DE3030409A1 - Catalyst for 1,3-dioxan decomposition to isoprene - contains calcium oxide, phosphorous pent:oxide, chlorine, boron oxide and water - Google Patents

Abstract

A catalyst comprises 48.5-53.5 wt.% CaO; 42.5-46.5% P205; 0.05-1.0 (pref. 0.02-0.3)% Cl; 0.005-3.0(pref. 0.02-0.3)% B203; and water as balance to 100%. A 1,3 dioxane is catalytically converted into isoprene using the above catalyst. The catalyst is generally useful for mfr. of isoprene from isobutylene and formaldehyde, and in alcohol dehydration reactions, esp. for decompsn. of 4,4 dimethyl-1,3 dioxane to isoprene. It provides higher activities at lower temps. than known catalysts, e.g. a 40% increase in 1,3 dioxane decomposition at 280 deg.C; higher selectivity by about 12 mole%, normally giving selectivity about 87-88%; and catalyst life up to 6 times higher than known catalysts.

Description

CATALYST FOR THE SPLITTER OF 1,3-DIOXANES

The invention relates to the production of catalysts e.g. in the production of isoprene from isobutylene and formaldehyde as well as in reactions the dehydration of alcohols find use, and more precisely one on a catalyst for the splitting of 1,3-dioxanes into isoprene, in particular 4,4-dimethyl-1,3-dioxane (also called DMD).

For now; Catalysts are known to produce calcium oxide in a close range from 54.2 to 56.3 weight percent, phosphorus pentoxide in an amount from 42.8 to 45.7 percent by mass and the remainder water contains up to 100 percent (see e.g. Kinetika i kataliz, B. 1, eft 2, 1960, 8. 247-256).

The catalysts, which have the specified composition, have a low activity in reactions of the 1,3-dioxane splitting, the a low volume - rate of raw material addition, which is 0.5 to 0.7 hours, as well as a high temperature of the catalytic splitting, approximately from 370 ° to 3900C, caused.

The activity of the catalysts depends on their acidity, the is determined by the number and strength of the active centers and by the depth of division the 1,3 - Diosane can be labeled under the same conditions.

The depth of splitting of the 1,3-dioxanes is determined by the ratio of the Amount of 1,3-dioxanes reacted, expressed in moles, to the amount of reacted 1,3-Dioxanes, expressed in jol, determined.

The selectivity of the catalysts mentioned is also not yet and is 68 to 75 mole percent.

The selectivity is expressed as the ratio of the amount of isoprene formed, Expressed in moles, defined as the amount of 1,3-dioxana converted, expressed in roles. The selectivity is given in percent.

The selectivity is due to the composition as well as the structure of the catalyst as well as through the Catalysis operating parameters conditional.

When the selectivity is increased, the amount of 1,3-dioxane raw material, those used to manufacture a unit of the finished product, e.g. a ton of isoprene, is necessary from. The insufficiently high selectivity of the catalyst is a problem high raw material consumption for isoprene production, the approx. 2.10 to 2.25kg 1,3-dioxanes per 1 kg of isoprene.

In the case of the above catalysts, there is also one increased coke deposition, which is 3.0 to 5.0 mole percent. The coke deposit will by the ratio of the amount of coke formed to the amount of converted 1,3-dioxane, both expressed in moles, determined. The coke deposit is given as a percentage. The increased coke deposition leads to a reduction in the selectivity of the 1,3-dioxane splitting process and increases the unproductive energy consumption when regenerating the catalyst by burning out the deposited coke by means of a steam-air mixture at the temperature from 4000 to 5000C.

There are also catalysts known that contain cadmium oxide in an amount of 12.d percent by mass, calcium oxide in an amount of 40.1 percent by mass, phosphorus pentoxide contained in an amount of 40.0 percent by mass and water up to 100 percent by mass (see, e.g. "Izvestija vysshikh uchebnykh zavedenij ". Khimija i @ tekhnicheskaja tekhnologija, B. 7, No. 5, pp. 801-805).

The catalysts with this composition do not have high activity and a relatively short keoensaauer, which is 300 hours.

The service life depends on the various parameters, including Composition and structure of the catalyst, its activity, operating temperature, hock deposit.

In addition, the catalysts of the type mentioned have a low selectivity which is 78 to 80 mole percent. The known catalysts mentioned above They also only have a low output, ranging from 0.20 to 0.25 t of isoprene per 1 m3 of catalyst per hour.

The performance of the catalytic converter depends on its activity and selectivity as well as the rate at which the raw material is added.

