SU1565872A1 - Method of obtaining oils simulating palm oils - Google Patents

Abstract

The invention relates to the oil and fat industry, in particular to methods for producing analogs of solid vegetable oils. The aim of the invention is to approach the oils by their physicochemical properties to the palm ones. This is achieved by metathesis of vegetable oils in the presence of an olefin with the number of carbon atoms from 6 to 28. The process is carried out in the presence of a catalyst based on molybdenum pentachloride fixed on silica gel. The cocatalyst is germanium tetrachloride or silicon. The molar ratio of molybdenum pentachloride: olefin: fat: tetramethyl tin: germanium tetrachloride or silicon is 1: 100–200: 10–20: 4–20: 4–20. The resulting product is hydrogenated in a known manner. Hexene-3, decene-5 or tetradecene-7 are preferably used as olefins. The resulting fat corresponds in iodine number and melting point to coconut, palm or palm kernel oils. 4 tab. 1 hp f-ly.

Description

The invention relates to the oil and fat industry, in particular, to methods for producing analogs of solid vegetable oils.

The purpose of the invention is the approach of the oils to the palm-like physical and chemical properties.

The method is carried out by conducting metathesis of vegetable oils and fats in the presence of an olefin with the number of carbon atoms from 6 to 28 and a catalyst based on molybdenum pentachloride fixed on a slime gel, in combination with a cocatalyst — tetramethyl and an activator — germanium tetrachloride or silicon tetrachloride, with a molar ratio of molybdenum pentachloride: olefin: fat: tetramethyltin: germanium tetrachloride or silicon tetrachloride, equal to 1: (100-200) :( 10-20) :( 4-20) :( 4-20) followed by hydrogenation of modified fat sludge and oils. In the metathesis, it is preferable to use the hexene-3, decene-5 or tetradecene-7 olefins. As a result of metathesis, low molecular weight acyl radicals of laureoleic C p,, meristoleic Ck,, palmitoleic C (-1 acids, the hydrogenation of which leads to the formation of modified fat) are obtained

ЈЈ

0 SL 00

acyl radicals of laurnovic C, g, 0, myristic Cc, a and palmitic Cf6.0 acids.

In the proposed method, linear olefins (monounsaturated hydrocarbons) with the number of carbon atoms from 6 to 28 and a double carbon-carbon bond symmetrically located in the center of the olefin molecule are used. The symmetry of the olefin molecule with respect to the unsaturated bond is desirable, but not limited to fator, since a symmetrical olefin molecule leads to a minimal amount of metathesis reaction products, and the asymmetric arrangement of the double bond in the olefin molecule significantly increases the yield of various, unhealthy, undesirable products. Comrade metathesis reaction.

Schematically, the metathesis can be represented as a redistribution of the double carbon – carbon bonds of two molecules, which occurs at the active centers of the metal complex catalyst and leads to the formation of two new molecules:

EC

 in, -R3

NA CH4-YS CH

In the metathesis of vegetable oils and fats, it is preferable to use olefins with the number of carbon atoms from 6 to 28. If you use olefins with the number of carbon atoms less than 6, acyl radicals with the number of carbon atoms less than 12 will be present in the modified fat molecule, participation in the metathesis of the olefin with carbon atoms more than 28 leads to the formation in the molecule of a modified fat acyl radicals with the number of carbon atoms more than 26. The presence of modified fat acyl radicals with the number of carbon atoms ohms less than 12 and more than 28 is undesirable, since such structures in natural vegetable oils and fats are practically absent.

Olefin in the proposed method; | always take in a significant mole p- Q 5 0

five

0

35

excess in relation to fat: when the molar ratio of olefin to fat is less than 5, crosslinked polymolecular structures are formed that degrade the quality of the final product, and when the molar ratio of components is more than 20, the process is unprofitable, since a large excess of olefin does not have an additional positive effect and therefore does not affect the quality of the final product.

The most reactive fragment of sunflower oil triacylglyceride is the acyl radical of linoleic acid (65-75%), in which the double bond is in 9 positions, in the acyl radical of oleic acid (15-25%) the double bond is only in the 9th position, the acyl radical of stearic acid (3-7%) is completely saturated and does not contain double bonds. In soybean triacylglycerides there are 3-15% of acyl radicals of linolenic acid, in which the double bonds are in 9, 12, 15th positions. I

Thus, the most common subject for considering the metathesis reaction is the acyl radical of linoleic acid, the metathesis of which with hexai-3 leads to:

C3 | C3

12

 g-

 ga-. one -

P-C15 .. “O

+

 9

G cis: i

c, um + se sd

(2)

The metathesis of triacylglycerides of sunflower oil with decene-5 leads to:

CJT-C5

12--1

12

 1V. (

9 (3)

or

 9- Г2 С h, .- 1 + с

n: g

. (four)

The metathesis of triacylglycerides of sunflower oil with tetradecene-7 leads to:

 G2 and: g

12

/ 51 7

+ C, C,

The metathesis of triacylglyceride soybean oil with decene-5 leads

12

Su-st

+

12 9 12

Ve

+

 C s and; s

.

