GB2080134A - Catalysts for condensation, dehydration and decomposition reactions - Google Patents
Catalysts for condensation, dehydration and decomposition reactions Download PDFInfo
- Publication number
- GB2080134A GB2080134A GB8023575A GB8023575A GB2080134A GB 2080134 A GB2080134 A GB 2080134A GB 8023575 A GB8023575 A GB 8023575A GB 8023575 A GB8023575 A GB 8023575A GB 2080134 A GB2080134 A GB 2080134A
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- Prior art keywords
- catalyst
- chlorine
- water
- phosphorus pentoxide
- calcium
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- 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
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- 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
- C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
- C07C2523/02—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the alkali- or alkaline earth metals or beryllium
-
- 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
- C07C2527/06—Halogens; Compounds thereof
-
- 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
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Catalysts (AREA)
Abstract
A catalyst eg. for decomposition of 1, 3-dioxanes comprising calcium oxide, phosphorus pentoxide, chlorine, water end boron oxide with the following amounts of the components as expressed in weight percent: calcium oxide 48.5 to 53.5 phosphorus pentoxide 42.5 to 46.5 chlorine 0.05 to 1.0 boron oxide 0.005 to 3.0 the balance being water ,
Description
SPECIFICATION
Catalyst
The present invention relates to catalysts, especially catalysts that can be used, for example, in the manufacture of isoprene from isobutylene and formaldehyde, as well as in alcohol dehydration reactions and more especially in the decomposition of 1,3-dioxanes, in particular, in the decomposition of 4,4-dimethyl-l ,3-dioxane (hereinafter referred to as DMD) to give isoprene.
The present invention provides a catalyst for use for instance in the decomposition of 1,3dioxanes, the catalyst comprising calcium oxide, phosphorus pentoxide, chlorine, and water, and which according to the invention further comprises boron oxide. The ratio of the components expressed in weight percent is as follows: calcium oxide 48.50 to 53.50 phosphorus pentoxide 42.50 to 46.50 chlorine 0.05 to 1.00 boron oxide 0.005 to 3.000 water the balance to 100
The catalysts of the present composition typically show for decomposition of 1,3-dioxanes a high activity at low operating temperatures as compared with the known prior art catalysts, as evidenced by an approximately 40% increase often observed in the degree of 1,3-dioxane decomposition at a temperature of 280 C. The selectivity for the 1,3-dioxane decomposition using the present catalyst is often higher by at least 1 2 mole % when compared with the known catalysts and normally lies within the limits of from 87 to 88 mole %. The catalyst life is up to approximately six times or more that of the known catalysts.
It is advisable that the catalyst of the invention for decomposition of 1,3-dioxanes should comprise 0.02 to 0.3 weight percent of boron oxide. The boron oxide allows improved stability of the catalyst, thus resulting in a practically constant degree of decomposition during 100 operating hours.
It is also advisable that the chlorine content of the catalyst be 0.20 to 0.30 weight percent.
The specified content of chlorine allows coke deposition frequently to be reduced down to 1 mole % or below.
Suitable starting reactants for preparing the present catalysts are solutions of calcium salts, eg. calcium chloride, and phosphoric acid salts, eg. diammonium phosphate, disodium phosphate, etc. A suitable amount of aqueous ammonia is then added to the phosphate solution prior to reacting it with the calcium salt solution to control the pH of the medium.
In a peferred preparative procedure, a solution of a calcium salt and of a phosphate are gradually poured into a vessel fitted with a stirrer, and the slurry continuously being formed is stirred. The reaction can be carried out with the calcium salt and phosphoric acid salt taken in the molar ratio of 1.5:1. However the reaction is readily realizable when the starting reactants are in a molar ratio anywhere within the range of 1.5:1 to 5.0:1. In this case, the reaction mixture is treated with a phosphoric acid solution to pH of from 5.0 to 7.0 and preferably of 5.5 to 6.0. These ranges for the ratio of calcium salt to phosphoric acid salt and for the pH value of the reaction mixture provide for the production of a calcium phosphate catalyst with the desired structure and composition.
