GB2053871A - Method for producing calcium phosphate catalyst - Google Patents

Method for producing calcium phosphate catalyst Download PDF

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Publication number
GB2053871A
GB2053871A GB7925416A GB7925416A GB2053871A GB 2053871 A GB2053871 A GB 2053871A GB 7925416 A GB7925416 A GB 7925416A GB 7925416 A GB7925416 A GB 7925416A GB 2053871 A GB2053871 A GB 2053871A
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Prior art keywords
phosphate
catalyst
reaction mixture
calcium
precipitate
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GB7925416A
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GB2053871B (en
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Bitepazh J A
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Bitepazh J A
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/32—Phosphates of magnesium, calcium, strontium, or barium
    • C01B25/325—Preparation by double decomposition
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/14—Phosphorus; Compounds thereof
    • B01J27/16—Phosphorus; Compounds thereof containing oxygen, i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr
    • B01J27/18—Phosphorus; Compounds thereof containing oxygen, i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr with metals other than Al or Zr
    • B01J27/1802—Salts or mixtures of anhydrides with compounds of other metals than V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, e.g. phosphates, thiophosphates
    • B01J27/1806—Salts or mixtures of anhydrides with compounds of other metals than V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, e.g. phosphates, thiophosphates with alkaline or alkaline earth metals
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
    • C07C1/20—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms
    • C07C1/247—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms by splitting of cyclic ethers
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2527/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • C07C2527/14—Phosphorus; Compounds thereof
    • C07C2527/16—Phosphorus; Compounds thereof containing oxygen
    • C07C2527/167—Phosphates or other compounds comprising the anion (PnO3n+1)(n+2)-

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Catalysts (AREA)

Abstract

Calcium phosphate catalysts used in producing isoprene from isobutylene and formaldehyde and in dehydrating alcohols are produced by interacting a calcium salt and a phosphate in an aqueous-ammonia medium at a molar ratio of the calcium salt to phosphate of 1.5-5.0:1, separating a precipitate from the reaction mixture, shaping and drying the precipitate, the reaction mixture being treated, prior to separation of the precipitate, with phosphoric acid solution until a pH- value of 5.0-7.0 is reached.

