DE1156235B - Process for the polymerization of acetaldehyde - Google Patents

Description

ESTJSRNAT. KL. C 08 g

GERMAN

PATENT OFFICE

F 30633 IVd / 39 c

REGISTRATION DATE: FEB 26TH RU AR 1960

NOTICE THE REGISTRATION AND ISSUE OF THE EDITORIAL: OCTOBER 24, 1963

The polymerization of acetaldehyde in the presence of solid contacts is already known.

Furthermore, it has already been proposed to use acetaldehyde by a polymerization process in bulk in the presence of at least one inorganic and / or organic solid contact, which by at least one organic or inorganic acid, a Lewis acid or a Lewis acid in the form of known complex compounds or salt-like compounds, in amounts of 0.00005 to 0.1 ° / ₀ , based on the weight of the solid contact, is activated, at low temperatures of -30 to -120 ⁰ C to linear, high molecular weight polyacetaldehyde of the general formula

15 CH ₃

procedure
for the polymerization of acetaldehyde

Applicant:

Farbwerke Hoechst Aktiengesellschaft

formerly Master Lucius & Brüning,

Frankfurt / M., Brüningstr. 45

Dr. Klaus Weissermel,
Frankfurt / M.-Unterliederbach,
has been named as the inventor

- C — O-

to polymerize.

It has now been found that acetaldehyde polymers can be contacted in the presence of at least one organic and / or inorganic solid, which by at least one organic or inorganic acid, a Lewis acid or a Lewis acid in the form of known complex compounds or salt-like compounds, in amounts of 0.00005 to 0.1 ^o / o> based on the weight of the solid contact, activated, can be produced at temperatures of -30 to -120 ° C by the polymerization in the presence of saturated aliphatic, cycloaliphatic and / or araliphatic hydrocarbons, which in no interaction with the catalyst system and the monomer occur.

In the method according to the invention, the solid contact with one or more is first Load hydrocarbons by overlaying and then acetaldehyde in the temperature range mentioned introduced into the solid contact solvent dispersion and polymerized. The used aliphatic and cycloaliphatic !! Hydrocarbons are said to be advantageous with the acetaldehyde Form a two-phase system in the temperature range mentioned above and to Contact with solids will develop a lower adsorption force than acetaldehyde. When using of araliphatic hydrocarbons is advantageously worked so that the acetaldehyde dissolves at the temperatures given above in the solvent and the solvent a Has less or at most the same adsorptive force for contact with solids as acetaldehyde.

A major advantage of acetaldehyde polymerization to linear, high molecular weight polyacetaldehyde in the presence of a cationically active solid contact or in the presence of a cationic one effective solid contact mixture in the presence of indifferent aliphatic, cycloaliphatic and / or araliphatic hydrocarbons is based on the fact that the control of the polymerization process is simple and, by means of the measures outlined, premature deactivation of the solid contact surface is largely suppressed by polymer coverage.

Furthermore, the acetaldehyde polymerization by the process according to the invention can be carried out in the usual way Polymerization vessels are carried out, and finally the discharge of the polymer dispersion, which forms in the course of the polymerization is easier than discharging a polymer in bulk.

Suitable indifferent hydrocarbons with monomeric! Acetaldehyde form a two-phase system under the polymerization conditions in which the lower phase consists of acetaldehyde, are aliphatic and cycloaliphatic hydrocarbons, which have a fixed point which is below the temperature selected for the polymerization became.

Examples include: propane, butane, pentane, Hexane, heptane etc., cyclopropane, cyclobutane, cyclopentane, cyclohexene etc.

309 729/325

3 4

Suitable hydrocarbons which are activated with the mono amounts of 0.00005 to 0.1% based on the meric acetaldehyde below the polymerization weight of the solid contact. Particularly conditions are completely miscible with one another and effective are inorganic solid contacts, in addition to the solid contact an at most equal, for example, silica gel or aluminum oxide, in addition have great adsorptive power such as acetaldehyde, 5 activated with boron trifluoride. These inorganic solids are araliphatic hydrocarbons, such as toluene, substance contacts or inorganic solids contact-ethylbenzene, propylbenzene etc. mixtures can be particularly advantageous in combination with polyoxymethylenes, preferably a middle group compared to acetaldehyde at low levels after a polymerization process in bulk temperature has the following consequences for the polymers of trioxane that are used. Polymerization: The amount of cationically activated solid - If gaseous or liquid acetaldehyde contact is passed, or cationically activated solid into a polymerization medium, which consists of a cationic contact mixture, depends on the particular activated solid contact and an aliphatic activity and surface properties of the single or cycloaliphatic hydrocarbon or hydrocarbon. a 15 set inorganic and / or organic con-hydrocarbon mixture, a clock observes. It is within wide limits, for example in one in the course of the polymerization, the vorteilhafter- weight ratio of 1: 1 to 1: 100 solid contact, in a range -50 to -90 ⁰ C transit to acetaldehyde variable.