The resulting precipitate can be separated by filtration or any other conventional technique, washed with distilled water to remove calcium salt anions, shaped into granules by a conventional technique, and dried at a temperature of 110 to 140"C, thus obtaining raw calcium phosphate that is then loaded into a reactor.
The reactor is preferably a quartz tube of 20 to 26 mm in diameter, placed into an electrically heated furnace.
Boron is introduced into the raw calcium phosphate in the course of thermal treatment at 400 to 600"C using steam mixed with either boric acid or a mixture of boric and phosphoric acids.
Boric acid is normally added to steam in an amount of 0.01 to 0.8 weight percent, preferably of 0.02 weight percent. In the case where thermal treatment of the catalyst is accomplished in the presence of the mixture of boric and phosphoric acids, the content of the boric acid in the steam is normally 0.001 to 0.02 weight percent and the phosphoric acid content is normally 0.0015 to 0.03 weight percent while the preferable contents are 0.002 weight percent for boric acid and 0.003 weight percent for phosphoric acid.
In the course of the treatment the molar ratio of boric acid and phosphoric acid is usually maintained in the range of 0.1:1 to 10:1, preferably.
The duration of the treatment can be 2 to 50 hours, preferably 20 to 30 hours.
The thermal treatment can be also performed with steam mixed with air on an inert gas such as nitrogen, argon, etc.
In the course of the thermal treatment, steam is preferably supplied at a space velocity of 0.5 to 2.5 h-1 more preferably 1.0 to 2.0 h-'.
If the calcium phosphate catalyst is produced without any treatment of the reaction mixture by a phosphoric acid solution, thermal treatment is preferably performed at a temperature of 400on.
In the case where the process to prepare the calcium phosphate catalyst includes the stage of the slurry treatment by phosphoric acid at pH of from 5.0 to 7.0, thermal treatment is preferably carried out at a temperature of 450"C.
The catalyst thus obtained comprises, in accordance with the invention, in % by weight: 48.50 to 53.50 of calcium oxide, 42.50 to 46.50 of phosphorus pentoxide, 0.05 to 1.00 of chlorine, 0.005 to 3.000 of boron oxide, the balance being water. It is preferable that the calcium oxide: phosphorus pentoxide molar ratio be at a level of 2.80 to 2.95.
As to the activity, selectivity and stability, the best DMD conversion results are provided by a catalyst comprising 0.02 to 0.30 weight percent of boron oxide. The DMD conversion is typically at a level of 90% and usually remains practically constant during 100 operating hours, while selectivity is up to 87.0 to 88.0 mole %. As to the coke deposition, the best results are achieved with a chlorine content of 0.20 to 0.30 mass percent. The coke deposition is often at a level not exceeding 1 mole %.
The invention will be further described with reference to the following illustrative Examples.
Example 1
The initial calcium phosphate was treated with steam containing 0.001 mass percent of boric acid and 0.0015 mass percent of phosphoric acid added thereto, at a temperature of 400"C for 24 hours. The catalyst thus produced the following comprised components expressed in mass percent: calcium oxide, 48,50; phosphorus pentoxide, 43.00; chlorine 0.26 boron oxide, 0.007; the balance being water. The catalyst was tested in a DMD decomposition reaction in a steam atmosphere. The DMD decomposition reaction was carried out at an average temperature of 280"C and the atmospheric pressure for 100 h. 24 cm3 of the catalyst were loaded into a reactor which was a quartz tube 20 to 26 mm in diameter. The reactor was placed into an electric furnace.DMD is fed in at a rate of 24 cm3 per hour, while water is fed in at a rate of 48 cm3 per hour, which gave space velocity of DMD feed equal to 1.0 h-1 and a DMD-to-steam dilution ratio of 1:2. The contact cycle of 2 hours duration was followed by a regeneration cycle involving burning-out of the coke deposited. The regeneration cycle was carried out using a steam-air mixture at a temperature of 425"C, supplying 48 cm3 of water and 16,800 cm3 of air.
