FR2798381A1 - Preparation of a calcium complex used as a PVC formulation stabilizer comprises reacting calcium (hydr)oxide with a beta-dicarbonyl compound in a 1-6C saturated alcohol and/or 2-6C ether - Google Patents

Abstract

Preparation of a complex of calcium and a beta -dicarbonyl compound comprises reacting calcium (hydr)oxide with the beta -dicarbonyl compound in a solvent from 1-6C saturated alcohols and/or 2-6C ethers in a ratio of solvent to Ca (hydr)oxide of 1-10.

Description

 PREPARATION OF CALCIUM CHELATES <B> <B> <B> PRESENCE <B> OF A SOLVENT OF THE ALCOHOL TYPE </ B> The present invention relates to a process for the preparation of calcium complexes and (3-dicarbonyl compounds, implemented in the presence of a solvent chosen from saturated alcohols or saturated ethers.

Calcium chelates and 3-dicarbonyl compounds are well known compounds and are very often used as stabilizing agents for halogenated polymers.

The subject of the present invention is therefore a process for the preparation of such complexes that makes it possible to access compounds having, inter alia, a correct coloration for the subsequent application of the product.

Thus, the process according to the present invention consists in reacting the calcium oxide or hydroxide with the α-dicarbonyl compound, in the presence of a solvent chosen from saturated alcohols comprising 1 to 6 carbon atoms, the ethers comprising 2 to 6 carbon atoms, used alone or in combination. In addition, the weight ratio of the solvent to the oxide or the calcium hydroxide is between 1 and 10.

More particularly, the weight ratio of the solvent to the oxide or the calcium hydroxide is between 1 and 8.

The solvent is thus chosen from saturated alcohols containing 1 to 6 carbon atoms, and of reference from those comprising 1 to 4 carbon atoms.

According to a particular embodiment of the invention, said solvent is selected from methanol, ethanol, propanol, isopropanol, alone or in mixtures. Preferably, the solvent used is methanol.

The solvent used in the reaction can likewise be chosen from saturated ethers comprising 1 to 6 carbon atoms. By way of example of such ethers, mention may be made inter alia of diethyl ether or diisopropyl ether, alone or as mixtures. It is likewise possible to use cyclic ethers, for example for example, tetrahydrofuran.

A very advantageous mode of the present invention consists in carrying out said reaction in the presence of a solvent chosen from saturated alcohols. This solvent may be an alcohol or a mixture of several of them.

The (3-dicarbonyl) compound is more particularly chosen from β-diketones and also β-ketoesters These compounds more particularly correspond to the following formulas R'-CO-C (R 2) 2 -CO-R 1 and R 1 -CO-C (R 2) 2-COOR ', wherein R', which may be identical or different, each represents a hydrocarbon radical, preferably having from 1 to 30 carbon atoms, preferably from 1 to 18 carbon atoms, R2 is a hydrogen or a hydrocarbon radical, in general alkyl, advantageously having at most 4 carbon atoms, It should be noted that the two radicals R 'may be connected in such a way that the carbonyl compound forms a ring.

According to a more particular embodiment of the invention, the R 'radicals of the α-dicarbonyl compound, which are identical or different, may be chosen from linear or branched alkyl or alkenyl radicals having up to 24 carbon atoms, aralkyl radicals having 7 to 10 carbon atoms, aryl or cyclic radicals having less than 14 carbon atoms; the cyclic radicals possibly comprising carbon-carbon double bonds.

It is likewise specified that these radicals may be substituted or unsubstituted, for example by halogen atoms or, for aryl, aralkyl or cyclic radicals, by methyl or ethyl radicals.

The previously enumerated radicals may also be modified by the presence in the aliphatic chain of one or more of the groups of formulas -O-, -C0-0-, -CO-.

The radicals R 'may also represent, together, a single divalent radical having from 2 to 5 carbon atoms and which may comprise an oxygen or nitrogen heteroatom.

As for the radicals R2, identical or not, they represent a hydrogen atom, or a substituted or unsubstituted alkyl radical having from 1 to 4 carbon atoms and capable of being interrupted by -O-, -C0-0- , -CO-. More particularly, the radicals R 2, which are identical or different, represent a hydrogen atom or a methyl radical. Preferably, the radicals R2 represent hydrogen.

It should be noted that the process according to the invention is particularly suitable for obtaining complexes of calcium and of compounds chosen from (3-diketones.) Even more advantageously, the process is used for obtaining complex of calcium and acetylacetone.

The reaction according to the invention is more particularly covered with a molar ratio of the compound [3-dicarbonylated oxide or calcium hydroxide between 2I1 and <I> 2,4I1. </ I> the process according to the invention is carried out in the presence of a molar ratio of between 211 and 2,2I1. Note that the reagent involved in the process according to the invention is preferably calcium oxide (lime). The lime commercially available is suitable for the covering of the invention. The contacting is carried out more particularly with stirring. Preferably, the reaction is carried out in a turbosphere-type reactor, or any other apparatus provided with mechanical stirring means allowing a good homogenization of the reaction mixture.

