DE977275C - Process for deodorizing higher molecular weight, unsaturated fatty alcohols - Google Patents

Description

ISSUED SEPTEMBER 9, 1965

H13914 IVb J12

Fatty alcohols

Higher molecular weight, unsaturated fatty alcohols and their esters, which are found in certain oils of marine origin are included, such as B. in the sperm oil of the sperm whale, provide valuable raw materials for various Branches of chemical engineering represent, however, their applicability through theirs adherent tranquil odor severely impaired. It is possible to remove this odor by hydrogenation to eliminate, but this process is often not to be used with the alcohols to be processed recommend because hydrogenation affects the unsaturated nature of the material. If one tries, higher molecular weight, unsaturated fatty alcohols according to other common methods to deodorize, as has also been suggested for Trane or fish oils, for example by According to experience, bubbles with possibly superheated water vapor in a vacuum the inventor to a certain degree of success, but the unpleasant tranquil smell occurs that way after a certain storage time.

It has now been found that the unpleasant odor of higher molecular weight, unsaturated fatty alcohols can be permanently removed if these alcohols are heated to temperatures above about 250 ^° C. for some time and then malodorous decomposition products are removed from the alcohols.

509 654/4

The return of the tranquil odor after deodorization with steam is evidently due to the fact that the unsaturated alcohols contain substances which are able to re-form them after the originally present odor carriers have been removed. If this assumption is correct, it is the lasting deodorization, which can be reached by the inventive process, probably explained by the fact ίο that when heated to temperatures above 250 ⁰ C, not only the scents themselves, but also those substances are destroyed from which the odorous substances can form again.

In addition to the already mentioned sperm oil or those obtained from it, the starting material can be used Alcohols also through the reduction of higher molecular weight, unsaturated fatty acids of marine origin obtained higher molecular weight, unsaturated alcohols are used.

The upper limit for the treatment temperature is to be regarded as that at which significant decomposition, in particular dehydration, of the alcohols occurs. However, this depends not only on the working temperature but also on the other reaction conditions. The decomposition of the alcohols, in particular the dehydration, can be suppressed, for example, by working in enamelled apparatus or in containers made of refined steels. Working in the presence of water is also recommended. Under these circumstances it is of course necessary to work in pressure vessels, which is also expedient if, because of the high reaction temperature, significant amounts of alcohol can be distilled off. The treatment time depends on the temperature chosen and the material to be treated and can generally be shorter, the higher the temperature is kept. While a few hours are usually necessary at temperatures around 250 ^° C., a significantly shorter treatment time can be sufficient ^{at 300 ° C.} In this way it is possible to destroy almost exclusively the odorous substances, while the treated alcohols do not undergo any significant changes. The decomposition products of these odorous substances often give the treated alcohol a typical odor which, however, can easily be removed by treating the material with steam or inert gases or by other methods, for example by vacuum distillation. If the heating of the alcohols in the presence of water under pressure has taken place, the foul-smelling decomposition products can be driven off by the steam produced when the hot reaction mixture is let down. The treatment according to the invention hardly changes the material; in particular, no significant polymerization occurs. In the products deodorized in this way, no recurrence of the tranquil odor was observed.

As with all unsaturated fatty substances, those treated according to the invention can also be used under unfavorable storage conditions, such as B. when standing in the presence of air, auto-oxidize, a process that occurs with the recurrence of the tranquil smell in the case of improperly deodorized Fatty alcohol has nothing to do and by adding antioxidants such as aromatic hydroxyl or amino compounds and natural inhibitors such as tocopherols, guaiacum resin and the like Substances that can be prevented. The effectiveness of these inhibitors can be achieved through combination be strengthened with synergistic substances.

It is known that fish oils or fish fatty acids can be improved odorless by polymerization at elevated temperatures. In the process according to the invention, however, no significant polymerization takes place. Since it is generally believed that the presence of clupanodonic acid is the cause of the tranquil odor of fish oils, it was not foreseeable that such a process would also be applicable to alcohols which do not contain clupanodonic acid. It is also known to use low-quality fats such as B. Heringstran or Döglingsöl, with one of the saponification to saponify appropriate amount of highly concentrated alkali metal hydroxide solution while introducing superheated steam and increase the temperature up to 350 ⁰ C. The alcohols released during the saponification are exaggerated. In contrast to the processing according to the invention, this is a deodorization of the soaps and not of the alcohols, which are also driven over with the aid of steam, which is not the case with the process according to the invention. Also could not be found in this known method is that the same are destroyed by heating to temperatures above 250 ⁰ C in the higher molecular weight, unsaturated fatty alcohols marine origin odor substances contained or precursors.

