DE1075617B - Process for stabilizing organic compounds or their mixtures against oxidative degradation - Google Patents

Description

GERMAN

The invention relates to the stabilization of organic compounds that cause decomposition Tend to store or during use as a result of oxidation or other reactions. The new procedure according to the invention can be used for the stabilization of various organic substances, which are subject to oxidative decomposition as for motor fuels, especially unsaturated gasoline, z. B. cracked gasoline or polymerized gasoline, diesel oil, mineral oil, lubricating oil, fuel oil, drying oil, Fats, rubber, monomers including styrene, butadiene and the like, paraffin waxes and synthetic edible fats and oils. These substances are oxidized by oxygen, so that either formation of undesirable gummy substances or discoloration or rancidity or other harmful reactions enter.

The invention is particularly applicable to the stabilization of artificial edible fats and oils, which are of animal or vegetable origin and are prone to during long periods of storage to go rancid with use. It should be noted that other oils and fats, previously different treatments, z. B. a blowing with air or a heat treatment, have been subjected to of the invention can be treated.

The method according to the invention consists in that organic compounds or mixtures thereof, which are exposed to oxidative decomposition, stabilized by using an oxyspirochroman with a Spiro bond in 2-S division sets in amounts that delay the decomposition. As a special embodiment of the invention are a fatty acid glyceride or mixtures of fatty acid glycerides Addition of about 0.0001% to about 1% by weight of a 6,7,6 ', 7'-tetraoxy-bis-2,2'-spirochroman stabilized.

Oxyspirochromane, which come into consideration for the stabilization according to the invention, are by the the following general formula is given:

in which A is hydrogen or hydroxyl, R ₁ and R ₂ each represent an alkyl group with 1 to 7 carbon atoms or R ₁ and R ₂ together with the carbon method for stabilization
of organic compounds

or their mixtures
against oxidative degradation

Applicant:

Universal Oil Products Company,
Des Piaines, 111. (V. St. A.)

Representative: Dipl.-Ing. E. Jourdan

and Dipl.-Ing. W. Weinkauff, patent attorneys,

Frankfurt / M., Kronberger Str. 46

Ralph Brewster Thompson, Hinsdale, 111. (V. St. Α.),
has been named as the inventor

Substance atom in position 4 or 4 'denotes a polymethylene ring of 5 to 7 carbon atoms, R ₃ denotes hydrogen when R ₁ and R _{2 are} both a methyl group, or denotes _{an alkyl group with an alkyl group smaller by one CH 2} group than R _{2 when} R _{1 is} methyl and R _{2 is} greater than methyl; R _{4 is} hydrogen when either R ₁ or R _{2 is} methyl, or is an alkyl group with one CH ₂ group less than R ₁ when both R ₁ and R _{2 are} greater than methyl when R ₁ and R ₂ together with the carbon atom in position 4 or 4 'denote _{a polymethylene ring, R 3} and R ₄ together represent a polymethylene chain, the ends of which are connected to the molecule in positions 3, 3' to form a polymethylene ring of 5 to 7 carbon atoms.

The oxyspirochromes are presented in a manner known per se. The properties of the particular oxyspirochromant produced depend on the particular reactants used in the manufacture. According to a known method, hydroquinone can be condensed with acetone, "so that the resulting oxyspirochroman from 6,6'-dioxy-4,4, 4 ', 4'-tetramethyl-bis-2,2'-spirochroman. In general, those are when using hydroquinone Yields obtained as the starting compound are not very satisfactory, which is why oxyhydroquinone is preferred used as a starting compound. The condensation of oxyhydroquinone with acetone yields 6,7,6 ', 7'-tetraoxy-4,4,4', 4 '- tetramethyl-2,2'-spirochro-Es it should be noted that when using

man

909 730/524

Oxyhydroquinone the * Oxyspirochroman hydroxyl groups in the 6,7 and 6 ', 7' positions.