20

P: i

(eight)

12

-,

15

With f {. -...- 25 (9)

As follows from reactions (1) - (9), the metathesis of acyl radicals of linoleic and linolenic acids (with a length of carbon atoms of 18) leads not only to a change in long acyl

five )

ten

15

20

(eight)

 25)

nd x

thirty

When the ratio of cocatalizer (tetramethyl tin) and activator (silicon tetrachloride or germanium tetrachloride) to molybdenum is less than 4, the activity of the catalytic system drops sharply, an increase in these ratios of more than 20 does not affect its activity, but leads to additional and unproductive consumption of the components of the catalytic system .

It is not rational to carry out the metathesis process with a molar ratio of fat to molybdenum less than 10 — in this case, the amount of modified fat relative to molybdenum is low and approaches stoichiometric. When the molar ratio of fat to molybdenum is more than 20, the performance of the catalytic system decreases, the conversion of the original oil and the yield of the target product, modified fat, decrease.

The proposed catalytic system for the metathesis of vegetable oils and fats does not have isomerzing ability. Adverse reactions of skeletal isomerization and positional isomerization of double bonds in the process of metatens do not proceed. In addition, decomposition of modified fats and analysis of ethyl esters using GLC and PNR showed the absence of products

radicals from 12 to 20 carbon atoms

but also to reduce the unsaturation of acyl radicals in reactions (2), (4), (6), (8) and (9). Excess modifier reagent favors preferably reactions (2), (4), (6) and (9) and the production of low molecular weight acyl radicals

C T2M C 4- | 1 AND C. ,

Molybdenum pentachloride fixed on silica gel is used as a metathesis catalyst in combination with a cocatalyst — tetramethylolol and an activator — germanium tetrachloride or silicon tetrachloride.

Catalyst metal is molybdenum; it is absent in the products of metathesis, since molybdenum pentachloride, when it is fixed on the surface of silica gel, is bound to it by covalent chemical bonds, and therefore, it is not washed out from the surface of the carrier during the reaction, which is confirmed by atomic absorption spectroscopy.

Hydrogenation of the modified fat can be carried out on any catalytic system with high efficiency for the hydrogenation of unsaturated acyl radicals of high molecular weight fatty acids, vegetable oils and fats.

The method is carried out as follows.

In a thermostated reactor with a magnetic stirrer, a refrigerator and two dropping funnels placed the catalyst - molybdenum pentachloride fixed on silica gel. Olefin and cocatalyst - tetramethyl tin are loaded into one dropping funnel, fat is loaded into the second column, and germanium tetrachloride or silicon tetrachloride is loaded into the second column. The contents of the first funnel are poured into the catalyst and after 5 minutes the contents of the second funnel. After the completion of the metatheic process, the catalyst is separated, and the catalyzate is subjected to vacuum distillation, removing the excess of unreacted olefin, hydrocarbons resulting from the co-metathesis, as well as the activator, cocatalyst, and their interaction products. The residue contains only modified fat, since it has a significantly greater molecular weight than the listed compounds and reaction products, and therefore it is easy to separate them. The resulting modified fat is hydrogenated in the presence of highly effective catalysts for the hydrogenation of high-fatty acids, vegetable oils and fats. After completion of the process, the melting point, iodine number, pollination number and fatty acid composition of the modified fat are determined. The composition of the fat is monitored by GLC analysis using capillary columns.

Example 1. In a reactor equipped with a thermostatted device, a magnetic stirrer, a cooler, and two dropping funnels, 6.8 g of molybdenum pentachloride are placed on a silica gel (1.65 MO mol). Olefin hexene-3 21.9 g (2.6-10 1 mol) and cocatalyst tetramethyl tin 4.8 g (2.6 -10 mol) are loaded into one dropping funnel. Sunflower oil 29.2 g (3.3 -10 2 mol) and germanium tetrachloride 5.6 g (2.6) are placed in the second funnel. The molar ratio of molybdenum pentachloride: hexene-3:. oil: tetramethyl tin: germanium tetrachloride is 1: 157: 20: 16: 16. The contents of the first dropping funnel are poured into the catalyst, and after 5 minutes the contents of the second one.

