula C2HClxF5-xwhere x varies from 0 to 4), in particular to obtain trichotillomania, tetrafluorochloroethane and Pentafluoroethane (freon 123, 124 and 125, respectively), which are widely used as foaming agents, propellants and refrigerants.

The main method of synthesis of freon 123, 124 and 125 is Gazavat is escow constitute the catalytic composition.

Known formulations of the catalysts based on zinc fluoride on partially fluorinated aluminum oxide (international application WO 92/16479, publ. 01.10.1992). The catalyst is a fluoride zinc deposited on or aluminum oxide, pre-fluorinated to the ratio F: Al<2,7: 1; content of metallic zinc in the catalyst is from 1 to 10 wt%. The catalyst may additionally include other metals from groups V||| V||B, V|B, |||B ||B and |B of the Periodic table of elements with atomic numbers from 51 to 71.

When gidroftorirovaniya of perchloroethylene in the catalyst containing 2% Zn (optimal value) obtained high rates of conversion of the feedstock (90,5%) and selectivity for the amount of freon 123, 124, 125 (97,5%); selectivity for HFC 125 is only 11%.

However, catalysts based on alumina though, and have a high activity in the process of hydroperiodide of perchlorethylene, but represent significant difficulties when carrying out the process of the catalyst (or, previously, aluminum oxide) hydrogen fluoride due to mnogostadiinost and a large exothermic effect.

Known catalysts obtained on the basis of chromium oxide (III). So, in Roma (III). Moreover, the catalyst CR2O3obtained by the pyrolysis of (NH4)2Cr2O7having a high specific surface, subjected to preliminary treatment with one agent selected from CO, N2N2O or mixtures thereof.

Pre-treatment of the catalyst with hydrogen is that the catalyst loaded in the reactor was dried in a stream of nitrogen at a temperature of 400oWith about 8 h, then cooled to 175oS, after which the catalyst was treated at the same temperature with hydrogen for 1 h, the Flow of hydrogen was stopped. The catalyst after pretreatment was subjected to activation in a stream of nitrogen and hydrogen fluoride. The activated catalyst used in the process of synthesis of HFC 125. A mixture of hydrogen fluoride and HFC 124 in a molar ratio of 2: 1 was passed over the catalyst. The reaction temperature was changed from 275 to 400oC. the Yield of HFC 125 amounted to 67%.

Catalysts based on chromium oxide cause difficulties because of the need to handle them before synthesis of halocarbons hydrogen fluoride, accompanied by a high azotemia, and the allocation of water in the presence of gaseous hydrogen fluoride promotes high corrosion activedropdownlist halon 123 or HFC 124 used chromium (III), deposited on activated carbon in the form of oxide or hydroxide, halide or oxychloride, nitrate or sulfate. The content of chromium (III) in the catalyst is 3-50 wt.%, mostly from 1 to 20 wt.%.

So, when gidroftorirovaniya halon 123 at a temperature of 340oWith a molar ratio of HF:HFC 123=3,3:1, contact time of 9.9 with the conversion of halon 123 amounted to 83.5% and the selectivity to HFC 125 - 72%.

However, the catalysts, which is used as a carrier of activated carbon, are not subject to regeneration air, and the use of solvents for the recovery of catalyst activity is problematic. Therefore, the service life of such catalysts is significantly restricted.

For the synthesis of chlorofluorocarbons used chromogenicity a catalyst comprising a fluoride of chromium (III), evenly distributed on the magnesium fluoride.

Thus, according to the patent of the Russian Federation 2005539, B 01 J 37/03, publ. 15.01.94, taken as a prototype, the catalyst synthesis of chlorofluorocarbons prepare a mixture of magnesium fluoride with a solution of chromium chloride density of 1.35-1.38 in g/cm3. Before use in the process of synthesis of halocarbons catalyst is treated fluoride hydrogen at oral magnesium. However, in this method it is possible to produce a catalyst with a content of chromium (III) not more than 6.5 wt.% because of the limited solubility of chromium chloride in water.

Application khrommagnievogo catalyst manufactured according to the prototype and containing in its composition between 5.5 and 6.5 wt.% chromium (III), in the process of hydroperiodide of perchloroethylene to freon 123, 124, 125 gives the results presented in table. 1.

From the data table. 1 shows that the average conversion of perchloroethylene is 52,7% with a selectivity for the amount of freon 123, 124, 125 - 91,8%.

As follows from the above data, the main active component of catalysts for the synthesis of halocarbons is chromium (III), applied to the media, in the form of various compounds, oxide, hydroxide, halide, oxychloride etc.

The present invention is to increase the conversion of the original products while maintaining (or improving) the selectivity of the process for the amount of freon 123, 124, 125.