Description

SPECIFICATION Method for producing calcium phosphate catalyst The present invention relates to the production of catalysts used, for example, when producing isoprene from isobutylene and formaldehyde, and more particularly to a method for producing calcium phosphate catalyst useful for decomposing 1,3-dioxanes, specifically 4,4-dimethyl-1 ,3-dioxane, further referred to as DMD, to isoprene, and also in dehydrating alcohols.
The present invention provides a methof for producing calcium phosphate catalyst by interacting a calcium salt and a phosphate in an aqueous-ammonia medium, separating a precipitate from the reaction mixture, followed by shaping the precipitate and its subsequent drying, wherein, according to the invention, the step of interaction of the initial components is carried out at a molar ratio of the calcium salt to phosphate of 1.5-5.0:1, the reaction mixture being treated, prior to separation of the precipitate with phosphoric acid solution until a pH-value of 5.0-7.0 is reached.
It is practicable to carry out the reaction at a molar ratio of the calcium salt to phosphate of 2.5:1.
With such a ratio of the initial components, the method permits a catalyst of high selectivity to be obtained.
It is also advisable to treat the reaction mixture, prior to separation of the precipitate, with phosphoric acid solution until a pH-value of 5.5-6.0 is reached.
Implemented under such conditions, the method for producing calcium phosphate catalyst enables to obtain a catalyst of high activity to be obtained. The DMD conversion degree amounts therewith to 96.096.6%, which is by 2025% more than that of the known methods.
These and other objects, as well as novel features of the present invention are set forth in the appended claims and the present invention will best be understood from consideration of the following detailed description of the preferred embodiments.
The proposed method for producing calcium phosphate catalyst is carried out as follows.
To produce calcium phosphate catalyst, an aqueous solution of calcium salt of the concentration of about 0.9 mole per litre and an aqueous solution of phosphate of the concentration of about 0.4 mole per litre are prepared. Immediately prior to the interaction of calcium salt and phosphate, ammonia solution intended to adjust pH-value is added to the phosphate solution.
The amount of ammonia solution is determined assuming 1.7-3.7 moles of ammonia per mole of phosphate.
The solutions of calcium salt, phosphate, and ammonia thus prepared are poured at a time into a common vessel under continuous stirring of the suspension formed, the molar ratio of calcium salt to phosphate being 1.5-5.0:1, preferably 2.5:1.
The indicated range of the calcium salt to phosphate ratio ensures preparation of the catalyst having both desired structure and composition. The resulting reaction mixture exhibits a pH-value of 8.49-9.4.
The reaction mixture resulting upon the interaction is treated with phosphoric acid solution until a pH-value amounts to 5-7, preferably 5.5-6.0. The precipitate thus resulted is separated from the reaction mixture by filtering off or centrifuging, then it is washed with distilled water to remove the calcium salt anions, shaped, and dried at 110-1 400 C.
The characteristics of the catalyst produced are as follows: selectivity of isoprene is 84.6-86.3 molar percent which is by 4-7 molar percent more as compared to that ensured by the known process; coke deposition in the course of decomposing DMD is twice as less as compared to that observed with the known process.
At an operating temperature of 3200C and space velocity of 1.0 hour, the catalyst prepared according to the proposed ensures DMD conversioan amounting to 96.0-97.0 percent, which is by 20-25 percent more than with the known method. Efficiency of the catalyst is about 0.8 t of isoprene per 1 m3 of the catalyst per hour. Due to the operating temperature decrease, operating life of the catalyst is increased up to 1,500 hours.
Characteristic examples illustrative of particular aspects of the present invention and clearly demonstrating its features and advantages are given below.
EXAMPLE 1 1.78 1. of calcium chloride aqueous solution (the calcium chloride content of 101.892 g/l) and 1.608 1. of diammonium phosphate aqueous solution (the diammonium phosphate content of 51.02 g/l) to which ammonia solution of 152.15 g/l concentration is added in a proportion of 2.33 moles of ammonia per mole of diammonium phosphate are gradually poured into a vessel provided with a stirrer.
The molar ratio of calcium chloride to diammonium phosphate is 2.5:1. Blending of the solutions is carried out for 2 hours, with the reaction mixture, which is substantially a suspension, being continuously stirred. The interaction of calcium chloride and diammonium phosphate in the aqueousammonia medium is carried out at a molar ratio of said components of 2.5:1, pH of the reaction mixture being 9.0+0.05. 150 ml of phosphoric acid of 281.26 g/l concentration is added to the suspension to reduce pH to 5.75, after which the precipitate thus obtained is separated from the reaction mixture by filtering off, washed with distilled water to remove chlorine ions, pressed into granules, and dried at approx. 1200C.
The catalyst obtained is tested under a reaction of decomposing DMD in the atmosphere of steam followed by regeneration consisting in burning-out the coke deposited every two hours of the catalyst operation. 24 cm3 of the resulting catalyst is charged into a reactor, which is substantially a quartz tube of20-26 mm. in diameter, whereupon the reactor is placed into an electric furnace. The process of DMD decomposition is carried out at an average operating temperature of 3200C for two hours, under atmospheric pressure. DMD is supplied in an amount of 24 cm3 per hour, and water, 48 cm3 per hour, which corresponds to space velocity of the DMD feeding of 1.0 hour and the DMD dilution of with steam of 1:2.
The cycle of DMD decomposition is followed by a regeneration cycle performed at a temperature of 4250C, water supply of 48 cm3 per hour, and air supply of 1 6,800 cm3 per hour.
The catalysate is analyzed by means of gas liquid chromatography. Amount of the coke deposited is determined by a conventional method. Test results are given in Table 1 below.
EXAMPLE 2 A catalyst is produced as described iun Example 1. Interaction of salts is carried out at a molar ratio of calcium chloride to diammonium phosphate of 1.5:1. Upon the addition of phosphoric acid, pH of the reaction mixture is 5.75. Testing of the catalyst is carried out in the same manner as described in Example 1.
Test results are given in Table 1 below.
EXAMPLE 3 A catalyst is produced as described in Example 1. Interaction of salts being carried out at a molar ratio of calcium chloride to diammonium phosphate of 5.0:1, pH of the reaction mixture upon the addition of phosphoric acid being 5.75.
Testing of the catalyst is carried out in the same manner as described in Example 1.
Test results are given in Table 1 below.
EXAMPLE 4 A catalyst is produced in the way analogous to that described in Example 1 , the molar ratio of calcium chloride to diammonium phosphate being 2.5:1. The reaction mixture obtained is treated with phosphoric acid until a pH-value is reduced to 7.0.
Testing of the catalyst produced is carried out similarly to that specified in Example 1. Test results are given in Table 1 below.
EXAMPLE 5 A catalyst is produced in the same way as described in Example 1, the molar ratio of calcium chloride to diammonium phosphate being 2.5:1. The reaction mixture obtained is treated with phosphoric acid until a pH-value is reduced to 5.0.
Testing of the catalyst produced is carried out in the same manner as shown in Example 1. Test results are given in Table 1 below.
EXAMPLE 6 A catalyst is produced in the same manner as described in Example 1. To prepare the reaction mixture, 1.78 1. of a solution containing calcium nitrate at 1 51 g/l is used instead of calcium chloride solution.
Interaction of the salts is carried out at a molar ratio of calcium nitrate to diammonium phosphate of 2.5:1, pH of the reaction mixture upon the addition of phosphoric acid being 5.75.
Testing of the catalyst is carred out in the same manner as specified in Example 1.
Test results are given in Table 1 below.
EXAMPLE 7 A catalyst is produced in the same way as described in Example 1. To prepare the reaction mixture, 1.85 1. of a solution containing calcium acetate at 139.04 g/l is used instead of calcium chloride solution.
Interaction of the salts is carried out at a molar ratio of calcium acetate to diammonium phosphate of 2.5:1, pH of the reaction mixture upon the addition of phosphoric acid being 5.75.
Testing of the catalyst is carried out as described in Example 1.
Test results are given in Table 1 below.
EXAMPLE 8 A catalyst is produced in the same way as described in Example 1. To prepare the reaction mixture, 1.59 1. of a solution containing disodic phosphate at 55.38 g/l is used instead of diammonium phosphate solution.
Interaction of the salts is carried out at a molar ratio of calcium chloride to disodic phosphate of 2.5:1, pH of the reaction mixture upon the addition of phosphoric acid being 5.75.
Testing of the catalyst is carried out in a similar way as described in Example 1.
Test results are given in Table 1 below.
EXAMPLE 9 A catalyst is produced in the same manner as described in Example 1. To prepare the reaction mixture, 1.59 1. of dipotassium phosphate solution at 67.86 g/l is used instead of diammonium phosphate solution.
Interaction of the salts is carred out at a molar ratio of calcium chloride to dipotassium phosphate of 2.5:1, pH of the reaction mixture upon the addition of phosphoric acid being 5.75.
Testing of the catalyst is carried out in the same way as described in Example 1.
Test results are given in Table 1 below.
EXAMPLE 10 A catalyst is prepared in the same manner as described in Example 1. Interaction of the salts is carried out at a molar ratio of calcium nitrate to diammonium phosphate of 1.5:1, pH of the reaction mixture upon the addition of phosphoric acid being 5.75.
Testing of the catalyst is carred out in the same way as described in Example 1.
EXAMPLE 11 A catalyst is prepared in the same way as described in Example 1. Interaction of the salts is carried out at a molar ratio of calcium nitrate to diammonium phosphate of 5.0:1, pH of the reaction mixture upon the addition of phosphoric acid being 5.75.
Testing of the catalyst is carried out as shown in Example 1.
Test results are given in Table 1 below.
In description of the present invention embodiments disclosed above, specific narrow terminology has been resorted to for the sake of clarity. It should be understood, however, that the present invention is in no way limited to the terms so selected and that each such term covers all equivalent elements operating in a similar manner and employed for solving similar problems.
Though the present invention has been described herein with reference to the preferred embodiments thereof, it will be understood that minor changes in carrying out the steps of the method for producing calcium phosphate catalyst may be made without departing from the spirit and scope of the invention, as will be readily understood by those skilled in the art.
All these alterations and changes will be considered to remain within the limits of the spirit and scope of the invention set forth in the claims.
TABLE 1 RESULTS OF TESTING THE CATALYST IN THE PROCESS OF DMD DECOMPOSITION Average operating temperature - 360 C Space velocity of the EMD-feeding - 1 h Delution DMD:H2O - 1:2 Catalyst of Example Characteristic No. 1 2 3 4 5 6 7 8 9 10 11 DMD conversion, % 96.3 96.1 96.6 91.2 96.9 96.5 96.1 95.9 96.0 96.3 91.5 Selectivity, molar % 86.3 85.4 85.1 84.6 85.8 85.4 85.3 85.6 85.7 85.2 84.3 Coke deposition, molar % 2.01 2.47 2.59 2.28 2.67 2.60 2.43 2.22 2.10 2.59 2.19