Despite the advantages of decardened catalysts, so far there is no industrial one Production process for 1,3-dioane splitting with these catalysts developed, since there is no catalyst that has the selectivity and stability, those for realizing the process on an industrial scale with high yield of the end product are sufficient.

The invention is based on the object by changing the composition of the catalyst for splitting 1,3-dioxanes to increase its activity Increase performance, selectivity and service life, as well as coke deposition in the 1,3-dioxane decomposition process.

The task is through a catalyst for the splitting of 1,3-dioxanes dissolved, which is composed of calcium oxide, phosphorus pentoxide, chlorine and water, and according to the invention also contains boron trioxide with the following ratio of the named components: (in Calcium oxide ................... 48.50 - 53.50 phosphorus pentoxide .............. 42.50 - 46.50 chlorine ......................... 0.05 - 1.00 boron trioxide ................. ... 0.005 - 3.000 water ........................ remainder A catalyst for splitting of 1,3-dioxanes with this composition has compared to the known Catalyst has a higher activity at low operating temperatures, which is what the increase in the depth of splitting of the 1,3-dioxanes at the temperature of 280 ° C The selectivity of the splitting of 1,3-dioxanes can be seen at approx. 40 percent with the proposed catalyst is at least 12 mole percent higher than with the aforementioned catalysts and is d7 to od mol percent.

The life of the catalyst for splitting 1,3-dioxanes the above composition is about six times higher than that of the known Catalysts.

It is desirable that the boron trioxide content in the catalyst for the splitting of 1,3-dioxanes O.C2 is up to 0.30 percent by mass.

The stated boron trioxide content at the above ratio of the components leaves the selectivity; of the analyzer for splitting 1,3-dioxanes increase, which means that the depth of division is practically constant within 100 operating hours remain.

It is recommended that the chlorine content in the inventive catalyst for the splitting of 1,3-dioxanes is 0.20 to 0.30 percent by mass.

The specified chlorine content enables coke to be deposited below 1 mole percent to reduce.

Calcium salt solutions, e.g. calcium chloride, are used as starting components and phosphoric acid salt solutions such as diammonium phosphate, dinate, rium phosphate et al., used. The solution of the phosthoric acid salt is before the interaction with the ammonia solution for pH adjustment is added to the solution of the calcium salt.

The solutions of the calcium and phosphoric acid salts are placed in a stirred tank poured gradually with continuous stirring of the suspension that forms. The interaction takes place at the molar ratio of the calcium and phosphoric acid salts from 1.5: 1. The interaction can also take place at the molar ratio of the starting components in the range from 1.5 to 5.0: 1, preferably from 2.5: 1. In this case it will the reaction mixture formed with the phosphoric acid solution to a pH of 5.0 treated to 7.0, preferably from 5.5 to 6.0.

The above ranges of the proportions of the salts of the salts of salts and phosphoric acid as well as the pH ensure the generation of the calcium phosphate catalyst the required structure and composition.

The precipitate formed is filtered or by any other method secreted from the calcium salt anion with distilled water washed free, granulated according to known processes and at a temperature of 1100 to 14000 dried, whereby the exhaust calcium phosphate is obtained, the Illan then brings it into a reactor0 The reactor consists of a quartz tube with a diameter of 20 to 26 mm. It is used in a slettro oven.

The introduction of boron into the starting calcium phosphate takes place at a thermal treatment at a temperature of 400 to 600 ° C with steam, in boric acid or a mixture of boric and phosphoric acid is added. The boric acid is in the water vapor in an amount of 0.01 to 0.8 percent by weight, preferably of 0.02 mass percent is added. If the thermal treatment of the catalyst in The presence of the mixture of boric and phosphoric acids is made Boric acid content in steam 0.001 to 0.02 percent by mass and the phosphoric acid content 0.0015 to 0.03 mass percent, preferably 0.002 mass percent and 0.003 mass percent for boric or phosphoric acid.

in the treatment, the molar ratio of doric and phosphoric acids is used in the range from 0.1 to 10: 1, preferably from 1: 1.

The treatment time is 2 to 50 hours, preferably 20 to 30 hours The thermal treatment can also be carried out with water vapor with the addition of Inert gas, especially nitrogen, argon, etc., can be made.

The water vapor is developed during the thermal Sehand-Volumens at a speed of 0.5 to 2.5 h, preferably from 1.0 to 2.0 h-1, fed.

In the manufacture of the calcium phosphate catalyst without treatment The thermal treatment of the reaction mixture with the phosphoric acid solution takes place preferably at a temperature of 400 ° C.

But if the storage for the production of the calcium phosphate catalyst a stage of treating the suspension with phosphoric acid to pH 5.0 to 7.0 includes, the thermal treatment is preferably carried out at one Temperature of 4500C.

