DE1185169B - Process for the catalytic isomerization of straight-chain or branched 1,2-oxidoalkanes - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: C 07 c

German: 12 ο-7/03

Number: 1185 169

File number: S77677IVb / 12o

Filing date: January 23, 1962

Display day: January 14, 1965

The invention relates to a process for the catalytic isomerization of straight-chain or branched 1,2-oxidoalkanes into the corresponding carbonyl compounds, which is characterized in that the 1,2-oxidoalkanes are preferably passed in the presence of an inert gas over a catalyst consisting of at least one inorganic salt of the group ZnSO ₄ , Cr (SOJ ₃ , MnF ₂ , MnCl ₂ and MnBr ₂ optionally on a support, and that the reaction at temperatures between 150 and 450 ° C, preferably between 250 and 350 ° C, with residence times between 0.56 and 1.8 seconds and at atmospheric pressure or overpressure The diluent gas used is preferably recycled into the reaction after the carbonyl compounds have been separated off.

These salts specified above can be used individually or mixed with one another.

It is known that the 1,2-oxidoalkanes isomerize at temperatures between 150 and 450 ° C. in the presence suitable catalysts, for example, from ethylene oxide a single product, namely Acetaldehyde, while three products are obtained from propylene oxide, namely propionaldehyde, acetone and Allyl alcohol. The 1,2-oxides of the higher olefins also give several isomers. Further In addition to these substances, there is always both the hydration of the reaction oxide to form glycol in the presence of Water vapor as well as the formation of polymerization and condensation products of the reaction oxide or the substances formed are possible and sometimes even predominant. It goes without saying the expediency of using catalysts, which in the desired implementation are very selective.

There are some patents that use certain substances as catalysts for this reaction claim. For example, in German patents 618 972, 528 822 and 535 651 silica gel, Silicates, magnesium pyrophosphate, cerium sulfate and halides and oxyhalides of the alkaline earth metals and the sulfates or phosphates of the alkaline earth or earth metals while U.S. Patents 2,503,050.2,521 170.2 600 654,2 600 655 and 2,601,538 Mixtures of chromium, tungsten and iron oxides with and without the addition of cadmium chloride and oxide claim as catalysts for the implementation in question.

The tests carried out have shown that when using the catalysts provided according to the invention, far better conversions and greater yields than when using those in the process for the catalytic isomerization of straight-chain or branched ones
1,2-oxidoalkanes

Applicant:

Sicedison S. p. A., Milan (Italy)

Representative:

Dr.-Ing. R. Poschenrieder, patent attorney,
Munich 8, Lucile-Grahn-Str. 38

Named as inventor:

Paolo Ciattoni, Milan (Italy)

Claimed priority:

Italy January 27, 1961 (1463)

mentioned patents described catalysts are achievable.

US Pat. No. 2,601,538 describes the catalytic isomerization of propylene oxide to Propionaldehyde, whereby propylene oxide vapor is passed over a chromium oxide-tungsten oxide complex.

According to US Pat. No. 2,159,507. the Isomerization of alkylene oxides carried out with an alum as a catalyst.

To the large differences between the residence times in the process according to the invention and those which can be found in the examples of US Patents 601 538 and 2159 507, to be emphasized, Let us first be the calculation scheme for the conversion of the spatial velocity as in the U.S. patents cited, d. H. Grams of propylene oxide per hour times liter of the catalyst, in Contact (or dwell) time as defined in the description, i.e. H. Catalyst volume per volume of Gases that pass per second under test conditions (temperature and pressure) are shown.

409 768/291

It means

Q - hourly flow rate of the supplied alkylene oxide (g / h · 1 catalyst),

PM = molecular weight of the supplied alkylene oxide,

t - test temperature in ° C,
Vs = spatial velocity = liters of gas that pass through 1 1 of catalytic charge in one second (seconds " ¹ ),
1 Vs

If one knows Q, PM, t, then we get:
Q

.22 * -'- + ™ - 3600 PM '273

Vs (seconds- ¹ ):

Tc = contact time = -y, _ (seconds).

