SI8912204A8 - Process for hydrogenation of oils - Google Patents

Abstract

There is disclosed a process for hydrogenation of vegetable or animal oils, wherein the oil is hydrogenated, optionally in a solvent, with a hydrogen donor in the presence of a phase transfer catalyst, which reduces the iodine values of the starting materials from the values of 50 to 183 to the values of 10 to 150. According to said process, hydrogenation products having very good properties are obtained.

Description

The field of technology

The invention is in the field of food technology and relates to a process for the hydrogenation of vegetable and animal oils into products with a single melting profile, by catalytic transfer of hydrogen in the presence of a suitable catalyst.

A technical problem

There was a need to provide a process for producing hydrogenated oils with special characteristics, such as solid content index (SCI), iodine number (IV), and high stability2 at room temperature and to provide also a simple and quick one-step process for producing said hydrogenated oils.

The state of the art

The essential characteristics of products containing hydrogenated oils such as margarines, ice creams, cakes, etc., especially mouthmelt, are due to the SCI content of hydrogenated oils. In order to achieve the desired SCI, which determines the quality in the temperature range from 10 ° C to 30 ° C, i.e.

SCI of 40-70, 45-56 oz. 10-30, novel and effective hydrogenation processes are required to obtain the fats with the desired melting properties. The basic hydrogenation process is the conversion of liquid oils into semi-solids, i.e. plastic fats used for the production of vegetable fats, margarines and dedicated fats. Hydrogenation also achieves increased stability and improvement of the base color.

Hydrogenation is the adherence of a double bond of fat in the presence of a metal catalyst. Its purpose is to saturate the double bonds of fatty acids in fats. The hydrogenation reaction is not easy, as it is accompanied by the simultaneous isomerization of the double bonds, which can be positional as well as geometric. The location of the fatty acid on glycerol (alpha and beta) as well as the degree of unsaturation determine the physical properties of the molecule, especially the fat melting point, and thus affect SCI. The reaction proceeds stepwise from the most unsaturated fatty acid to the saturated state, e.g. from linoleic to linoleic, then to oil and finally to stearic acid. With normal hydrogenation, they cannot reach a narrow melting range or a controlled level of trans acids.

The literature describes methods for hydrogenating oils, especially vegetable oils, at temperatures from 190 to 230 ° C and pressure gauges from 0 to 7.10 ^ Pa (U.S. Patent 4,169,843,

Synder et al., And U.S. Pat. Patent 3,459,777, Seiden et al.).

In the last patent, the catalyst is gradually added to achieve the desired level of hydrogenation. Catalysts are common No catalyst or sulfur poisoned or. deactivated Ni catalyst. General information is also described in JAOCS vol.60 (2), 1983, p. 282-290, Beckmann Hydrogenation Practice.

EP Patent Application 0 246 366 A1 describes a simplified one-step process with partially deactivated Ni catalyst at a temperature of 16O-25O ° C and a pressure gauge of water from 0 to 7-10 Pa.

Description of solution to a technical problem with implementation examples

The present case is also a one-step procedure. All reactants are simultaneously batch-reacted and reacted in the first stage either in a batch reactor or reacted on a continuous flow reactor at flow through a catalyst prepared on a suitable carrier. Instead of molecular hydrogen, a hydrogen donor is used which is dissolved in a solvent or suspended in oil and which, on contact with the catalyst (preferably palladium) and the substrate, forms nascent hydrogen. The process is carried out at room temperature. Better results are achieved at 60 to 80 ° C.

So we hydrogenate at a temperature of 20 to 80 ° C, usually at room temperature, and better results are obtained by gradient temperature rise as well as atmospheric pressure.

In batch mode, we work in solvent or without solvent in emulsion. We are continuously working in the solvent.

Hydrogenates oils containing fatty acids with at least 12 carbon atoms. We obtain products with specific compositions that are the basis for making margarines, vegetable fats, creams, ice creams, etc., which require improved edible and suitable melting properties.

With this kind of hydrogenation, the oil must be in contact with the acceptor (A) containing double bonds, a hydrogen donor (DHx) and a catalyst. A hydrogen donor can be any organic matter that has an oxidation potential low enough to carry out hydrogen transfer under relatively mild conditions.

The reaction is carried out according to the following formula:

DHx + nA -> - n AHx + 1)

The rate of hydrogenation depends on the nature of the oil, the nature of the hydrogen donor, the activity and concentration of the catalyst, and the rate at which the unsaturated oil and hydrogen donor are adsorbed or. desorbed on the catalyst. The compositions and properties of the hydrogenated products may vary depending on the location of the double bonds that are hydrogenated, as well as the effect of the isomerization reaction, which is a concomitant reaction of each hydrogenation and is highly dependent on the hydrogenation conditions.

As vegetable oils or mixtures of vegetable oils containing fatty acids with at least 12 carbon atoms in the chain, for example, e.g. soybean, sunflower, safflower, corn, olive, bamboo, peanut, palm, rapeseed, grape,

A 'coconut and castor oil.

Fish oil or a mixture of fish oil with vegetable oils can be used as animal oil.

We use regenerable catalysts such as palladium on activated carbon (Pd / C), namely 5% Pd / C, 10% Pd / C, 20% Pd / C, Pd / C / FeCl ^ (10%) , Pd / C / Fe (III) hydroxide or oxide, Pd / C / NaBH ^ (10%), rhodium on activated carbon (5%), Raney nickel, ruthenium black and platinum black.

A 0.03 to 1% catalyst is used per oil and fat inlet mass. The catalyst can be suspended in oil or in a solvent.

The catalyst must be suitable for a hydrogen donor, so we use formic and phosphic acid and their salts, triethylammonium formate, tri-n-butylammonium formate, sodium phosphinate, sodium formate and ammonium formate in our work.

When hydrogenating in a solvent, coordination of solvent, donor, and hydrogen acceptor interactions is also important. If the bond between the solvent and the catalyst is stronger than the donor-acceptor bond, the catalytic transfer reaction does not proceed. We choose e.g. among the following solvents such as ethanol, propane-2ol, formic acid, acetic acid, acetone and ethyl acetate. Some solvents may also act as a hydrogen donor.

The reaction may be carried out to products which may be completely or partially hydrogenated oils.

The resulting product has an SCI of greater than 6 at about 33 ° C and an SCI value range of at least about 17 at a temperature between 21 and 33 ° C.

The essential advantages of the process according to the invention in comparison with the prior art are efficiency, simplicity, the possibility of using conventional equipment (autoclaves are not required), energy savings and possible catalyst regeneration.

The continuous process is simpler than the batch process because neither mixing nor removing the catalyst is required. The catalyst can also be regenerated in the column and can therefore be used indefinitely.

However, it is not necessary to work with solvent in batch mode. Hydrogenation can take place in an emulsion, so there is no problem of removing the solvent, as well as the hydrogen donor, if it is water-soluble, since it remains in the aqueous phase after the reaction is complete after separation of the water and oil phases.

The process described belongs to a series of hydrogenation reactions by catalytic transfer of olefins described in the basic examples in Tetrahedron Letters 29 (44) 5559-5600; B.Elamin et al., And in JAOCS 64 (11) 1529-1532, 1987; 0. Arkad et al.

EXAMPLES

In the batch mode (Examples 1 and 2), use a 100 ml flask as a reaction vessel into which a certain amount of hydrogenated oil is weighed. A hydrogen donor dissolved in the solvent is added to the oil and finally the catalyst is stirred. The catalyst, oil and hydrogen donor suspension is mixed with a laboratory mixer at about 900 rpm. Mixing is necessary to ensure a constant renewal of the oil and hydrogen donor on the catalyst surface where the reaction takes place. In some experiments, the suspension is continuously heated with a heater, which in some donors accelerates hydrogen emission.

For continuous operation (example 3), use a 30 cm high glass column with a diameter of 1 cm. The column is equipped with a Teflon cock. Up to 1 cm in height, it is filled with celite over which a catalyst is applied. The oil and the hydrogen donor are dissolved in a solvent and this solution is eluted through the column.

EXAMPLE 1

Add 1 ml of oleic acid to the flask and add 25 ml of acetone, 0.5 ml of formic acid, 2 ml of triethylamine and 100 mg of 10% Pd / C. The mixture was stirred mechanically at room temperature and atmospheric pressure for 15 hours. The mixture is heated to a final temperature of about 30 ° C due to the exothermic reaction. Removal of the solvent gives predominantly stearic acid. Unreacted remains approximately (due to poor separation on a gas chromatograph) of 10% oleic acid.

EXAMPLE 2

Add 1 ml of sunflower oil with an iodine number of 139.2 + 3 to the flask and add 25 ml of acetone, 0.5 ml of formic acid, ml of triethylamine and 100 mg of 10% Pd / C. The mixture was stirred mechanically at room temperature and atmospheric pressure for 15 hours. After removal of the solvent, a hydrogenated product was obtained with an iodine number of about 20.

The iodine number is calculated from the fatty acid composition.

Table 1 lists the fatty acid composition of sunflower oil and hydrogenated product.

TABLE 1

Fatty acid Sunflower oil (IV = 139,2 + 3) * Hydrogenated Oil (IV ~ 20) palmitic (C16: O) 8.3 9.7 stearic (C18: O) 2.9 <85,1 oleic (C18: 1) 23.5 V linoleum (C18: 2) 65,2 5.2 linoleum (018: 3) 0.1 0.0 together 100% 100%

* The error stems from the error of gas chromatographic determination of fatty acids.

EXAMPLE 3

Through a column filled with celite and 100 mg Pd / C, a mixture of 2 ml of sunflower oil with iodine number 139.2 + 3, ml of acetone and 2 ml of formic acid was eluted. The flow rate is 0.5 ml / min.

Removal of the solvent gives a hydrogenated product with an iodine number of 122.4 + 3 ·

Table 2 lists the fatty acid composition of sunflower oil and hydrogenated product.

TABLE 2

Fatty acid Sunflower oil (IV = 139,2 + 3) * Hydrogenated Oil (IV = 122.4 + 3) palmitine (06: 0) 8.3 io; o Stearin (08: 0) 2.9 3.0 oleic (C18: 1) 23.5. 38.5 linoleum (C18: 2) 65,2 48.5 linoleic (C18: 3) OJ 0.0 together 100% 100%

* The error stems from the error of gas chromatographic determination of fatty acids.

Method for determining fatty acid composition

Weigh exactly 100 mg of fat or oil into a glass teflon stopper and add 2 ml of 10% BF ^ in methanol. Close the bottle well and heat to

120 ° C. After 5 minutes, add 1 ml of hexane to the contents and heat for another 5 minutes. 1 µl of hexane phase is injected into the gas chromatograph injector.

Gas Chromatograph: VARIAN 3700

Column: 15% OV-275 on Chromosorb WAW 80/100, 2 m long

Detector: flame ionization

Carrier gas: nitrogen, flow rate 30 ml / min

Temperature program: 150 to 200 ° C, 8 ° C / min

Injector temperature: 200 ° C

Detector temperature: 210 ° C.

Claims (10)

PATENT APPLICATIONS A process for the hydrogenation of oils of animal and vegetable origin, characterized in that the oil is hydrogenated in the temperature range from 20 to 80 ° C at atmospheric pressure, optionally in a solvent, with a hydrogen donor in the presence of a iodine-reducing phase transfer catalyst inputs from values 50 to 183 to values 10 to 150. Process according to claim 1, characterized in that formic or phosphinic acid or their salts, triethylammonium formate or tri-n-butylammonium formate, sodium phosphinate, sodium formate or ammonium formate are used as the hydrogen donor. Process according to claim 1, characterized in that the vegetable oils or mixtures of vegetable oils consisting of fatty acids with at least 12 carbon atoms in the chain are hydrogenated. Process according to Claims 1 to 3, characterized in that the vegetable oils are soybean, sunflower, saffron, corn, olive, bamboo, peanut, palm, rapeseed, grape, coconut and castor oil. Process according to Claims 1 and 2, characterized in that hydrogenated fish oil or a mixture of fish oil with vegetable oils. Process according to claims 1 to 5, characterized in that palladium on activated carbon, Pd / C / FeCl ₃ , Pd / C / Fe (III) hydroxide or oxide, Pd / C / NaBH ₄ , rhodium on activated carbon, Raney nickel, ruthenium black or platinum black. The process according to claims 1 to 6, characterized in that an organic solvent such as n-pentane, isopropanol, ethanol, acetone, dimethylformamide, and water is used as the solvent. The process according to claims 1 to 7, characterized in that the amount of solvent is 100 to 500% by weight per inlet of oils and fats. Process according to claims 1 to 8, characterized in that from 15 to 200% by weight of the hydrogen donor is used per input mass of oils and fats. The process according to claims 1 to 9, characterized in that 0.03 to 1% by weight of catalyst is used per input mass of oils and fats.