is performed, a demixing of the two liquid acetaldehyde required for the polymerization Phases, and that at the solid contact only loosely 20 is under by careful, fractional distillation

adsorbed aliphatic or cycloaliphatic carbon- exclusion of air and moisture shown in pure form

hydrogen is displaced by the acetaldehyde, and the polymerization mixture is gaseous or liquid,

and this begins to polymerize. optionally dissolved in the same solvent,

Since the slowly forming polyacetaldehyde in which the polymerization is to be carried out, Aliphatic hydrocarbons largely un-added.

is soluble, is obtained after the end of the polymerization. The polymerization takes place at low temperatures

a dispersion, which consists of the solid contact, which is in the range from about -120 to about -30 ° C, advantageous

Polymer and the solvent. adhesively in the range of -50 to -90 ° C.

If you pass gaseous or liquid acetaldehyde for processing, the mostly sponge-like in a polymerization medium which is dissolved from a cationic 3 ° polymer in acetone, ether or benzene, from

activated solid contact and z. B. freed from an aralipha solid contact by filtration and through

table hydrocarbon or from an aralipha water, optionally after the addition of stabilizers

table hydrocarbon mixture, a, such as / 5-naphthylamine, precipitated and dried. It

the polymerization also begins, although none is a rubbery, white polymer composition

Separation of the two liquid phases occurs. The 35 represents.

Polymerization proceeds in the presence of aralipha- The reduced viscosity, measured in a 0.1-

table hydrocarbons, for example in weight percent butanone solution at 25 ° C

Essence of toluene, but slower than per se, depending on the choice of polymerization conditions

Essence of aliphatic hydrocarbons. between 1 and 10. For the according to the invention

This is probably the polymer represented under this polymerization process

conditions characterize the polymerization rate by the UR spectrum given in Example 1

the interaction of adsorption and desorption ristically.

largely influenced by contact with solids. Since the acetaldehyde polymers, especially the sta-toluene in contact with the solid, are likely to be more solidly bilized acetaldehyde polymers, are bound to be used as the above-mentioned aliphatic or transparent films, sheets and molded cycloaliphatic hydrocarbons, the bodies with valuable properties are suitable for displacement reaction of solids laden with toluene for the polymerization substance contacts described below by acetaldehyde only slowly. Experiments were made with freshly distilled acetaldehyde. All polymerization attempts were carried out under substance polymer dispersions which consist of high-molar largely exclusion of air and moisture, and molecular polyacetaldehyde. The silica gel used in the experiments had The amount of hydrocarbons in a grain diameter of 0.2 to 0.5 mm and became the usual limits of dispersion polymerization. Dried at 480 ^° C. for 24 hours. It should advantageously be equal to or greater than the amount of acetaldehyde used as organic solid contact. All the indifferent polyoxymethylene mentioned was made by polymerizing the th hydrocarbons must be free from Verun Trioxane in bulk in the presence of complex compounds that disrupt or fertilize the polymerization process or make salt-like compounds uncontrollable by Lewis. For example, acids are produced. The polymerization block was called disruptive impurities: water, alcohol, ground, sieved and dried in vacuo for 24 hours, acids, amines, ethers, etc. Polymer particles were used

The polymerization of acetaldehyde after having a grain diameter of 0.8 to 1.6 mm. The method according to the invention takes place in the presence of the activation of the solid contact mixture with of at least one organic and / or inorganic boron trifluoride was carried out so that a mixture of stick niches Solid contact through at least one 65 substance and boron trifluoride via the solid contact under organic or inorganic acid, a Lewis acid stirring and moisture exclusion was passed, or a Lewis acid in the form of a known complex. The hydrocarbons used were high compounds or salt-like compounds, in cleaned and well dried.

example 1

A mixture of 10 parts by weight of silica gel and 20 parts by weight of polyacetal, activated with 0.0009 parts by weight Boron trifluoride is covered with a layer of 30 parts by weight of pentane and cooled down to -70 ° C. In the course of 7 hours, 56 parts by weight of gaseous acetaldehyde are then reduced under reduced pressure introduced into the hydrocarbon contact mixture.