985 915 -

(0-2009); -22.4- "

3600.58 273

(0-2077); ³⁰⁵ 22.4-215 ^{+ 273}
3600.58 273

- = Tc. Vs

Using this calculation scheme for the ίο two examples in Table I (catalysts 0-2009 and 0-2077) with 100% conversion of the USA patent 2 601 538 results in:

= Vs = 0.055 seconds - ¹ J Tc = = 18.2 seconds.

0.055

= Vs = 0.06 seconds ^-1 ; Tc = —— ■ = 16.7 seconds.

0.06

The conversion for Examples I and II of US Pat. No. 2,159,507 gives the following results:

Example I: J ⁵⁰ . 22.4 x ²⁸ ° ^{+ 273} = Vs = 0.14 seconds ^-1 ; Tc = 7.15 seconds. 3600.58 273

940

175
Example II: ---—- -22.4

3600.58 273

73
- = Fj = 0,025Sekunden- ^l; Tc = 40 seconds.

These much longer contact or residence times than in the invention represent an important technical one Progress, which consists in the substantial reduction of the dwell time, which in particular is of great advantage if you have gases with a low content of alkylene oxide, such as mixtures of ethylene and ethylene oxide, such as those from the oxidation reactors of ethylene Silver catalyst leak. It should be noted that in Example I of U.S. Patent 2159507, although there, too, the residence time is far longer than in the invention, a conversion of only 85 7o is reached.

The invention is illustrated by means of the following examples. For the production of the catalyst, no protection is sought at this point.

Manufacture of the catalysts

I. ZnSO ₄

This catalyst used in Example 1 was tableted by a slight moistening of dehydrated zinc sulfate, and heated for several hours at 35O ⁰ C.

II. Cr ₁ (SO ₄ ),

This catalyst used in Examples 2 to 4 was performed by careful dehydration of Cr ₈ (SOI) ₃ • «H ₂ O while gradually increasing the temperature of 70 ⁰ C to about 300 ⁰ C. The product obtained was finely ground and ^{heated to 450 °} C. for a few hours until the water had almost completely disappeared. Then, it was mixed with a catalyst carrier, pelletized, and heated for several hours at 350 ⁰ C.

III. MnF ₂

This catalyst used in Example 5 was obtained by precipitating MnF ₂ from concentrated MnSO ₄ and NH ₄ F solutions and concentrating the solution by evaporation in order to achieve a more complete precipitation of the manganese fluoride, which is quite soluble in water.

The precipitate was then washed with a water-alcohol solution, dried, mixed with kieselguhr and made into tablets. Before use, the tablets were kept at 250 ^° C. for a few hours.

IV. MnCl ₂

This catalyst used in Examples 6 and 7 was obtained by allowing an MnCl ₂ solution to be absorbed by kieselguhr with constant stirring. The resulting mass was dried, ground and processed into tablets, which were kept at 300 ^° C. for a few hours before use.

V. MnBr ₂

The catalyst used in Example 8 was obtained starting from a concentrated MnSO ₄ solution, from which the manganese sulfide was _{precipitated by saturation with H 2} S and the gradual addition of ammonia solution. The precipitate was then _{washed with an (NH 4} ) ₂ S solution and then with _{water saturated with H 2} S until the SO ₄ ion had completely disappeared and, after its suspension in a little water, was washed cold with an HBr solution until it was completely dissolved treated. _{The H 2} S was removed from the resulting solution by continued boiling. During this treatment, the solution became cloudy due to the excretion of traces of colloidal sulfur, which were carefully removed by filtering through activated carbon. From the filtrate, the manganese was deposited by evaporation and then at 25O ⁰ C dried.