The stabilizing agent according to the invention is the organic compound to be stabilized in generally in amounts of less than 1 percent by weight, preferably in an amount of about 0.0001 up to about 1 percent by weight, added. One uses when stabilizing synthetic edible fats and oils generally about 0.001 to about 0.5 weight percent, and for gasolines generally above about 0.02 percent by weight stabilizer. The stabilizing agent can be used alone or in admixture with others Additions such as Br acting synergistically Compounds, dyes and anti-knock agents depending on the starting compound to be stabilized, be used. In the stabilization of synthetic edible fats and fatty oils can act as synergistic compounds, for example phosphoric acid or ascorbic acid, usually in the range of about 0.0001 to about 0.5 weight percent, along with be added to the stabilizer. When stabilizing in gasoline according to the invention can Tetraethyl lead, a dye and perhaps synergistic compounds, such as certain types of alkyl polyamines, can be added.

The following examples serve to explain the

Invention.

example 1

Various defined oxyspirochroman compounds according to the invention were used in a concentration of 0.005 percent by weight for the stabilization of Lard used without stabilizers according to the "Swift" test, which is also used below than the A.O.M. method (active oxygen method)

ίο is designated a shelf life of 6 hours would have. The determination method for this is in "OIL AND SOAP", Vol. X, 1933, No. 6, pp. 106 to 109, and in a modified form in "OIL AND SOAP", pp. 169 to 171, of September 1943, described. In general This test consists in passing air through a sample of the lard heated to 98 ° C blows until the rancidity can be perceived by taste and determined by peroxide values. The results of these tests are referred to as the A.O.M. stability period, which is expressed in the number of hours

• the one that is required to achieve a peroxide number of 20 are required. The following table also contains experiments carried out in the presence of 0.01 weight percent phosphoric acid have been carried out as a synergistic compound.

Table oxyspirochroman compound

attempt
No.

Chemical name

Boiling point of
Spirochromes

Oxidation delay period

(Hours) after the active
Oxygen determination method

Stabilizers and phosphoric acid as
synergistic
■ Active agents

Stabilizers

6,7,6 ', 7'-tetraoxy-4,4,4', 4'-tetramethyl- (bis-2,2'-spirochroman)

6,7,6 ', 7 ^/ -Tetraoxy-3,4,4'-trimethyl-4,4'-diethyl

(up to-2,2'-spirochroman)

bis- (6,7-Dioxy-3-trimethylene-4,4-penta-methylene-2-spirochroman)

6,7,6 ', 7'-tetraoxy-4,4'-dimethyl-4,4'-di-n-amyl-3-n-butylbis- (2,2'-spirochroman)

6,7,6 ^/ , 7'-tetraoxy-4,4,4 ', 4 ^/ -tetraethyl-3,3'-dimethyl- (to ^^' - spirochroman)

265 to 267
214 to 215
292 to 294
204 to 205

55
45
47
46
27

65
68
69
50

It should be noted that the oxyspirochroman compounds of the present invention have the A.O.M. stability period of lard increased from 6 hours to a considerably higher time value. In general it should be noted that a stability period of 20 hours is common for all practical purposes is sufficient, which means that the oxidation stability of the lard under the usual conditions, as they apply to storage and household use for a period of 6 to 9 months, is sufficient. The addition of the oxyspirochroman compounds according to the invention can apparently the lard can be stored for a considerably longer period of time without the risk of becoming rancid.

Example 2

0.075 percent by weight of oxyspirochroman compounds of experiments 2 and 3 according to Table 1 were used for used the stabilization of a Pennsylvania mineral oil that had an induction period without a stabilizer of about 100 minutes. The addition of these oxyspirochroman compounds to the gasoline served to increase the induction periods, as can be seen from the following table.