Claims (5)

1. A method for producing calcium phosphate catalyst comprising interacting a calcium salt and a phosphate in an aqueous-ammonia medium at a molar ratio of the calcium salt to phosphate of 1.5-5.0:1, treating the reaction mixture thus obtained with phosphoric acid until a pH-value of 5.0-7.0 is reached, followed by separating a precipitate from the reaction mixture, shaping the precipitate and its subsequent drying.
2. A method as claimed in Claim 1, wherein interaction of said calcium salt and phosphate is carried out at a molar ratio of 2.5:1, respectively.
3. A method as claimed in Claim 1 or 2, wherein said reaction mixture is treated with phosphoric acid until a pH-value of 5.5-6.0 is reached.
4. A method as claimed in Claims 1,2 or 3 substantially as hereinbefore described in any one of the Examples.
5. A catalyst whenever produced by any of the processes claimed in the preceding claims.
GB7925416A 1979-07-20 1979-07-20 Method for producing calcium phosphate catalyst Expired GB2053871B (en)

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GB2053871B GB2053871B (en) 1983-03-09

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2159510A (en) * 1984-05-25 1985-12-04 Vysoka Skola Chem Tech Process for the production of calcium hydrogen phosphate dihydrate and/or anhydrous calcium hydrogen phosphate
WO2021173738A1 (en) 2020-02-28 2021-09-02 The Procter & Gamble Company Method to remove chemical contaminants

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2159510A (en) * 1984-05-25 1985-12-04 Vysoka Skola Chem Tech Process for the production of calcium hydrogen phosphate dihydrate and/or anhydrous calcium hydrogen phosphate
WO2021173738A1 (en) 2020-02-28 2021-09-02 The Procter & Gamble Company Method to remove chemical contaminants
WO2021173739A1 (en) 2020-02-28 2021-09-02 The Procter & Gamble Company Method of using nanofiltration and reverse osmosis to remove chemical contaminants

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