SU895924A1 - Method of producing boron oxide-containing aluminium phosphate - Google Patents

Description

one

This invention relates to a process for producing aluminum phosphate containing boron oxide with a high specific surface area, which can be used as a catalyst and adsorbent.

Known method 1 is the preparation of an aluminophosphate binder containing boron oxide as a result of the interaction of aluminum hydroxide with an phosphorus of acid with a density of 1.42 g / cm and a finely ground boric acid. . The mixture is dried, stirring occasionally with up to constant weight. and calcined at 150-900 ° C. The prepared compositions have a molar ratio: Ppo 1: 3:: (0.25-0.6).

The disadvantage of this method is the low specific surface area of the obtained aluminophosphate bonds due to the transition of the latter to a condensed state upon heating.

There is also known a method for producing aluminum phosphate containing boron oxide (15 wt.% Of the total content of Ae, p? + Aep04) I consisting in the activated gel of aluminum phosphate impregnated with a methanol solution of boric acid and calcined at 1200 ° F for 3 h, moreover, the gel of aluminum phosphate (33 wt.% ,, 67 wt.% A2P04) with a specific

 surface 458 is produced by reacting an aqueous solution of aluminum chloride or nitrate and phosphoric acid with ethylene oxide at a temperature of 0-5 ° C, followed by

10 by extruding the hydrogel precipitated with a water-soluble organic solvent, drying and activating for 48 hours at 1,400 ° F 2.

The disadvantage of this method is the low specific surface area of the product obtained (272 Mvr) and the complexity of the process due to the use of an explosive precipitator — ethylene oxide, gel extraction with a water-soluble organic solvent, and impregnation of the activated gel with a toxic methanol solution of boric acid.

The purpose of the invention is to increase the specific surface of the product and simplify the process.

The goal is achieved by the method of obtaining aluminum phosphate containing boron oxide, which consists in the interaction of solutions

aluminum nitrate and phosphoric acid with the introduction of boric acid at a molar ratio of A2 (NOg) o,: H jPC: NlVOz, equal to 1: (0.08-0.5) :( 0.081, 47), precipitating urea hydrogel at 100-120s , drying and calcining the product.

The specific surface of the obtained samples is determined by chromatographic method by thermal desorption of argon.

The proposed method is characterized by the dissolution of boric acid in the initial mixture of reagents at a given ratio of components and the precipitation of hydrogel with urea at 100-120 ° C, with the exception of the stage of washing the hydrogel. The introduction of boric acid in an amount less than 0.08 mol in the mixture of reagents (3.12 wt.% Of the total content + AbRO does not provide a sufficiently high specific surface. The introduction of boric acid in the amount of 1.47 mol in the mixture of reagents (44.5 wt. % iji of the total content + ACROD.) results in a decrease in the specific surface area of the product obtained, and therefore an increase in the amount of boric acid injected above this norm. It is not advisable. Hydrogel is deposited with urea at 100-120 ° C. At a temperature below, the precipitation process It does not go well, at a temperature keeping the solution less, the gelation process slows down a lot.The upper limit of the temperature — boiling temperature — in this case is determined by the properties of the solution and does not exceed 120 ° C.

The time required for precipitation of the hydrogel depending on the temperature for example 2 is given below. Temperature Time Formation

gel h

precipitation, "C

The gel does not form 85 with

96

90 95

48

24 120

The proposed method allows: to simplify the process by eliminating the extraction stage of a hydrogel with a water-soluble organic solvent to obtain samples with high specific surface (516-630 m / g) Introducing boron oxide directly into the initial reagent solution allows eliminating the stage of impregnating aluminum phosphate gels with toxic methanol boric acid solution. The proposed method provides a significant development of the specific surface of the product obtained, exceeding in this Indicator not only aluminum phosphate containing boron oxide, obtained by a known method, but also gel-like aluminum phosphates that do not contain boron oxide. The presence of boric anhydride in the aluminum phosphate obtained by the proposed method enhances the acidic properties of these catalysts and the possibility of changing the tetrahedral coordination of boron to triangular and vice versa allows the number of reactions catalyzed by such a product to be expanded.

Example 1. 100 MP of a 2 M solution of aluminum nitrate are mixed with 8 ml of 2 M phosphoric acid, 0.99 g of boric acid (which is 4.68% by weight of Boo, based on the total content + AERO and corresponds to the molar ratio) is dissolved by heating. A2 (NOj) gNDRO tHjBO, equal to 1: 0.08: 0.08), injected 19.0 g of crystalline urea and kept at 100 ° C for 16 hours until a hydrogel is formed. The gel formed is dried at 100 ° C, calcined for 5 hours. The specific surface of the obtained sample is 550 MVr, and the yield is 98%.