This problem is solved due to the increase in chromagnitude catalyst content(in terms of metal) chromium (III) from about 6.5 wt.% to 12.0 wt. % and the introduction of promoters - compounds of iron (III) from 0.1 wt.% up to 2 wt. % and not tied, hydroxide or oxohydroxide chromium, iron compounds - its chloride or nitrate, as compounds of zinc is its chloride, hydroxide or nitrate.

The increase in the content of chromium (III) catalyst 6.5 wt.% to 12.0 wt. % led while maintaining selectivity to increase the conversion of perchloroethylene to 18-19%, the maximum is achieved when the content of chromium (III) equal to 9 wt.% (PL.2).

The introduction of iron compounds (III) in the catalyst as a promoter in an amount up to 2 wt.% (in terms of metal) leads to an increase in the conversion of perchloroethylene from 71.6 per cent to 87-91% while reducing selectivity from 92.1% down to 78% (table. 3). Introduction zinc (II) in an amount of from 0.1 wt.% up to 2.0 wt.% in chromogenicity catalyst increases the conversion of perchloroethylene [but to a lesser extent than the introduction of iron (III)] from 71.6 per cent to 72.6-73,3% while maintaining selectivity at the level of 93% (table.4).

Data on the impact of joint presence in chromagnitude catalyst Zn (II) and Fe (III) are given in table 5. As can be seen, when the joint presence of the catalyst Fe (III) and Zn (II) able to increase the conversion of perchloroethylene to 74-80% (see tab. 5, columns 1 and 3), with selectivity for the amount of freon 123, 124, 125, equal to 92%.

SPO is tight 19,0 kg basic magnesium carbonate, was added to 57.0 l of distilled water and 19.9 kg of hydrofluoric acid (40% HF). A suspension of precipitated magnesium fluoride was dried at 100-300oC to a residual moisture content of 5 wt.%.

The solution mixture of the chlorides of chromium and iron was prepared in a reactor with a stirrer. The reactor was loaded 4,48 kg rl36N2O, 1,30 kg Fl36N2Oh and 1,94 l of distilled water. The solution was stirred at a temperature of 60oC for 1 h and cooled to room temperature.

The kneading of the paste were carried out in the mixer with Z-shaped blades. In the mixer was loaded 13,0 kg of powder of magnesium fluoride and the prepared solution of a mixture of chlorides of chromium and iron. The components were mixed until a homogeneous plastic mass.

Forming paste was performed by extrusion through a die plate with a diameter of 8 mm, the Obtained pellets were dried at 90oC for 24 h at 140oC for 5 h

The finished catalyst contained (in terms of metal) of 6.5 wt.% Cr (III) and 2.0 wt.% Fe (III), (magnesium fluoride - rest.

The catalyst was tested at a pilot plant in the process of gas-phase hydroperiodide of perchloroethylene. The reactor was loaded 0,22 l catalyst was applied nitrogen with a flow rate of 0.37 m3/h, raised tempera kg/h and has raised the temperature up to 450oC. the Flow of nitrogen was shut off and kept the catalyst in a stream of hydrogen fluoride for 0.5 hours the Reactor was cooled in a stream of hydrogen fluoride to 375oWith, set the flow rate of hydrogen fluoride, equal to 98.5 g/h, and gave perchlorethylene in the amount of 64 g/h (the molar ratio of HF:C2Cl4=8,0:1), creating excess pressure in the reactor equal to 0.3 MPa. Under these conditions the conversion of perchloroethylene was 84,1% and the selectivity for the amount of freon 123, 124, 125 - 84,9% (see tab. 6, column 1).

Example 2.

The ferric chloride solution was prepared in a reactor with a stirrer. The reactor was loaded 0.066 kg Fl36N2O and 1,72 l of distilled water. The solution was stirred for 1 h

In the mixer was loaded 13,0 kg of powder of magnesium fluoride obtained in example 1, then rl36N2About the number of 6.25 kg and mixed them for 15 minutes In the mixer was loaded a solution of ferric chloride. Mixing, molding paste and drying the granules of the catalyst was carried out according to example 1.

The finished catalyst contained (in terms of metal) to 9.0 wt.% Cr (III) and 0.1 wt.% Fe (III), magnesium fluoride - rest.

Activation and testing of the catalyst was carried out according to example 1 at a molar ratio HF:C2, the Rafa 3).

Example 3.

The ferric chloride solution was prepared in a reactor with a stirrer. The reactor was loaded 1.34 kg Fl36N2O and of 1.16 l of distilled water. The solution was stirred at a temperature of 60oC for 1 h and cooled to room temperature.