The process is carried out for 7 hours with vigorous stirring of the contents of the reactor with a magnetic stirrer, after which the catalyst is separated by filtration and catalyzed; Purified by vacuum distillation at

250 C and a residual pressure of 1 mmHg, this removes the excess unreacted olefin, hydrocarbons, resulting from the methomethesis, cocatalyst, activator, and their interaction products. The residue after distillation is 26.0 g - it is a synthetic oil. Next, synthetic oil is hydrogenated

50

50

d

five

0

0

five

in the autoclave with vigorous stirring in the presence of 0.52 g of catalyst — 0.2% Pd / Al03, under a hydrogen pressure of 1.0 MPa and 14 ° C for 1 hour. The catalyst is separated from the hydrogen acetate by filtration. The modified fat has the following characteristics:: pl. 23 ° C, iodine number 10.2 g J4 / 100 g, saponification number 255 mg KOH.

 The physicochemical characteristics of the fat obtained in Example 1 are presented in Table 1, where for comparison, similar values are given for coconut oil and a synthetic preparation obtained by a known method.

/

As follows from the above data, the proposed method allows to improve the physicochemical characteristics of the modified fat in accordance with the characteristics for coconut oil.

Example 2. The procedure was carried out according to the method described in Example 1, but the decen- ture was used as an olefin. 5. The fatty acid composition of the synthetic oil obtained after the metathesis is presented in Table 2. After hydrogenation, the modified fat has the following characteristics: mp. iodine value 15.4 g Jt / 100 g, saponification number 245 mg KOH.

Example 3. Carried out according to the method described in Example 1, but tetradecene-7 is used as an olefin. Data on the fatty acid composition of the synthetic oil obtained after the metathesis is presented in Table 3. After hydrogenation, the modified fat has the following characteristics: 37 ° C, titer 42 ° C, iodine number 50 g Ja / 100 g, pollination number 175 mg KOH. I The physicochemical characteristics of the modified fats obtained in Examples 2 and 3 are presented in Table 3, where for comparison, similar values are given for palm and palm kernel oils.

Examples 4-10. Carried out according to the method described in example 1, with varying samples of fatty raw materials and process conditions. The results are presented in table 4.

24 ° C

9

Thus, the proposed method of modifying vegetable oils and fats in comparison with the known one has a number of significant advantages: the inefficiency of the known method, in which the initial fatty raw materials are the products of the cleavage of vegetable oils and fats (glycerol, fatty acids or their esters), is eliminated; the production of which consumes a significant amount of energy and scarce fatty material. The feedstock for the implementation of the proposed method is readily available, not scarce fatty raw materials - including liquid vegetable oils and olefins - products of petrochemical refining, the amount of which is not limited. The modified fats obtained by the proposed method contain a significant amount of acyl radicals of lauric, myristic and palmitic acids, which allows their use as substitutes for solid vegetable oils. The proposed method allows to improve the physicochemical characteristics of modified fats, and also to exclude (in case of complete replacement of solid vegetable oils with modified fat) or to reduce the purchase of expensive imported oils - coconut, palm, palm tree or find a more rational use of them: use modified fats as raw material fat for technical purposes of soap

Coconut oil

By a known method (prototype) By the proposed method with hexene-3

872

ten

Reni - production of high-quality varieties of toilet soap, thereby increasing the use of solid vegetable oils for the production of new high-quality food products of soft varieties of low-calorie and dietary margarines. Depending on the organization of the process according to the proposed method, it is possible to obtain a modified fat that, according to its physicochemical characteristics, is close to palm oils.

Claims (2)

1. A method for producing palm imitation oils, distinguishing 0 five 0 five so that, in order to bring the physicochemical properties to palm, the metathesis of vegetable oils and fats is carried out with an olefin of 6 to 28 carbon atoms in the presence of a molybdenum pentachloride catalyst fixed on silica gel in combination with a tetramethyl tin cocatalyst and an activator — germanium tetrachloride or silicon at a molar ratio of molybdenum peitachloride: olefin: fat: or oil: tetramethyltin: germanium tetrachloride or silicon 1: (100-260) :( 10-20) :( 4-20) :( 4-20) followed by hydrogenation get Nogo product. 2. A process according to claim 1, characterized in that olefins use hexene-3, decene-5 or tetradecene-7. Table 1 22-25 254-265 thirty 246-250 23 255 Note. Ch, e, С „, С„ - saturated, mono-and di-saturated oxidative fatty radicals acids; n is the number of carbon atoms in the acid from 12 to 19. Fat sample Iodine number, I Temperature g g (melting, Palmo Palm Wood Oil oil According to the proposed method with decene-5 According to the proposed method C-tetradecene-7 Sunflower nas-Hexen-3 lo 1: 157: 20: 16: 16 table 2 Table 3 Titer.S Saponification number, mg KOH 36-48 42 240-257 196-210 245 175 Table 4 62.4 23 10.2 255