The catalyst produced by this process consists of (in percent by mass): 46.5 to 53.50 calcium oxide, 42.50 or 46.50 phosphorus pentoxide, 0.05 to 1.00 chlorine, 0.005 to 3.000 boron trioxide, the remainder is made up of the water. It is preferable that the ratio of calcium oxide to phosphorus pentoxide in the range of 2.80 to 2.95 lying. The best results in terms of activity, selectivity and stability yields the catalyst, which contains 0.02 to 0.30 percent by mass of boron trioxide. Of the The degree of implementation of the DMD is around 90 percent and remains within 100 operating hours practically constant. The selectivity is 87.0 to 88.0 mole percent.

The best results for coke build-up are with chlorine levels from 0.20 to 0.30 percent by mass. The coke deposit is less than 1 percent.

Typical examples are given below that represent specific aspects Illustrate the present invention and its particularities and advantages express it most clearly.

example 1.

The starting calcium phosphate is at a temperature of 4000C within 24 hours of thermal treatment with steam with the addition of 0.001 percent by mass dorsic acid and exposed to 0.0015 mass percent phosphoric acid. That way The catalyst produced consists of (in weight percent): 48.50 halium oxide, 43.00 Shospnor pentoxide, 0.26 chlorine, 0.007 boron trioxide, the remainder; - content forms the water. The catalyst is used for the cleavage of 4,4-dimethyl-1,3-dioxane (DMD) in a steam atmosphere checked. The DMD cleavage occurs at an average temperature of 200C and atmospheric pressure within 100 hours. 24 cm3 of the catalyst are placed in a quartz tube with a diameter of 20 to 26 mm Reactor entered.

The reactor is placed in an electric furnace. DMD comes in a narrow of 24 cm3 per hour and water of 4d cm³ volume) enforced per hour, resulting in a DMD throughput rate of 1.0 h-1 and DMD dilution with Corresponds to water vapor in a ratio of 1: 2. The contact cycle, the Lasting 2 hours, a regeneration cycle follows, which involves burning out of the deposited coke.

The regeneration cycle takes place in a steam-air mixture at one temperature carried out by 4250C by pumping 48 cm3 of water and 16 800 cm3 calls. The catalyst is analyzed by means of gas-liquid chromatography. The deposited The amount of coke is determined according to known procedures.

The results of the catalyst test are shown in the table below 1 listed.

Example 2.

The starting calcium phosphate is at a temperature of 60,000 within 24 hours of thermal treatment with steam with the addition of 0.020 percent by mass Exposed to boric acid. The catalyst prepared in this way consists of (in Percent by mass): 53.50 calcium oxide, 46.06 phosphorus pentoxide, 0.25 chlorine, 0.271 boron trioxide, the remainder is made up of the water. The test is carried out as in example 1. The test results are listed in Table 1 below.

Example 3.

The starting calcium phosphate is as in Example 1 treated. The treatment temperature is 450 ° C. The boric acid content is 0.002 percent by mass, the content of phosphoric acid - 0.0030 percent by mass. The one made in this way The catalyst consists of (in percent by mass): 49.03 calcium oxide, 42.50 phosphorus pentoxide, 0.24 chlorine, 0.039 sort trioxide, the remainder is the water.

The test is carried out as in example 1. The test results are listed in Table 1 below.

Example 4.

The starting calcium phosphate is treated as in Example 1. the Treatment temperature is 475 ° C. The boric acid content is 0.006 percent by mass, the content of phosphoric acid - 0.0090 percent by mass. The one made in this way Catalyst consists of (in percent by volume): 51.63 calcium oxide, 46.50 phosphorus pentoxide, 0.22 chlorine, 0.150 boron trioxide, the remainder is made up by water.

The test is carried out as in example 1. The test-obserations are listed in Table 1 below.

Example 5.

The starting calcium phosphate is treated as in Example 2. the The temperature of the treatment is 500 ° C.

The catalyst prepared in this way consists of (in percent by mass): 52.30 calcium oxide, 45.10 phosphorus pentoxide, 0.05 chlorine, 0.232 boron trioxide, the remainder is made up of the water.

The test is carried out as in example 1. The test results are listed in Table 1 below.

Example 6.

en The starting calcium phosphate by chlorine ion / incompletely washed off is treated as in Example 3.

The catalyst produced in this way consists of (by mass percent): 51.31 calcium oxide, 44.61 phosphorus pentoxide, 1.00 chlorine, 0.054 boron trioxide, the remainder forms the water. The test is carried out as in example 1. The test results are listed in Table 1 below.

