How hydroisomerization n-paraffins with a long chain bifunctional catalyst, methods of making the catalyst

 

(57) Abstract:

Usage: petrochemistry. Entity: n-paraffins with the number of carbon atoms higher than 15 will isomerized in the presence of hydrogen and a catalyst comprising: a) a carrier of acid nature, consisting of a gel of silicon dioxide and aluminum oxide, amorphous to x-rays, with a molar ratio of SiO2/Al2O3in the range of from 30/1 to 500/1, and having a surface area in the range from 500 to 1000 m2/g, a porosity in the range from 0.3 to 0.6 ml/g and a pore diameter in the range of 10-40 And; (b) a mixture of VI metals and base metals of the VIII group, deposited on the carrier in a total amount of from 2 to 50 weight. % of the total weight of a) + b). Describes how to obtain the catalyst. The technical result is an increase in the activity of the catalyst, resulting in increased efficiency of the method. 3 S. and 11 C.p. f-crystals, 3 tables.

The invention relates to a method of hydroisomerization n-paraffins with a long chain.

More specifically, the present invention relates to a method of hydroisomerization n-paraffins with the number of carbon atoms higher than 15, for example between 15 and 60, and a catalyst suitable for this purpose.

The way isomerization of waxes to obtain core is whether suitable catalysts. In fact, it is necessary to turn waxes mainly composed (more than 70-80 wt.%) from n-paraffins with the number of carbon atoms higher than 15, and therefore solid at room temperature, into the corresponding branched isomers, which have a lower melting point than linear, for example, C16n-paraffin has a melting point of 19oC, whereas the isomeric 5-methylpentadiene melts at -31oC.

Effective catalyst hydroisomerization however, should minimize the possible reactions of cracking and hydrocracking, which kataliziruetsa the same acidic centers and, similarly, the reaction of hydroisomerization proceeding with the formation of the intermediate carbocations. These secondary reactions cause a decrease in molecular weight with the formation of lighter products of inferior quality, which must be separated from the final product. Obviously, this is a shortcoming of the method in General.

To overcome this limitation have been developed bifunctional catalysts hydro-dehydrogenization, i.e. catalysts containing acid sites and active sites, which usually has a metallic nature. The acidity of such katal is gidrogenization activity of the catalyst is provided by a metal phase, deposited on the carrier. This metal phase also gives the catalyst function minimize cracking.

It was shown that (J. F. Le Page, Applied Heterogeneous Catalysis, Ed.Technip, 1987, 435-466) at the same hydrogenating activity of the most selective are those catalysts in which the media is controlled acidity that maximizes the isomerization of n-paraffins in the cracking. However, since the isomerization is accompanied by reactions of cracking, the maximum selectivity for isomerization is achieved at low levels of conversion (G. Froment et al. Ind. Ehg. Chem. Prod. Res. Dev., 1981, 20, 654-660). In any case, the efficiency of different catalysts evaluated using model compounds such as n-paraffins, measuring their selectivity, i.e. the ratio between the products of isomerization and cracking, in particular the conversion of n-paraffins.

From the scientific literature known catalysts and methods of hydroisomerization paraffin waxes. For example, in U.S. patent 5049536 or published applications to the European patent 582347 and 659478 described catalysts based gel of silica and alumina, possibly modified with metals of group VIIIA, particularly palladium and platinum, and their note is merisalo using catalysts based on noble metal paraffin waxes, used as source material subject isomerization comes from processes of production of lubricating oils and form a by-product of extraction with solvents such as methyl ethyl ketone (MEK), toluene, or mixtures thereof. This material has a high content of sulfur and nitrogen compounds and polynuclear aromatic compounds, which have a negative impact on the lifetime and activity of this group of catalysts. In fact, sulfur compounds poison the catalyst, transforming the noble deposited metals into the corresponding sulfides, nitrogen compounds reduce the activity of the catalyst by blocking the acid sites, whereas polynuclear aromatic compounds act as precursors of coke deposited on the catalyst surface causes a decrease of its activity.

To overcome these disadvantages, subject to hydroisomerization n-paraffins undergo the process of hydrogenation, whose main purpose is the removal of much of the sulfur and nitrogen compounds. In this regard, it should be noted that to prevent the rapid decline in catalyst activity usually remove toxic compounds should be in the organization as a whole.

Currently, a method was found of hydroisomerization n-paraffins, which includes the use of a new catalyst, such as active as catalysts based on noble metals, but more resistant to toxic agents present in the waxes to be hydroisomerization.