The catalyst was analyzed using the gas-liquid chromatography technique. The amount of coke deposited was determined by a conventional method. The test results are given in Table 1.
Example 2
The starting calcium phosphate was treated with steam, containing 0.020 mass percent of boric acid at a temperature of 600"C for 24 hours. The catalyst thus produced was composed of the following components expressed in mass percent: calcium oxide, 53.50; phosphorus pentoxide, 46.06; chlorine, 0.25; boron oxide, 0.271; the balance being water.
The catalyst was test run as described in Example 1. The test results are given in Table 1.
Example 3
The starting calcium phosphate was treated essentially as described in Example 1. The treatment temperature was 450"C. The concentration of boric acid was 0.002 mass percent, that of phosphoric acid, 0.0030 mass percent. The catalyst thus produced was composed of the following components expressed in mass percent: calcium oxide, 49.03; phosphorus pentoxide, 45.50; chlorine, 0.24; boron oxide, 0.039; the balance being water.
The catalyst was test run as described in Example 1. The test results are given hereinbelow in
Table 1.
Example 4
The starting calcium phosphate was treated essentially as described in Example 1. The treatment temperature was 475on. The concentration of boric acid was 0.006 mass percent, that of phosphoric acid, 0.0090 mass percent. The catalyst thus produced was composed of the following components expressed in mass percent: calcium oxide, 51.63; phosphorus pentoxide, 46.50; chlorine, 0.22; boron oxide, 0.1 50; the balance being water.
The catalyst was test run as described in Example 1. The test results are given in Table 1.
Example 5
The starting calcium phosphate was treated essentially as described in Example 2. The treatment temperature was 500"C.
The catalyst thus produced was composed of the following components expressed in mass percent; calcium oxide, 52.30; phosphorus pentoxide, 45.10; chlorine, 0.05; boron oxide, 0,232; the balance being water.
The catalyst was test run as described in Example 1. The test results are given in Table 1.
Example 6
The starting calcium phosphate washed incompletely free of chlorine ions was treated essentially as described in Example 3. The catalyst thus produced was composed of the following components expressed in mass percent: calcium oxide, 51.31: phosphorus pentoxide, 44.61; chlorine, 1.00; boron oxide, 0.054; the balance being water. The catalyst was test run as described in Example 1. The test results are given in Table 1.
Example 7
The starting calcium phosphate was treated essentially as described in Example 1. The treatment temperature was 450"C.
The catalyst thus produced was composed of the following components expressed in mass percent: calcium oxide 50.95;phosphorus pentoxide, 44.78; chlorine, 0.22; boron oxide, 0.005; the balance being water. The catalyst was test run as described in Example 1. The test results are given in Table 1.
Example 8
The starting calcium phosphate was treated essentially as described in Example 2. The treatment temperature was 450"C. The concentration of boric acid was 0.800 mass percent.
The catalyst thus produced was composed of the following components expressed in percent by mass: calcium oxide, 51.42; phosphorus pentoxide, 44.88; chlorine, 0.24; boron oxide, 3,000; the balance being water.
The catalyst was test run as described in Example 1. The test results are given in Table 1.
Example 9
The starting calcium phosphate was treated essentially as described in Example 3. The treatment temperature was 475"C. The catalyst thus produced was composed of the following components expressed in mass percent: calcium oxide, 51.05; phosphorus pentoxide, 44.71; chlorine, 0.30; boron oxide, 0.04; the balance being water. The catalyst was test run as described in Example 1. The test results are given in Table 1.
Example 10
The starting calcium phosphate was treated essentially as described in Example 3. The treatment temperature was 450"C. The concentration of boric acid was 0.02 mass percent, that of phosphoric acid was 0.03 mass percent. The catalyst thus produced was composed of the following components expressed in mass percent: calcium oxide, 51.00; phosphorus pentoxide, 45.14; of chlorine, 0.27; boron oxide, 0.300; the balance being water. The catalyst was test run as described in Example 1. The test results are given in Table 1.