In the mixer was loaded 13,0 kg of magnesium fluoride, prepared according to example 1, rl36N2O number 6,38 kg, was stirred for 15 min and loaded the prepared solution of ferric chloride.

Mixing, molding and drying of the granules of the catalyst was carried out according to example 2.

The finished catalyst contained (in terms of metal) to 9.0 wt.% Cr (III) and 2.0 wt.% Fe (III), magnesium fluoride - rest.

Activation and testing of the catalyst was carried out according to example 1 at a molar ratio HF: C2Cl4= (9,7-13,2): 1. Conversion of perchloroethylene was $ 81.8-up 85.2%, the selectivity for the amount of freon 123, 124, 125 - 66,8-74,4% (see tab.3, columns 5 and 6).

Example 4.

The solution of the chlorides of iron and zinc was prepared in a reactor with a stirrer. The reactor was loaded 0.67 kg FeCl36H2O, then 0,29 kg ZnCl2and 1.43 l of distilled water. The solution was stirred at a temperature of 60oC for 1 h and cooled to room those whoO number 6,38 kg, and after stirring for 15 min was added freshly prepared solution of a mixture of chlorides of iron and zinc.

Mixing, molding paste and drying the granules of the catalyst was carried out according to example 2.

The finished catalyst contained (in terms of metal) to 9.0 wt.% Cr (III), 1.0 wt.% Fe (III) and 1.0 wt.% Zn (II), magnesium fluoride - rest.

Activation and testing of the catalyst was carried out according to example 1 at a molar ratio HF: C2Cl4=13,0:1 and the contact load of 0.35 kg)2CL4/(kg)cath). Conversion of perchloroethylene was 87,3%, the selectivity for the amount of freon 123, 124, 125 - 75,4% (see tab. 5, column 4).

Example 5.

The solution of the chlorides of iron and zinc was prepared in a reactor with a stirrer. The reactor was loaded 0.28 kg Fl36N2O, 0.32 kg ZnCl2and 1.60 l of distilled water. The solution was stirred for 1 h

In the mixer was loaded 13,0 kg of magnesium fluoride prepared in example 1, then rl36N2O number 6,35 kg After stirring for 15 min uploaded prepared solution of a mixture of chlorides of iron and zinc.

Mixing, molding paste and drying the granules of the catalyst was carried out according to example 1.

Ready the I.

Activation and testing of the catalyst was carried out according to example 1 at a molar ratio HF: C2Cl4=10,5:1 and the contact load 0,41 kg)2CL4/(kg)cath). Conversion of perchloroethylene was 77.2 percent, the selectivity for the amount of freon 123, 124, 125 - 85,5% (see tab. 5, column 2).

Example 6.

In a reactor with a stirrer was loaded 19,0 kg basic magnesium carbonate, 0.27 kg Fl36N2O and 0.52 kg ZnCl2. Was added to 57.0 l of distilled water and 21.2 kg of hydrofluoric acid (40% HF). Further precipitation of salts, drying their suspensions was carried out according to example 1.

In the mixer was loaded powder obtained salts, then rl36N2O number 6,40 kg and after stirring for 15 min uploaded 1,62 l of distilled water.

Mixing, molding paste and drying the granules of the catalyst was carried out according to example 2.

The finished catalyst contained (in terms of metal) to 9.0 wt.% Cr (III), 0.4 wt.% Fe (III) and 1.8 wt.% Zn (II), magnesium fluoride - rest.

Activation and testing of the catalyst was carried out according to example 1 at a molar ratio HF: C2Cl4=13,3:1 and the contact load of 0.32 kg)2CL4/(kg)cath). Conversion of perchloroethylene was 80,0%, selectionlistener 5, were treated with nitrogen and activated hydrogen fluoride as in example 1.

Hydroperiodide subjected tetraphthalate under the following conditions: temperature 400oWith excess pressure of 0.3 MPa, the molar ratio of HF: C2HClF4=7:1, the contact load of 0.5 kg C2HClF4/ (kg)cath).

Under these conditions the conversion of TETRAFLUOROMETHANE amounted to 90.0%, the selectivity to HFC - 125-95,7% (see tab. 6, column 3).

Example 8.

The catalyst was prepared according to example 5, was treated according to example 1.

Hydroperiodide subjected trifenilamin under the following conditions: temperature 404oWith excess pressure of 0.3 MPa, the molar ratio of HF:2HCl2F3=6:1, the contact load of 0.4 kg C2HCl2F3/ (kg)cath).

Under these conditions the conversion of trifter dichloroethane was 95.1% and the selectivity to HFC 125-53,9% (see tab. 6, column 2).

Example 9.

The solution of the chlorides of iron and zinc was prepared in a reactor with a stirrer. The reactor was loaded 0.33 kg FeCl36H2O, then 0,29 kg ZnCl2and 2.4 liters of distilled water. The solution was stirred at a temperature of 60oC for 1 h and cooled to room rate isO in the amount of 3.75 kg, and after stirring for 15 min was added freshly prepared solution of a mixture of chlorides of iron and zinc.

Mixing, molding paste and drying the granules of the catalyst was carried out according to example 2.

The finished catalyst contained (in terms of metal) to 9.0 wt.% CR(III), 0.5 wt.% Fe (III) and 1.0 wt.% Zn (II), magnesium fluoride - rest.

Activation and testing of the catalyst was carried out according to example 1 at a molar ratio HF: C2Cl4=13,0:1 and the contact load of 0.35 kg)2CL4/(kg)cath). Conversion of perchloroethylene was 83.2%, the selectivity for the amount of freon 123, 124, 125 - 82,3%.

Example 10.

The solution of nitrate of iron and of zinc chloride was prepared in a reactor with a stirrer. The reactor was loaded 0,44 kg Fe(NO3)36H2O, then 0.43 kg ZnCl2and 1.56 liters of distilled water. The solution was stirred at a temperature of 60oC for 1 h and cooled to room temperature.

In the mixer was loaded 13,0 kg of magnesium fluoride produced according to example 1, shestibalny chloride chromium in the amount 6,40 kg and after stirring for 15 min was added freshly prepared solution of a mixture of iron nitrate and chloride of zinc.

Mixing, molding pastes the metal) of 9.0 wt.% CR (III), 0.5 wt.% Fe (III) and 1.0 wt.% Zn (II), magnesium fluoride-rest.

Activation and testing of the catalyst was carried out according to example 1 at a molar ratio HF: C2Cl4=13,0:1 and the contact load of 0.35 kg)2CL4/(kg)cath). Conversion of perchloroethylene amounted to 81.6%, the selectivity for the amount of freon 123, 124, 125 - 84,4%.

Example 11.

The chromium hydroxide composition CR(OH)33H2O in the amount of 3.75 kg was subjected to heat treatment at a final temperature of 200oWith and received monohydroxy chromium composition of the UNCT.

The solution of nitrate of iron and of zinc chloride was prepared in a reactor with a stirrer. The reactor was loaded 0.27 kg Fe(NO3)36H2O, then 0,35 kg ZnCl2and 3.2 l of distilled water. The solution was stirred at a temperature of 60oC for 1 h and cooled to room temperature.

In the mixer was loaded 13,0 kg of magnesium fluoride produced according to example 1, monohydroxy chromium in the amount of 2,03 kg and after stirring for 15 min was added freshly prepared solution of a mixture of iron nitrate and chloride of zinc.

Mixing, molding paste and drying the granules of the catalyst was carried out according to example 2.

The finished catalyst contained (in terms of IU is Isadora was carried out according to example 1 at a molar ratio HF: C2Cl4=11,2:1 and the contact load of 0.35 kg)2CL4/(kg)cath). Conversion of perchloroethylene accounted for 77.3%, the selectivity for the amount of freon 123, 124, 125 - 85,7%.

Example 12.

The ferric chloride solution was prepared in a reactor with a stirrer. The reactor was loaded 0.33 kg FeCl36H2O, then 2.5 l of distilled water. The solution was stirred at a temperature of 60oC for 1 h and cooled to room temperature.

In the mixer was loaded 13,0 kg of magnesium fluoride produced according to example 1, the zinc hydroxide in the amount of 0.21 kg, was added 0.6 l of distilled water and stirred for 0.5 h Then the mixer was loaded CR(OH)33H2O in the amount of 3.75 kg, and after stirring for 15 min was added freshly prepared solution of ferric chloride.

Mixing, molding paste and drying the granules of the catalyst was carried out according to example 2.

The finished catalyst contained (in terms of metal) to 9.0 wt.% CR (III), 0.3 wt.% Fe (III) and 1.1 wt.% Zn (II), magnesium fluoride - rest.

Activation and testing of the catalyst was carried out according to example 1 at a molar ratio HF: C2Cl4=13,0:1 and the contact load of 0.35 kg)2CL4/(kg)cath). Conversion perchlorates, containing compounds of chromium (III) and carrier - magnesium fluoride, characterized in that the catalyst additionally contains compounds of iron (III) and, optionally, zinc (II) in the following ratio of components, in terms of metals, wt. %:

Iron (III) - 0,1-2,0

Zinc (II) - 0-2,0

Chromium (III) is 6.5 to 12.0

Magnesium fluoride - Rest

 

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