Therefore, the present invention relates to a method of hydroisomerization n-paraffins with a long chain, which involves the isomerization of n-paraffins with the number of carbon atoms higher than 15, in the presence of hydrogen and catalyst hydroisomerization, which contains:

a) a carrier of acid nature, consisting of a gel of silicon dioxide and aluminum oxide, amorphous to x-rays, with a molar ratio of SiO2/Al2O2in the range of from 30/1 to 500/1, and having a surface area in the range from 500 to 1000 m2/g, a porosity in the range from 0.3 to 0.6 ml/g and a pore diameter in the range of 10-40 angstroms;

b) a mixture of metals belonging to groups VIB and VIII deposited on the carrier in a total amount of from 2 to 50% by weight of the total weight of a) + b).

In a preferred variant embodiment of the present invention the acid catalyst carrier has a ratio of SiO2/Al2O3

Media-based gel of silica and alumina can be conveniently obtained in accordance with the method described in U.S. patent 5049536 or published the application for the European patent EP 659478. In particular, obtain an aqueous solution of tetraalkylammonium hydroxide (TAA-OH), where alkyl is, for example, n-propylene or n-butile, soluble aluminum compounds capable of either hydrolyzed in aluminum oxide and a soluble silicon compound capable of either hydrolyzed in silicon dioxide and the quantity of these components in the solution is such as to comply with the following molar relationship: SiO2/Al2O3from 30/1 to 500/1;

TAA-OH/SiO2from 0.05/1 to 0.2/1;

H2O/SiO2from 5/1 to 40/1.

Thus obtained solution is heated to cause its gelatinization. The resulting gel is dried and calcined in an inert atmosphere and then in an oxidizing atmosphere.

The acid catalyst carrier of the present invention can be applied as such or in the form of an extrudate. In the last sludent EP 550922 and EP 665055, which include the use of a ligand consisting of inert solids, such as aluminum oxide. In particular, the carrier and the ligand can be pre-mixed in a weight ratio varying from 30:70 to 90:10, preferably from 50:50 to 70:30. At the end of mixing the resulting product utverjdayut in the desired final form, for example in the form of extruded cylinders or pellets.

The metal phase (b) of the catalyst of the present invention may be introduced by water or alcohol treatment.

More specifically, in accordance with the first method, the gel of silica and alumina, also in extruded form, obtained as described above, moistened with an aqueous solution of compound VIB metal, for example molybdenum ammonium, working at room temperature or close to it temperature. After water impregnation, the solid is dried, preferably in air, at a temperature of about 100oC and then carry out a second impregnation with an aqueous solution of compounds of non-precious metal of group VIII, for example acetate or Nickel nitrate.

After water impregnation, the solid is then dried, preferably in air, at a temperature of BlackBerry, suitable for this heat treatment ranges from 200 to 600oC. Conditions govern so that particles of silicon dioxide and aluminum oxide to precipitate the metal of group VIII in an amount of from 0.5 to 5 wt.%, preferably from 1 to 3 wt.%, and the metal of group VIB in the amount of from 1 to 50 wt.%, preferably from 5 to 35 wt.%.

The aqueous impregnation of the metal phase can also be carried out in one stage, in which the acid medium on the basis of silicon dioxide and aluminum oxide moisten a single aqueous solution containing compounds of metals of group VIB and group VIII, and operate according to the same methods described above.

Using the methods of alcohol impregnation of the gel of silica and alumina also in extruded form, is suspended in an alcohol solution of compound VIB metal, for example molybdenum acetylacetonate, and the connection of the metal of group VIII, such as Nickel acetylacetonate, working at room temperature or at a similar temperature. After impregnation, the solid is dried, preferably in air, at a temperature of about 100oC and thermally treated in an oxidizing atmosphere, preferably in air, as in point is the Torah gel silicon dioxide and aluminum oxide, loaded (containing) a mixture of metals VIB and VIII groups, typically having a surface area of from 150 to 350 m2/g in the case of extruded media and from 250 to 500 m2/g in the case of a gel.

Thus obtained catalyst is activated by sulfatirovnie. The process of sulfatirovnie carried out in a reducing atmosphere of hydrogen sulfide/hydrogen at a temperature of 300-500oC, and by treatment with carbon disulfide in the recovery atmosphere again at a temperature in the range from 300 to 500oC.

