DE1794403B2 - METHOD OF DISTILLING TALLOEL - Google Patents

Description

il)

in which η is at least 1, m is O or at least 1, ρ is a number from 0 to 100, χ is a number from 1 to 3, aryl is phenyl, naphthyl or anthracyl and R is a hydrocarbon radical having 1 to 22 carbon atoms means, undertakes.

2. The method according to claim 1, characterized in that there is used as the treatment compound Polythioresorcinol is used, for which ρ has a value from 5 to 20.

3. The method according to claim 1, characterized in that there is used as the treatment compound 4,4'-thiobisresorcinol or 2,2'-thiobis (4-methyl-6-tert-butylphenol) is used.

(OH) _n (OH) _n (OH) (Aryl) - S _x -
j - (Aryl) -S _x - - (aryl) (R) ,,, (R) ,,, , (R) ,,,

The invention relates to a new method for distilling tall oil by evaporation at temperatures from about 240 to 275 "C at a pressure of about 50 to 100 mm and then condensing.

As a starting material for the erfindungsgcmäße Tall oil used for purposes is a mixture of resin and fatty acids obtained by acidifying the "Black liquor soap" is released. The black liquor soap separates itself as so-called "scummings" on the surface of the "black liquor", which consists of the alkaline digestion liquid that is used in the Sulphate or "Kraft" process for making paper is washed out of the pulp. That Crude tall oil is then usually subjected to fractional or steam distillation, whereby different fractions are obtained, those of resin-FcUsäuremischungen with a fatty acid content of only about 1 percent by weight and a resin content of about 99 percent by weight, usually up to to about 90 percent by weight, to other such Mixtures range in which the resin content is less than about 1 percent by weight, e.g. B. 0.3 percent by weight, and the fatty acid content about 99 percent by weight, e.g. B. 99.3 percent by weight.

The term »tall oil fraction with predominantly fatty acid content«. As used herein, crude sovent säureraflinicrtc and distilled tall oil fractions as well as tall oil products obtained by fractional distillation, each having a fatty acid content of at least about 50 percent by weight, while the remainder consists mainly of resin acids in addition to smaller amounts of unsaponifiable substances with a complex chemical composition. The fatty acids consist mainly of a mixture of oleic acid, linoleic acid, linoleic, palmitic and stearic acid compounds along with smaller amounts of palmitoleic acid, saturated acids of higher molecular weight, e.g. B. arachidic acid (C ₂₀ ), behenic acid (C ₂₂ ), unsaturated and polyunsaturated acids with a higher molecular weight and low-boiling monobasic and dibasic acids.

Tall oils preferred for the treatment according to the invention are the commercially available acid solvent-refined tall oils. These consist of raw tall oils. those in a hydrocarbon solvent, e.g. B. hexane, in a weight ratio of about 40 parts Tall oil slurried to 60 parts of hexane, then with about 8 to 12 percent by weight 96 to 100% conc. Sulfuric acid at about 35 to 40 C''t have been treated and separated. Such refined tall oils generally contain about 50 percent by weight or more fatty acids, while the remainder consists of resin acids, dimerized resin acids and unsaponifiables.

Further preferred tall oils are the commercially available tall oil fractions. which is at least 90 percent by weight Fatty acids and contain a maximum of 5 percent by weight resin acids, while the remainder is made up consists of smaller amounts of intricately structured unsaponifiable substances.

For many areas of application for Tallö ¹ , it is important that the material is lightly colored and that the color remains the same under normal conditions of use. For example, resin compounds are widely used in the production of paper glue, as plasticizers for films, e.g. B. made of polyethylene and polypropylene, and used for the production of synthetic resins for paints and varnishes. For this and other purposes a light colored product is required which is also color stable.

In order to stabilize the improved color obtained in this way, it has become customary to use known antioxidants admit it.

The known methods for lightening and stabilizing tall oil fatty acids are effective, they however, have some major disadvantages. So some of the fatty acids together become mil coloring Substances are adsorbed on the adsorbents and are lost when the adsorbed material is discarded which results in additional costs for the bleached product obtained. 1 one A second anti-oxidant treatment is often required to improve color to stabilize. This further increases the effort for the end product.