Table 2

attempt
No. Spirochroman connection Induction
duration*)
(Minutes) 1
2
3 no
6,7,6 ', 7'-tetraoxy-3,4,4'-tri-
methyl-4,4'-diethyl-bis-
(2,2'-spirochroman)
bis- (6,7-dioxy-3-tri-
methylene-4,4-p enta-
methylene-2-spirochroman) about 100
685
795

*) Induction duration means the time span in minutes until a rapid drop in the time-pressure curve occurs, which is obtained in an autoclave with a gasoline sample of 100 cm ³ (with or without stabilizing agent) under an initial oxygen pressure of 7.8 at at 20 ° C and subsequent steam heating to 100 ° C was observed. The maximum pressure here is approximately 9.5 at.

Example 3

0.075 percent by weight 6,6'-dioxy-4,4,4 ', 4'-tetramethyl-bis- (2,2'-spirochroman) from the F. = 210 to 212 ° C was a Pennsylvania cracked gasoline with the natural Added induction period of about 90 minutes. After adding the oxyspirochroman compound the gasoline had an induction period of 660 minutes. ". .

Example 4

6,7,6 ', 7'-tetraoxy-4,4,4', 4'-tetramethyl-bis- (2,2'-spirochroman) Effectively stabilized styrene when this compound was at a concentration of 0.01 percent by weight to which styrene was added. The effectiveness of the stabilizing agent can be determined in the following way will. A sample of styrene with no stabilizer and another sample of the styrene with the above Oxyspirochromanverbindungen were enclosed in a separate small glass tube, the had a long thin neck; the tubes were kept at 80 ° C for 10 hours or at a higher temperature and / or for longer periods of time, if necessary, heated. Periodically the pipes became conversely, and the change in viscosity was determined by observing the "bubble time"; H. the time it took for a bubble to rise to the top of the thin neck when the tube was at 25 ° C was reversed. The increase in viscosity indicated degradation of the sample by reactions such as oxidation, resin formation and polymerization.

Example 5

This example illustrates the use of an oxyspirochroman compound according to the invention in the stabilization of rubber. 0.4 percent by weight bis- (6,7-dioxy-3-trimethylene-4,4-pentamethylene-2-spirochroman) were added to the milk obtained from the emulsion polymerization of butadiene and styrene, whereupon the milk was coagulated and dried. The rubber thus produced is of concern its color, strength and elasticity are improved.

Claims (3)

PATENT CLAIMS: 1. Process for the stabilization of organic compounds or mixtures thereof against the oxidative degradation, characterized in that an oxyspirochroman of the general formula R ₁ R ₂ in which A denotes hydrogen or hydroxyl, R ₁ and R ₂ each represent an alkyl group with 1 to 7 carbon atoms or R ₁ and R ₂ together with the carbon atom in position 4 or 4 'denote a polymethylene ring of 5 to 7 carbon atoms, R ₃ denotes hydrogen when R ₁ and R _{2 are} both a methyl group, or _{denotes an alkyl group with an alkyl group smaller by one CH 2} group than R ₂ when R _{1 is} methyl and R _{2 is} greater than methyl; R _{4 is} hydrogen when either R ₁ or R _{2 is} methyl, or is an alkyl group with one CH ₂ group less than R ₁ when both R ₁ and R _{2 are} greater than methyl when R ₁ and R ₂ together with the carbon atom in position 4 or 4 'denote _{a polymethylene ring, R 3} and R ₄ together represent a polymethylene chain, the ends of which are attached to the molecule in positions 3,3' to form a polymethylene ring of 5 to 7 carbon atoms, in amounts, which retard this degradation, preferably in amounts of 0.0001 to 1.0 percent by weight of the organic compound to be stabilized. 2. The method according to claim 1, characterized in that the organic compound by Addition of a 6,6'-dioxy-bis- (2,2'-spirochromans) is stabilized. 3. The method according to claim 1, characterized in that the organic compound by addition of a 6,7,6 ', 7'-tetraoxy-bis (2,2'-spirochroman) is stabilized. 909 730/524 2.60