After just a few hours, polyacetaldehyde is formed on the contact surface. After 40 hours the approach is processed. For this purpose, the pentane is filtered off or suctioned off, the polymer in acetone dissolved, freed from solid contact by filtration and, after adding 1 percent by weight of ß-naphthylamine, based on the acetone solution, precipitated with water. The polymer falls as a crumbly one The mass is washed several times with water and dried in vacuo at room temperature. Of the Conversion is 72 percent by weight.

The reduced viscosity of the polymer, determined in a 0.1% strength butanone solution at 25 ° C., is 3.95.

The UR spectrum was recorded to characterize the polymer (see figure). For this unstabilized polymer is drawn from a carbon tetrachloride solution onto a rock salt window.

Example 2

A mixture of 8 parts by weight of silica gel and 24 parts by weight of polyacetal, activated with 0.001 part by weight of boron trifluoride, is covered with 35 parts by weight of absolute, pure pentane and cooled the mixture to -75 ⁰ C. 58 parts by weight of liquid acetaldehyde are added in the course of 5 hours. The polymerization apparatus is under reduced pressure while the monomer is being added. Again, the polymer precipitates on the contact surface. The batch is worked up as described in Example 1 after 12 hours. The conversion is 61 percent by weight.

r \ _r eä, 3.32, measured in a 0.1% butanone solution at 25 ° C.

Example 3

45

A mixture of 10 parts by weight of silica gel and 25 parts by weight of polyacetal, activated with 0.001 part by weight Boron trifluoride is covered with 40 parts by weight of toluene and the batch is cooled to -65.degree. In the course of 7 hours, 60 parts by weight of gaseous acetaldehyde are added to the toluene contact dispersion initiated. When the addition of the monomer is complete, the acetaldehyde is only partially polymerized. The batch is therefore held at -65 ° C. for a further 50 hours and then worked up as usual. The conversion is 63%.

y \ reä, 4.04, measured in a 0.1% butanone solution at 25 ° C.

Example 4

OO

A mixture of 5 parts by weight of aluminum oxide and 25 parts by weight of polyacetal, activated with 0.0015 parts by weight of boron trifluoride, is covered with 40 parts by weight of pentane and cooled to -69 ⁰ C, the batch.

Under reduced pressure, 30 parts by weight of gaseous acetaldehyde are generated in the course of 8 hours introduced into the polymerization vessel and the polymerization batch worked up as usual after 65 hours. The conversion is 41 percent by weight.

Example 5

A mixture of 7 parts by weight of silica gel and 18 parts by weight of polyacetal, activated with 0.0007 parts by weight of boron trifluoride, is covered with 20 parts by weight of pentane and cooled dispersion, the contact to -78 ⁰ C. A cooled acetaldehyde solution, which consists of 20 parts by weight of acetaldehyde and 25 parts by weight of pentane, is then introduced into the contact dispersion under reduced pressure over the course of 9 hours. The approach is worked up as usual. The conversion is 34 percent by weight.

Example 6

A mixture of 10 parts by weight of silica gel and 15 parts by weight of polyacetal, activated with 0.007 parts by weight of boron trifluoride, are overlaid with 30 parts by weight of cyclohexene and cooled dispersion, the contact to -70 ⁰ C. In the course of 6 hours, 27 parts by weight of gaseous acetaldehyde are then passed into the cooled contact dispersion and the polymerization batch is worked up as usual after 30 hours. The conversion is 49 percent by weight.

Claims (1)

PATENT CLAIM: Process for the polymerization of acetaldehyde in the presence of at least one organic and / or inorganic solid contact, which by at least one organic or inorganic acid, a Lewis acid or a Lewis acid in the form of known complex compounds or salt-like compounds in amounts of 0.00005 to 0.1% > Based on the weight of the solid contact, is activated, at temperatures from -30 to -120 ° C, characterized in that the polymerization is carried out in the presence of saturated aliphatic, cycloaliphatic and / or araliphatic hydrocarbons which have no chemical interaction with the catalyst system and stepping on the monomers. Considered publications:
German Auslegeschrift No. 1 037 127;
Makromolekulare Chemie, 1959, Vol. XXXIII, pp. 32 to 40. Legacy Patents Considered:
German Patent No. 1 106 075. 1 sheet of drawings © 309 729/325 10.63