Example 2. 100 ml of a 2 M solution of aluminum nitrate are mixed with 50 ml of 2 M phosphoric acid, dissolving 0.99 g of boric acid (which is 3.12 wt.%) From the total content + + ASPOj and corresponds to a molar ratio of A (NO 3) 1:: H: H SOF = 1: 0.5: 0.08), 24.0 g of crystalline urea are introduced and kept at 120 ° C for 24 hours until a hydrogel is formed. The gel formed is dried at 100-110 ° C, calcined at 500 ° C for 5 hours. The specific surface of the obtained sample is 516 MVr, yield 98%.

Example 3. 100 ml of a 2 M solution of aluminum nitrate are mixed with 18 ml of 2 M phosphoric acid, and 7.79 g of boric acid (which is 25.58% by weight of BfLOii from the total content of A, + + AEROd) is dissolved by heating. and corresponds to the molar ratio of A8 (NOj) Oi: H / i, PO4, equal to 1: 0.18: 0.62), 20.2 g of crystalline urea are introduced and incubated for 12 hours at 100 ° C to form a hydrogel. The gel is dried at 100-110 ° C, calcined at 5 hours. The specific surface of the obtained sample is 630, yield 96.5%.

Example 4. 100 ml of a 2 M solution of aluminum nitrate are mixed with 50 ml of 2 M phosphoric acid, dissolved by heating 7.79 g of boric acid (which is 20.22% by weight, of the total content, + AgRO4 and corresponds to the molar ratio AB (NOvj),: Hb, P04 i., Equal to 1: 0.5: 0.63), are introduced

.24 g of crystalline urea and kept at 100 ° C for 9 hours to form a hydrogel. The gel formed is dried at lOO-llO C, calcined at 500 ° C for 5 hours. The specific surface of the obtained sample is 524 MVr, yield 96.5%.

Example 5. 100 ml of a 2 M solution of aluminum nitrate are mixed with 18 ml of 2 M phosphoric acid, dissolved with heating 18.17 g of boric acid (which constitutes 44.51% by weight of BnOj of the total content and corresponds to the molar ratio A (NOj ) .H-jPO tHjBO, equal to 1: 0.18:

: 1.47), 20.2 g of crystalline urea are introduced and kept at. for 6 hours before hydrogel formation. The resulting gel is dried at lOO-llO C, calcined for 5 hours. The specific surface of the sample is 580 MVr g and the yield is 96%.

The table shows the specific surface area of the obtained samples depending on the ratio A (N0-1) 51: H3PO4, H5BOO, and Ae (NH3) h: (+ H, jBO2,) and the content of the total AB Oi + ASPO ..

Prototype

From the data in the table it follows that the proposed ratios of the components allow to obtain a product with a high specific surface that exceeds the specific surface of the samples obtained by the known method by 90–130%. Production of aluminum phosphate containing boron oxide with a high specific surface makes it more preferable as a sorbent material (the sorption capacity for water vapor and carbon dioxide increases significantly for samples with a larger catalyst and because for a number of processes the activity of the catalyst is in direct depending on the value of the specific surface.

The proposed method is easier known, since it eliminates the use. explosive precipitator as well. washing with water-soluble organic-KIM solvent and impregnation toxic,

272

15

with methanol solution of boric acid.

Claims (2)

Invention Formula A method of producing aluminum phosphate containing boric oxide by reacting an aqueous solution of aluminum nitrate and phosphoric acid, which includes the introduction of boric acid, the precipitation of a hydrogel, the drying and calcination of the product, characterized in that, in order to increase the specific surface of the product and simplify the process, into a solution of nitric acid aluminum and phosphoric acid are injected with boric acid at a molar ratio of aluminum nitrate, phosphoric acid and boric acid, equals: (0.08-0.5) s (0.08-1.47), and the hydrogel is precipitated by urea 100-120S. Sources of information taken into account during the examination 1. Tikavy VF et al. Effects on thermal transformations of the ayu-v i-S - iplnpg A9PH1-1g-n from the current. Lime mophosphate binder. Lime USSR Academy of Sciences. Inorganic materials, v. 9, No. 9, 1608, 1973. 2. US patent No. 3342750, CL.252-437, published. 09/19/67 (prototype).