It is known that crude tall oil can be produced by heating to an elevated temperature prior to distillation or by treatment with sulfur. Sulfur dioxide. .Iodine and similar materials can be bleached a little. However, these methods require a fairly high outlay, since additional facilities and Process stages are required after the distillation of the crude tall oil. In addition, the Tall oil color improves, but stability is

often bad, and tall oil tends to decompose to such an extent that the effect of bleaching is so great is canceled again.

DT-PS 9 14 884 describes a process for refining tall oil and distillates obtained from it. Raffinates and fractions described, which consists in the fact that the material to be refined in the presence of basic catalysts subjected to a heat treatment. The heat treatment takes place expediently with the exclusion of air and ι ο under an inert gas atmosphere, and as basic catalysts are oxides or hydroxides of alkali metals or alkaline earth metals or basic reacting Salts of alkali metals or alkaline earth metals with weak acids such as carbonic acid are used.

The disadvantage of the above process, however, is that the catalysts used after completion Refinement treatment through the action of acids with heating and subsequent washing out must be removed from the treated mixture with water, as described on page 2, lines 59 to 63 and in detail on page 2 from line 109 to page 3, line 2. Without such a Aftertreatment does not result in a product that is satisfactory in every respect. That with the invention Thiobisphcnol used in the process, on the other hand, does not have to be removed after treatment , whereby this process is much less expensive.

According to "Tall Oil Refining", 1952, pp. 44 to 45 in connection with page 54, crude oil is purified using certain chemicals, in particular conc. Sulfuric acid. Since the reaction products obtained are due to the high The viscosity of the reaction mixture can only be separated off with difficulty and only with great effort Reaction either carried out directly in the presence of a solvent, or the reaction mixture has to be used after the reaction has taken place, dilute with this solvent. The solvent used for this must be insoluble in water so that the reaction products can be washed out. As a committed Solvents are listed as pctrolether and naphtha. This procedure is also a long one more expensive than a simple distillation of tall oil in the presence of a certain treatment compound, which leads directly to a usable product.

The process according to the invention is now characterized in that the evaporation is carried out in the presence from about 0.01 to 1 percent by weight of a treatment compound of Formula 1

(OH) ₁₁ (OH) ,,

i 1

(AnI) S _v (aryl) H)

1 ;

(Ri ,,,

(Aryl) S _v

in which 11 is at least 1. m is 0 or at least 1, ρ is a number from 0 to 100, .v is a number from 1 to 3. Aryl for phenyl. Naphthyl or anthracyl and R is a hydrocarbon: it means ¹ , with 1 to 22 carbon atoms, represents. The phenol sulfide used is preferably a polythioresorcinol. where ρ has a value from 5 to 20. In particular, 4,4'-thiobisresorcinol or 2,2'-thiobis (4-methyl-6-tert-butylphenol) are used. The amount of treating compound used is preferably 0.05 to 0.2 percent by weight based on the weight of the tall oil.

The hydrocarbon radical R is z. B. an alkyl, cycloalkyl or substituted alkyl radical, for example having 1 to 8 carbon atoms, in which the substituents consist of cycloalkyl, aryl, alkaryl groups and the like. The radical R preferably has 1 to 22 carbon atoms. Preferred alkyl groups are straight-chain, secondary and tertiary alkyl groups with up to 8 carbon atoms. Preferred aryl groups are those which have 6 to 18 carbon atoms contain. Examples are phenyl, naphthyl and anthracyl. Typical cycloalkyl groups contain 3 up to 8 ring carbon atoms, e.g. B. cyclopropyl, cyclopentyl and cyclohexyl.

If the aryl radicals given in the above formula I consist of phenyl radicals, then the sum of m and π on each phenyl ring for p = 0, as can be clearly seen, is not more than 5. and when ρ is 1 or a higher value has, the sum of m and / 1 on any phenyl ring is no greater than 4. However, it also makes sense. that 11 and in can assume higher values if the aryl radicals given in the formula consist of naphthyl or anthracite radicals, since then more than 5 or 4 positions are available for OH and R substituents if ρ is 0 or at least 1 means. Here values for in, η. With the exception of the value 0, χ and ρ are positive integers.