After intimate mixing with kieselguhr, the MnBr ₂ powder was processed into tablets which were kept ^{at 250 ° C. for a few hours before use.}

Carrying out the experiments

The experiments according to the examples given were carried out using both steam as well as nitrogen as a diluent of the 1,2-oxidoalkanes. In the trials of the first type is the proportion of 1,2-oxidoalkanes in Expressed weight percent, and the feed was made, by introducing an aqueous epoxy solution into an evaporator and the evaporated mixture was passed into the catalyst zone. In the experiments of the second type, the 1,2-oxidoalkane portion was used (which is always given in parts by volume in the examples cited) dadurqh regulated that the Temperature of the liquid oxide in a wash bottle was set, through which the nitrogen flow was pearled and saturated. Tests were also carried out without gaseous diluents, however, it has been shown that it can be used for better control of heat generation during the implementation it is preferable to use low oxide mixtures.

The gaseous mixture containing the 1,2-oxidoalkane in the desired proportion was passed into a tubular reaction vessel made of quartz about 100 cm long and 20 mm inside diameter, in the middle area of which 150 cm ^{3 of} the catalyst were arranged. The area in front of the catalyst was filled with quartz grains and served to preheat the incoming gas mixture.

The reaction vessel was placed in a controllable tubular electric furnace. The temperature measurement in the catalyst zone was carried out by moving an on-axis thermocouple centered with respect to the reaction vessel. The reaction products were extracted from the escaping gases by passing the gases through water have been washed; the nitrogen was returned to the cycle.

The products were determined by (chemical and chromatographic) analysis of the distilled fractions, while the 1,2-oxidoalkane introduced was determined by weighing. Some of the numerous tests carried out are given as examples in the following table. The term contact time refers to the volume ratio of the catalyst to the gases or Vapors that sweep over him per second, understood, with the gases as the ideal gas among the Experimental conditions are calculated.

catalyst Admitted Mixture C. Time
: n U position Yields based on the
supplied 1,2-oxidoalkane (Vo theory) Glycol Ketone • 53 loalka: Contact
second itur, ° I, ige 6.4 1
3 ZnSO ₄ 100 ° / ₀ ig share S. 0.56 Medium
Temp 100 unsaturated
Fabrics Cr ₂ (SOJ ₃ 67 ° / _o ig Inventory 3.5 350 aldehyde 4th 0 1 on diatomaceous earth Ethylene oxide water vapor 1.74 95 82 2 Cr ₂ (SOJ ₃ 67% ig 2.6 250 - 0 on diatomaceous earth Ethylene oxide N ₂ 1.70 98 86.7 3 Cr ₂ (SOJ ₃ 67 per cent 2.7 270 - 0 0.4 on diatomaceous earth Ethylene oxide N ₂ 1.80 100 91 4th MnF ₂ 42% 4.6 250 - 0 on diatomaceous earth Propylene oxide N ₂ 1.29 "93 92 5 MnCl ₂ 50% 2.8 353 - 0 on diatomaceous earth Ethylene oxide N ₂ 1.35 95 92 6th MnCl ₂ 50 ° / ₀ ig 2.7 301 ■ —- 0 on diatomaceous earth Ethylene oxide N ₂ 1.31 98 80 7th MnBr ₂ 63 ° / ig 2.8 351 - 0 on diatomaceous earth Ethylene oxide N ₂ 1.39 99 85.0 8th 2.7 300 - Ethylene oxide N ₂ 89.2

Claims (2)

Patent claims: 1. A process for the catalytic isomerization of straight-chain or branched 1,2-oxidoalkanes into the corresponding carbonyl compounds, characterized in that the 1,2-oxidoalkanes are preferably passed in the presence of an inert gas over a catalyst which consists of at least one inorganic salt of the group ZnSO _4, Cr (SOJ _3, MnF _2, MnCl ₂ and MnBr _2, optionally on a support, and in that the reaction at temperatures between 150 and 450 ⁰ C, preferably between 250 and 350 ° C, with residence times between 0, 56 to 1.8 seconds and at atmospheric pressure or overpressure. 2. The method according to claim 1, characterized in that that the diluent gas is recycled into the reaction after the carbonyl compounds have been separated off. Documents considered: German Auslegeschrift No. 1 035 635; German Patent No. 528 822; U.S. Patent Nos. 2,601,538, 2,159,507; Houben - Weyl, Methods of Inorganic Chemistry, 7/1, 1954, p. 238. 409 768/391 1.65 © Bundesdruckerei Berlin