According to a particular embodiment of the invention, the contacting is carried out by introducing the compound (3-dicarbonyl in a mixture comprising the oxide and / or calcium hydroxide and the solvent.

According to an advantageous embodiment of the invention, the reaction is conducted at a temperature greater than or equal to room temperature. More particularly, the reaction is carried out at a temperature between room temperature (20 C) and that of boiling the solvent or solvent mixture. The reaction can therefore be carried out with a reflux of solvent.

The contacting can be carried out under an inert atmosphere (such as nitrogen or a rare gas) or in air.

The duration of the operation is typically from one hour to four hours.

Once introduced, the solvent is removed from the reaction mixture. This operation may take place by distillation of the solvent or by filtration of the reaction mixture. As previously indicated, complexes of calcium and β-dicarbonyl compounds are generally employed as stabilizing agents for halogenated polymers, which are more particularly chlorinated polymers.

The content of complex is more precisely between 0.01 and 2 g per 100 g of halogenated polymer. More particularly, the content of complex is between 0.05 and 1 g relative to the same reference.

The complex obtained according to the process of the invention may advantageously be used as a stabilizer for polyvinyl chloride (PVC) based formulations.

By polyvinyl chloride is meant compositions whose polymer is a homopolymer of vinyl chloride. The homopolymer can be chemically modified, for example by chlorination.

Many copolymers of vinyl chloride can also be stabilized using the composition according to the invention. In particular, they are polymers obtained by copolymerization of vinyl chloride with monomers having an ethylenically polymerizable bond, such as, for example, vinyl acetate or vinylidene chloride; maleic, fumaric acids or their esters; olefins such as ethylene, propylene, hexene; acrylic or methacrylic esters; styrene; vinyl ethers such as vinyldodecyl ether.

Usually the copolymers contain at least 50% by weight of vinyl chloride units and preferably at least 80% by weight of such units. PVC alone or mixed with other polymers is the most widely used chlorinated polymer in stabilized formulations.

In general, any type of polyvinyl chloride is suitable, regardless of its method of preparation. Thus the polymers obtained for example by using bulk, suspension or emulsion processes can be stabilized using the composition according to the invention, and this regardless of the intrinsic viscosity of the polymer.

The formulations may additionally contain the stabilizing additives conventionally employed in this field. A concrete but non-limiting example of the invention will now be presented. <B> EXAMPLE </ B> After purging a turbosphere reactor with nitrogen, 3 kg of calcium oxide and 6 kg of methanol are introduced.

11 kg of acetylacetone are then introduced over 1 hour, with stirring and at room temperature.

Once the introduction is complete, the mixture is heated and the reaction mixture is maintained at 95 ° C. for 1 hour. Methanol is distilled.

The reaction mixture is then kept under vacuum at 50 mbar for 1 hour.

The resulting product is then dried (rotary evaporator). Calcium acetylacetonate is obtained.

The yellow index (coefficient b) of the product is 5.88. The coefficient b is one of the parameters of the system (L, a, b) CIE, measured using a chromometer-colorimeter MINOLTA CR 200.

Claims (9)

<B> CLAIMS </ B> A process for preparing a calcium complex and a 3-dicarbonyl compound, wherein the calcium oxide or hydroxide is reacted with the dicarbonyl compound, wherein the reaction is carried out in the presence of a a solvent selected from saturated alcohols having 1 to 6 carbon atoms, ethers comprising 2 to 6 carbon atoms, used alone or in combination, the weight ratio of solvent to oxide or calcium hydroxide being between 1 and 6; 10. 2. Method according to the preceding claim, characterized in that the weight ratio of the solvent to the oxide or calcium hydroxide is between 1 and 8. 3. Method according to any one of the preceding claims, characterized in that the solvent is selected from saturated alcohols comprising 1 to 4 carbon atoms. 4. Method according to the preceding claim, characterized in that the alcohol is selected from methanol, ethanol, propanol, isopropanol, alone or in mixtures. 5. Method according to any one of the preceding claims, characterized in that the ether is chosen from diethyl ether, diisopropyl ether, or from cyclic ethers such as tetrahydrofuran; alone or in mixtures. 6. Method according to any one of the preceding claims, characterized in that the molar ratio of the compound (3-dicarbonylated oxide or hydroxide is between 211 and <I> 2,4I1. </ I> 7. Method according to any one of the preceding claims, characterized in that the reaction is carried out at a temperature greater than or equal to room temperature. 8. Process according to any one of the preceding claims, characterized in that the reaction is carried out by introducing the compound> dicarbonyl in a mixture of oxide and / or calcium hydroxide and solvent. 9. Process according to any one of the preceding claims, characterized in that the solvent is removed at the end of the reaction, by filtration or by distillation.