It is also known to heat ^{fish oils to 250 to 300 °} C. for a few hours for the purpose of deodorization. However, the higher molecular weight, unsaturated fatty alcohols to be deodorized according to the invention are not obtained by saponifying fish oils. These alcohols are not found in fish oils at all, but in very few oils from marine mammals. The main source of higher molecular weight, unsaturated fatty alcohols is sperm oil, which essentially only occurs in the head cavities of the sperm whale. For this reason it was not to be expected that a deodorization process carried out with fish oils would also be successful with higher molecular weight, unsaturated fatty alcohols which are of completely different origin.

However, there is no difference between the known method and the method according to the invention only of a formal nature, but must also be due chemically to other processes. this it follows that, after a long time, deodorized fish oils will regain their develop characteristic odor while the

higher molecular weight, unsaturated fatty alcohols deodorized by the process according to the invention remain odorless even after long periods of storage. ■:

Example ι

396 kg of a Spermölalkohols (JZ = 83, OH value = 208, acid number = 0.2) were heated in a glass lined vessel with agitator to 300 ⁰ C. The air had been displaced by nitrogen. The product was kept at this temperature for 3 hours. During the experiment, 0.6 kg of an oily and 1 kg of an aqueous condensate distilled off. After cooling, the product was heated 1V2 hours at 150 to 170 ⁰ C at 9 mm Hg and this injected steam. The temperature was then increased to 170 to 190 ⁰ C and the product was increased by introducing it

ao amounts of steam distilled over in vacuo. A residue of 2.9% remained in the distillation. That The distillate obtained was almost water-white and practically odorless (JZ = 81, OHZ = 207, SZ = 0.3). If necessary, a slight pre-run and post-run can be separated off during the distillation will.

Example 2

319 kg of a crude, undistilled alcohol from sperm oil (JZ = 54, OH value = 218) were heated for 4 hours at 280-290 ⁰ C, and 1.2 kg 1.9 kg oily and aqueous condensate distilled off. Mm by blowing in vacuo at 8 mm of 150 ° C with direct steam and subsequent distillation at 8 and 190 ⁰ C with the addition of greater amounts of steam was after separation of 4 ° / o lead and 3 ° / o tracking a water-white, practically odorless product obtain. The distillation residue was 7%. The same material left 6.5% residue on distillation without the pretreatment mentioned. The main fraction showed the following analytical figures: JZ = 51, OHZ = 217.

Example 3

250 kg of an alcohol made from sperm oil were ^{heated to 260 °} C. for 8 hours. After working up in accordance with Examples 1 and 2, an almost colorless, practically odorless product was obtained. The analytical numbers of the treated product had hardly changed compared to the starting material.

Example 4

ι kg of sperm oil alcohol (JZ = 83, OHZ = 208) was heated in an autoclave made of V4A steel together with 10% water for 30 minutes at 330 ^° C. with stirring. After steam treatment in vacuo, the reaction product showed the following parameters: JZ = 77, OHN = 205, and was practically odorless.

If antioxidants are added to the deodorized products, this can result in a special one Shelf life, d. H. a suppression of becoming rancid can be achieved.

Claims (3)

Patent claims: 1. A process for deodorising higher molecular weight, unsaturated fatty alcohols, characterized in that the fatty alcohols are ^{heated to temperatures above about 250 °} C. and then malodorous decomposition products are removed therefrom. 2. The method according to claim 1, characterized in that that the heating is carried out in the presence of water in pressure vessels. 3. The method according to claim 1 and 2, characterized in that when heating the Decomposition products formed from alcohols are removed by blowing with steam. Considered publications:
British Patent No. 327,990. © 609 656/477 9.56 (509 654/4 9.65)