Example 11
The starting calcium phosphate was treated in the same manner as described in Example 3.
The treatment duration was 30 hours. The catalyst thus produced was composed of the following components expressed in mass percent: calcium oxide, 49.53; phosphorus pentoxide, 43.23; chlorine, 0.20; boron oxide, 0.045; the balance being water. The catalyst was test run as described in Example 1. The test results are given in Table 1.
Example 12
The starting calcium phosphate was treated in the same manner as described in Example 3.
The treatment duration was 50 hours. The catalyst thus produced was composed of the following components expressed in mass percent: calcium oxide, calcium oxide, 50.12; phosphorus pentoxide, 43.90; chlorine, 0.18: boron oxide, 0.059; the balance being water.
The catalyst was test run as described in Example 1. The test results are given in Table 1. Table 1
Results of catalyst testing in DMD composition
Operating temperature: 280 C
Space velocity of DMD feed: @ h-1 DMD-to-H2O dilution ratio: 1:2
Catalyst @s per Example Nos. 1 2 3 4 5 6 7 8 9 10 11 12
Characteristics
Cycle Nos. 1 50 1 50 1 50 1 50 1 50 1 50 1 50 1 50 1 50 1 50 1 50 1 50
DMD
Conversion 90.0 89.4 83.2 79.5 90.1 89.9 90.2 89.9 86.0 82.4 90.4 90.1 89.8 89.2 90.2 86.3 90.0 89.7 90.1 86.3 90.1 89.8 90.0 89.8 level, %
Selectivity, 87.2 87.6 87.5 87.9 87.6 88.0 87.6 88.0 87.5 87.8 87.0 87.5 87.4 87.7 87.2 87.6 87.7 88.0 87.4 87.7 87.7 87.9 87.5 87.7 mole % @oke deposition 0.94 0.56 0.49 0.35 0.71 0.52 0.58 0.45 0.71 0.50 1.20 0.87 0.81 0.59 1.00 0.69 0.60 0.49 0.96 0.62 0.67 0.50 0.63 0.47 mole% Although the present invention has been described herein with reference to the preferred typical embodiments thereof, it will be apparent to those skilled in the art that there may be modifications made in the preparation of the catalyst.
Claims (5)
1. A catalyst comprising calcium oxide, phosphorus pentoxide, chlorine, boron oxide and water in the following amounts as expressed in weight percent: calcium oxide 48.5 to 53.5 phosphorus pentoxide 42.5 to 46.5 chlorine 0.05 to 1.0 boron oxide 0.005 to 3.0 water the balance to 100
2. A catalyst as defined in Claim 1, which comprises 0.02 to 0.3 weight percent of boron oxide.
3. A catalyst as defined in Claim 1, which comprises 0.2 to 0.3 weight percent of chlorine.
4. A catalyst substantially as hereinbefore described in the Examples.
5. A method for catalytic conversion of a 1,3-dioxane into isoprene wherein the catalyst is as defined in any preceding claim.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8023575A GB2080134B (en) | 1980-07-18 | 1980-07-18 | Catalysts for condensation dehydration and decomposition reactions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8023575A GB2080134B (en) | 1980-07-18 | 1980-07-18 | Catalysts for condensation dehydration and decomposition reactions |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2080134A true GB2080134A (en) | 1982-02-03 |
| GB2080134B GB2080134B (en) | 1984-03-28 |
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ID=10514875
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8023575A Expired GB2080134B (en) | 1980-07-18 | 1980-07-18 | Catalysts for condensation dehydration and decomposition reactions |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2080134B (en) |
-
1980
- 1980-07-18 GB GB8023575A patent/GB2080134B/en not_active Expired
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| Publication number | Publication date |
|---|---|
| GB2080134B (en) | 1984-03-28 |
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| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |