SU265865A1 - METHOD OF PREPARATION OF ALUMONICELICHROM - Google Patents

Description

A known method for preparing an alumoniel-chromium skeletal catalyst promoted with iron with an oxidized surface for the hydrogenation of aromatic hydrocarbons by leaching aluminum with a iron chromium alloy followed by treating the alloy with air or oxygen at elevated temperatures.

In order to obtain a catalyst with high activity, a long service life and resistance to poisonous impurities, a method has been proposed, which involves the addition of an alkali metal, preferably potassium, in the amount of up to 4 wt. 7oPredolicy catalyst provides hydrogenation of sulfur-containing raw materials with the addition of detoksikant - nitrogen-containing substances. At the same time, the excess of nitrogenous detoxicate, due to the content of alkali metal in the catalyst, does not exhibit its own properties, but is hydrogenated to the corresponding pasacular compound.

The essence of the method of catalyst preparation is that the crushed metal alloy of aluminum, nickel, chromium, iron and alkali metal is leached with an aqueous solution of caustic soda in the usual way, then the surface of the active catalyst is covered with an appropriate oxide film by heating in the presence of oxygen.

Example. A crucible made of refractory material is loaded with purified aluminum chips (55 g) and placed in a Ptchti electric furnace heated to 1000-1100 ° C. After the nlavlepi alumipi, slag is removed from the surface of the melt and the metal nickel chips (32 g) and chip, single metallic iron (1 g) are deposited on the surface of the melt. Poroitic chromium (10 g) is added at the time of nickel melting. To achieve full melted components, they are mixed using porcelain and a small cup.

After the components have completely melted, the crucible is removed from the nec, cooled to 700–775 ° C (but the color is calepane) and the vials are mixed with alkali metal, the potassium metallic substance (2 g), which melts instantaneously. Then the melt is sliced into a tin pan. To achieve rapid cooling, the baking tray with the contents is dipped in cold water. The alloy is crushed to 3–5 mm pieces and activated with a vodopim solution of sodium hydroxide with the usual method. In this way, the catalyst that is quivirovanized is washed with distilled water to a neutral reaction,

dried and slowly oxidized in a stream of nitrogen containing oxygen impurities. The final oxidation of the newer batch is produced in a muffle furnace at 580-600 ° C in air or better than oxygen for 6-8 hours.

Before starting the catalyst in the reactor, iodine is activated by a small hydrogen pressure at 400–450 ° C for 4–5 hours.

In the presence of a skeletal alumina nickel-chromium catalyst with an oxidized surface, such as iron and potassium, it is possible to carry out hydrogenation reactions of some aromatic hydrocarbons (benzene, toluene, and xylenes) and dealkylation of toluene in the presence of water iars.

Hydrogenation is carried out at a high pressure setting with loading of a 0.25 L catalyst and a bulk volume into the reactor. A temperature of 200-225 ° C (in the case of benzene, 80 ° C), a hydrogen pressure of 7 m / m, a volumetric transmission rate of 0.5 h -1 is recommended for hydrogenation.

Pyridine is added to the hydrogenated feedstock (iairimer, toluene) containing sulfuric impurities at the rate of 1 g sulfur atom 2 g nitrogen atom. In this case, it seems, shielding of the toxic effect of both serum and nitrogen compounds occurs. However, the absolutely accurate observance of the atomic ratios of 5 and l / l, equal to 1: 2, under the conditions of the mouse is not always possible. Consequently, the slightest disruption of the ratio of sulfur atoms and nitrogen leads to poisoning of the catalyst by the excess amount of organic sulfur or nitrogen organo-compounds in the reaction zone. Therefore, it is advisable to add an excess amount of the ortho-orhapic compound; , presumed, esteino pyridine, the excess of which is freely hydrogenated in the presence of the proposed catalyst containing an alkali metal, nairimer k; 1ly.

In the hydrogenation of sulfur-containing aromatic hydrocarbons, the calisator exhibits high activity and stability. If necessary, its activity can be restored by reactivation by heating at 580-600 ° C with access of oxygen.

Dealkylation of toluene in the presence of water vapor. Catalyst D amount of 100 ml

bulk volume is loaded into the reactor of the prototype type, made of stainless

become.

In the reactor, agregaty to 320-370 ° C, served

toluene and water with the appropriate dispensers. The molar ratio of toluene and water is 1: 3. A mixture of toluene and water, the passage through a layer of broken quartz glass loaded above the catalyst, evaporates and flows as vapor into the surface of the catalyst. The products of the reaction, the irohod through the refrigerator and the corresponding drain device, knock off the collection. Gaseous products are emitted into the atmosphere through a gas clock.

After removal of the catalyst, it is dried with calcined calcium chloride and is dialyzed on a gas-liquid chromatograph.

The yield of liquid and reaction products 90 wt. %

Beizol content in catalyzate 15-18 wt. %, the average composition of the gases and products,%: Pg 7; SP4 40; CO 8; Soo 15; 0.5 The inter-reactive life of the catalyst is 40-50 hours. Reactivation (burning of coke) is carried out by heating in a muffle furnace at 600 ° C with air access.

Subject invention

Method prigotovleii alyumoiikelhromovogo skeleton catalyst promotion iron with okisleiioy surface for the hydrogenation of aromatics and dialkilirovain alkylaromatic hydrocarbons by vatselachivaii alyumonikelhromzheleziogo alloy, characterized in that, to obtain a catalyst with high activity, long life and resistance to about ravl yuntim 11rimes m, an additive of alkali metal, preferably potassium, in an amount of up to 4 is introduced into the outgoing and aluminum-chromium-iron alloy. weight. %