The formula given above includes compounds and positional isomers with R groups of a mixed nature. d. H. the groups or groups R on an aryl ring may differ from those on the other aryl ring. »1 and» 1 can be for each aryl ring be the same or different, and if more than one Group R is present on an aryl ring. such groups can be the same or different.

From the repeating unit of the formula 1 given above it can be seen that for the purposes according to the invention not only thiobis compounds (p = 0). but also substances with a high molecular weight, in which / .. B. ρ is a value of 100 or more, come into consideration, provided that a sufficient number of sites are available for polymerization, e.g. B. that the sum of J! and in. if the specified aryl radical consists of a phenyl radical, does not exceed 4. The upper limit for the molecular weight depends only on it. how the connection is made, e.g. B. whether the material in the reaction medium is sufficiently flowable for further polymerization. as well as the conditions of use. /. E.g. whether the material can be effectively mixed for good contact with the bleaching material. A polymer of such a high molecular weight that it is sticky or glassy and can no longer be handled is, of course, to be avoided in the practice of the inventive method / 11. For economic reasons and because they are easy to prepare and use for the purposes of the invention, preferred treatment agents are those which are soluble in the material being treated. z. B. Compounds of Formula I. wherein ρ has a value in the range from 5 to about 20.

Typical examples of treatment agents according to the invention are the following:

Thiobisnaphthols, e.g. B.

1,1'-thiobis-onaphthol),
2,2'-thiobis ((i-naphthol),

2,2'-thiobisphenols, e.g. B.

2,? 'Thiobis (4-methyl-6-tert.-butylphenol),
2,2'-thiobis (4,6-dimethylphenol),

3,3'-thiob: spbenole, e.g. B.

3,3'-thiobis [methyl-6- (l, l, 3,3-tetramethyl-

butylphenol],

3,3'-thiobis (raethyl-6-tert-dodecylphenol),
3,3'-thiobis (pentadecyl-7-butylphenol).

4,4'-thiobisphenols, e.g. B.

4.4'-thiobis (3-methyl-6-tert-butylphenol).
4,4'-thiobis-3-methyl-6- (1 -methylcyclohexyl) -

phenol,
4,4'-thiobis (2-methyl-6-tert-butylphenyl).

Thiobis polyhydroxy compounds, e.g. B.
4,4'-thiobis (resorcinol), 5,5'-thiobis (pyrogai "iol).

as well as the di- and trithiobis derivatives of the above-mentioned compounds and substances with higher Molecular weight with corresponding repeating units of the abovementioned compounds.

Particularly preferred are the polyhydroxy compounds, such as. B. 4,4'-thiobis (resorcinol) and 5,5'-thiobis (pyrogallol), the so-called "sterically hindered" (thiobisphanols, e.g. those in which each aromatic ring is spaced apart by a hydroxyl group Group, e.g. a secondary or tertiary alkyl group, and a short straight-chain (C ₁ -C ₈ ) alkyl group is substituted and compounds with a higher molecular weight, in which ρ has a value in the range from 5 to 20. Typical examples of the » Sterically hindered thiobisphenols are 2,2'-thiobis (4-methyl-6-tert-butylphenol), 4,4'-thiobis (6-tert-butylcresol) and 4,4'-thiobis (6-tert .-buty'-cresol). Of the thiobisphenols, the first mentioned shows the best results, and it was found that when the sulfur atom is shifted from the o-position to the hydroxyl group and the methyl group from the p-position to the o- A typical example of the higher molecular weight compounds is polythio- (resorcinol), where ρ is a W ert from 6 to 9 has.

The treatment conditions can and are therefore varied in fairly wide ranges not particularly critical. The order of mixing the treatment compound and tall oil is also not critical. Even very small amounts of the additive are effective "Catalytic" amounts can be referred to, e.g. B. about 0.01 to 1.0 weight percent, preferably 0.02 to 0.5 percent by weight of the treatment compound based on the weight of the starting material. The treatment compounds can be used individually or as mixtures of two or more compounds can be applied.