The reaction hydroisomerization can be carried out both continuously and intermittently. It is conducted in the presence of hydrogen at a temperature in the range from 200 to 550oC, preferably from 250 to 450oC and at a pressure of hydrogen in the range from atmospheric to 25,000 KPa, preferably from 4,000 to 10,000 KPa.

An effective amount of catalyst is usually between 0.5 and 30 wt.%, preferably between 10 and 20 wt.%, relative to n-paraffins.

For a better understanding of the present invention and its embodiments provides some illustrative, but not limiting, examples.

Example 1

At room temperature dissolve 2 g ist at 60oC and add 104,1 g tetraethylsilane (TEC). The resulting mixture has the following molar relationship: SiO2/Al2O3= 102, TPA-OH/ SiO2= 0,09 and H2O/SiO2= 15.

While maintaining the mixture under stirring at 60oC for 40 minutes, the formation of a homogeneous gel, which is dried in a stream of air at 90oC and then calcined at 550oC in a stream of nitrogen for 3 h and then in a stream of air for an additional 10 h at the same temperature.

Get gel silicon dioxide and aluminum oxide, amorphous in x-ray radiation, with a quantitative yield relative to the downloaded source materials.

The active phase on the basis of silicon dioxide and aluminum oxide, which is linked to an inert carrier of alumina, the last number is 39 wt.%, and ekstragiruyut into cylindrical pellets.

Thus obtained material is used as the acid medium, which precipitated metals using an aqueous impregnation. More specifically, 20 ml of an aqueous solution containing 1.3 g MO7(NH4)6O246H2O. the Mixture is left to mix for 16 h, then evaporated water s 4 hours in a stream of air, the heating rate was 3oC per minute.

Research data catalyst are shown in table 1.

Example 2

Use the media as in example 1, using as a deposition method of the metal phase joint impregnation.

Dropwise add 22 ml of an aqueous solution of 1 g of Ni(CH3OO)24H2O and 10 g MO7(NH4)6O24< / BR>
The selectivity for C16- =

where ISO-C16is a mixture of isomers with the number of carbon atoms equal to 16, and C16- is a mixture of cracking products with the number of carbon atoms is less than 16.

Activation of the catalyst

In the autoclave with 10 ml n-C16and 1 ml of carbon disulfide (CS2upload 0.55 g of catalyst, to obtain in situ hydrogen sulfide required for sulfatirovnie. Then the reactor was pressurized at room temperature and create a hydrogen pressure of 8 atmospheres and heated to 370oC at a rate of 10oC / minute, while stirring the mixture with a speed of 800 Rev/min Sulfatirovnie lasts for 4 h at the final temperature.

Upon completion stage activation relieve pressure in the reactor and the mixture is filtered to separate the catalyst. Then katalizatoriai C16n-paraffins using a catalyst according to example 2. Reaction conditions support as in example 7. Data conversion and selectivity are shown in table. 2.

Example 9

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 3. Reaction conditions support as in example 7. Data conversion and selectivity are shown in table. 2.

Example 10 (comparative)

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 4. Reaction conditions support as in example 7. Data conversion and selectivity are shown in table. 2.

Example 11 (comparative)

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 5. Reaction conditions support as in example 7. Data conversion and selectivity are shown in table. 2.

Example 12 (comparative)

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 5. Reaction conditions support as in example 7, except that the reaction time is reduced to 480 minutes. Data conversion and selectivity are shown in table. 2.

Example 13 (comparative)

In rederived, as in example 7. Data conversion and selectivity are shown in table. 2.

Example 14

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 2. Reaction conditions support as in example 7, except that the reaction time is reduced to 480 minutes. Data conversion and selectivity are shown in table. 3.

Example 15

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 1. Reaction conditions support as in example 14. Data conversion and selectivity are shown in table. 3.

Example 16.

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 1. Reaction conditions support as in example 14, except that the reaction temperature is reduced to 345oC. Data conversion and selectivity are shown in table. 3.

Example 17 (comparative)

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 4. Reaction conditions support as in example 14. Data conversion and selectivity are shown in table. 3.

Example 18 (comparative)

In the reaction of hydroisomerization C16n-paraffins andthat the reaction temperature is reduced to 345oC. Data conversion and selectivity are shown in table. 3.

Example 19 (comparative)

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 2. Reaction conditions support as in example 7, except for the boot, which is composed of 97 wt.% n-C16and 3% studied. Data conversion and selectivity are shown in table. 3.

Example 20 (comparative)

In the reaction of hydroisomerization C16n-paraffins using a catalyst according to example 5. Reaction conditions support as in example 19 except that the reaction time is reduced to 240 minutes. Data conversion and selectivity are shown in table. 3.

1. How hydroisomerization n-paraffins with a long chain by isomerization of n-paraffins with the number of carbon atoms higher than 15 in the presence of hydrogen and of a catalyst containing a carrier of acid nature, consisting of a gel of silicon dioxide and aluminum oxide, amorphous to x-rays, with a molar ratio of SiO2/Al2O3in the range of from 30/1 to 500/1, having a surface area in the range from 500 to 1000 m2/g, a porosity in the range from 0.3 to 0.6 ml/g and a pore diameter in the range of 10 - 40 otlichuy the different metals of group VIII, deposited on the carrier in a total amount of from 2 to 50 wt.% of the total weight of a) +b).

2. The method according to p. 1, wherein the acidic medium has a ratio of SiO2/Al2O3in the range of from 50/1 to 300/1 and porosity in the range from 0.4 to 0.5 ml/g

3. The method according to p. 1 or 2, characterized in that the mixture of metals (b) consists of metal VIB group selected from molybdenum and tungsten, in an amount of 5 to 35 wt.%, and base metal of group VIII selected from Nickel and cobalt, in an amount of from 0.1 to 5 wt.%.

4. The method according to any of the preceding paragraphs, characterized in that the acid media and used as such or in extruded form.

5. The method according to p. 4, characterized in that the extruded carrier pre-mixed with ligand consisting of inert solids, and utverjdayut into the desired final shape.

6. The method according to any of the preceding paragraphs, characterized in that the reaction hydroisomerization carried out in the presence of hydrogen at a temperature in the range from 200 to 550oC and a hydrogen pressure in the range from atmospheric to 25,000 KPa.

7. The method according to any of the preceding paragraphs, characterized in that the catalyst is the catalyst for hydroisomerization n-paraffins with a long chain including a carrier of acid nature, consisting of a gel of silicon dioxide and aluminum oxide, amorphous to x-rays, with a molar ratio of SiO2/Al2O3in the range of from 30/1 to 500/1, and having a surface area in the range from 500 to 1000 m2/g, a porosity in the range from 0.3 to 0.6 ml/g and a pore diameter in the range of 10 to 10 characterized in that the catalyst contains a) specified media and (b) a mixture of metals of the VI group and base metal of group VIII deposited on a support in the summatory number from 2 to 50 wt.% of the total weight of a) + b).

9. Bifunctional catalyst under item 8, characterized in that it contains a carrier of acid nature with respect to SiO2/Al2O3in the range of from 50/1 to 300/1 and porosity in the range from 0.4 to 0.5 ml/g

10. Bifunctional catalyst according to PP.8 and 9, characterized in that it contains a mixture of metals consisting of metal VI group selected from molybdenum and tungsten, in an amount of 5 to 35 wt.% and base metal of group VIII selected from Nickel and cobalt, in an amount of from 0.1 to 5 weight. %.

11. The method of producing catalyst according to PP.8 - 10, consisting in: (i) wetting gel silicon dioxide and aluminum oxide, also in ek who spent so gel silicon dioxide and aluminum oxide; (iii) impregnating the dried gel of silica and alumina with an aqueous solution of compounds of non-precious metal of group VIII; (iv) drying the thus treated gel silicon dioxide and aluminum oxide; and (v) thermal treatment of the dried gel in an oxidizing atmosphere at a temperature in the range from 200 to 600oC.

12. The method of producing catalyst according to PP.8 - 10, consisting in: (i) wetting gel silicon dioxide and aluminum oxide, also in extruded form, with an aqueous solution of metal joining VI and connections base metal of group VIII at room temperature; ii) drying the thus treated gel silicon dioxide and aluminum oxide; (iii) heat treatment of the dried gel in an oxidizing atmosphere at a temperature in the range from 200 to 600oC.

13. The method of producing catalyst according to PP.8 - 10, consisting in: (i) suspendirovanie gel silicon dioxide and aluminum oxide, also in extruded form, in an alcohol solution of metal joining VI and connections base metal of group VIII at room temperature; ii) drying the thus treated gel silicon dioxide and aluminum oxide; (iii) heat treatment vysushennogo is from PP.11 - 13, consists in the fact that the catalyst is activated by sulfatirovnie.

 

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