Example 7.

The starting calcium phosphate is treated as in Example 1. the Treatment temperature is 4500C.

The catalyst prepared in this way consists of (in percent by mass): 50.95 calcium oxide, 44.78 phosphorus pentoxide, 0.22 chlorine, O.OQ5 boron trioxide, the remainder forms the water. The test is carried out as in example 1. The test results are listed in Table 1 below.

example ö.

The starting calcium phosphate is treated as in Example 2. the Treatment temperature is 450 ° C. The boric acid content is 0.800 percent by mass.

The catalyst prepared in this way consists of (in percent by mass): 51.42 calcium oxide, 44.8 phosphorus pentoxide, 0.24 chlorine, 3,000 boron trioxide, the remainder forms the water.

The test is carried out as in example 1. The test results are listed in Table 1 below.

Example 9.

The starting calcium phosphate is treated as in Example 3. the The treatment temperature is 47500. The catalyst prepared in this way consists of (in percent by mass): 51.05 calcium oxide, 44.71 phosphorus pentoxide, 0.30 Chlorine, 0.040 boron trioxide, the remainder is made up of the water. The test is carried out as in Example 1. The test results are given in Table 1 below.

Example 10.

The starting calcium phosphate is treated as in Example 3. the Treatment temperature is 4500C. The boric acid content is 0.02 percent by mass, the phosphoric acid content - 0.03 percent by mass. That way The prepared catalyst consists of (in percent by mass): 51.00 calcium oxide, 45.14 Phosphorus pentoxide, 0.27 chlorine, 0.300 boron trioxide, the remainder is made up of water. The test is carried out as in example 1. The test results are in the following Table 1 listed.

Example 11.

The output calcium phosphate is treated as in Example 3. the Treatment duration is 30 hours. The catalyst prepared in this way consists of (in percent by mass): 49.53 calcium oxide, 43.23 phosphorus pentoxide, and 20 Chlorine, 0.045 boron trioxide, the remainder is the water. The test is carried out as in Example 1. The test results are given in Table 1 below.

Example 12.

The starting calcium phosphate is treated as in Example 3. the Treatment duration is 50 hours. The catalyst prepared in this way consists of (in teal percent): 50.12 calcium oxide, 43.90 phosphorus pentoxide, 0.18 Chlorine, 0.059 boron trioxide, the remainder is made up of the water. The test is carried out as in Example 1. The test results are given in Table 1 below.

Table results of the catalyst tests in the DMD cleavage Operating temperature: ... 280 ° C Space velocity of the DMD throughput: ... 1.0 h-1 DMD dilution with H2O: 1: 2 catalyst according to Examples 1 2 3 4 Details of cycle no 1 1 50 1 50 1 50 1 50 DMD breakdown depth,% 90.0 89.4 83.2 79.5 90.1 89.9 90.2 89.9 selectivity, mole% 87.2 87.6 87.5 87.9 87.6 88.0 87.6 88.0 coke deposit, Mole% 0.94 0.56 0.49 0.35 0.71 0.52 0.58 0.45 5 6 7 8 1 50 1 50 1 50 1 50 86.0 82.4 90.4 90.1 89.8 89.2 90.2 86.3 87.5 87.8 87.0 87.5 87.4 87.7 87.2 87.6 0.71 0.50 1.20 0.87 0.81 0.59 1.00 0.69 9 10 11 12 1 50 1 50 1 50 1 50 90.0 89.7 90.1 86.3 90.1 89.8 90.0 89.8 87.7 88.0 87.4 87.7 87.7 87.9 87.5 87.7 0.60 0.49 0.96 0.62 0.67 0.50 0.63 0.47

Claims (1)

CATALYST FOR THE DEVELOPMENT OF 1,3-DIOXANES P A T E N T A N S P R Ü C H E: 1. Catalyst for splitting 1,3-dioxanes, which is made from calcium oxide, Phosphorus pentoxide, chlorine and water is made up and there are no indications it is not indicated that there is trioxide in the following ratio of the components mentioned in percent by mass contains: calcium oxide ................... 48.5 to 53.5 phosphorus pentoxide ............ 42.5 to 46.5 chlorine ................... 0.05 to 1.0 boron trioxide ........... ... 0.005 to 3.0 water .................. residual content 2. catalyst according to claim 1, that it is boron trioxide in a quantity contains from 0.02 to 0.3 percent by mass. 3. Catalyst according to claim 1, d a d u r c h g e -K e n n z e i c h n e t that it contains chlorine in an amount of 0.2 to 0.3 mass percent.