In the case of the tall oil fatty acid fraction, good bleaching and color stability are generally achieved when this fraction for about 5 minutes to 5 hours at a temperature in the range of about 200 to 300 C treated, where the lower temperature corresponds to the longer treatment time and vice versa, The treatment is preferably carried out for about 15 minutes to one hour in a temperature range from about 240 to 275 ° C, with time and temperature being inversely proportional. Little or none Bleaching and color stabilization is done at high temperatures

ίο found below about 200 ⁰ C, and above about 300 ⁰ C decomposition and polymerization begins, especially in tall oil fractions that have a higher content of fatty acids, z. B. from 75 to 99%. The method according to the invention can be used as required

i <; can be carried out at atmospheric, negative or positive pressure with the appropriate temperature setting. It is also possible to work batchwise, semicontinuously or continuously.
The process of the invention can be carried out in conjunction with a conventional destination of crude tall oil or fractional distillation of distilled tall oil. In either of these cases, the tall oil can be heated first in the presence of the treating compound and then distilled, or during each stage while the tall oil is temporarily held at an elevated temperature.

Any distillation process can be used, e.g. B. steam, dry vacuum or Molecular distillation. Of these methods, steam distillation is preferred because it is higher Allows temperatures and pressures without decomposition of the tall oil. The conditions for steam distillation can be changed depending on the selected pressure and temperature will. Preferred conditions are a temperature of about 250 to 275 "C under vacuum or a pressure of about 50 to 100 mm until a desired water vapor / oil ratio is reached or until the distillation has practically ended. The steam distillation can, if appropriate, be carried out directly a fractional distillation follow, which is also carried out under customary conditions. Preferred Conditions for the fractional distillation are a steam temperature of about 170 to 230 C and a pressure of about 4 mm, until the fractionation has practically ended.

All of the processes described above can be batch, semi-continuous, or continuous and the order of addition is not critical. So the tall oil can before adding the Treatment agent to be heated a little, or you can first add the treatment agent and then distill the mixture.

The bleaching and color stabilizing effect achieved according to the invention is very surprising since it was not to be expected that the compounds of formula I. many of which are known antioxidants. Bleach tall oil as well as the lighter colored products obtained would stabilize against decomposition and discoloration. The reasons for this behavior could so far cannot be fully elucidated, however, it is believed that the whitening effect is due to one Conversion of the coloring substances in tall oil is based.

The following examples illustrate the invention without restricting it. Get parts and percentages always based on weight, unless otherwise stated.

Examples I to 3

The following is a typical way of working for the inventive lightening of crude tall oil described. s

The reaction vessel of a conventional steam distillation apparatus was charged with crude tall oil and TBP, ie 2,2'-thiobis (4-methyl-6-tert-bulylphenol) in the amounts indicated. The mixture was then brought to about 250 to 275 C and a pressure of about 50 mm and distilled with steam until the distillation was practically complete. Table 1 shows the effect of the thiobisphenol additive on the distillate color and the stability of the color compared to a control. The Färb resistance was tested through one hour heating the sample in air at 110 ⁰ C (oven). The specified color values are based on the Gardner 1933 standard scale, in which the colors become lighter as the size of the numbers decreases. A 20 1 ratio of 12 corresponds to a reddish color, 9 to an orange-red color, 6 to the color of tea and 1 to a pale yellow color. In the case of commercial varieties of tall oil, color values in the range from 6 to 1 are generally required. The values show a reduction in the colors by three points (9 ⁺ to 6 "), so that according to the invention commercial tall oil qualities are obtained without the considerable expense of post-heating and other treatment measures. The table below also shows that the stability at each example is better than that of the control. The best stability is achieved when at least about 0.1% of the thiobisphenol is used, conventional apparatus and fractionally distilled in a known manner (about 170 to 230 ° C. at 4 mm) with the exception that the distillation was carried out in the presence of 0.1% of the same thiobisphenol (TBP) as used in Examples 1 to 3. The results can be seen in Table.] In comparison with the control, each fraction with the exception of The fractions 1 to 5 represent mixtures of resin and fatty acids, the latter predominating (about 50% or more) rbgrade is based on the Gardner 1933 standard scale, and the color values given last are based on the USDA standard scale (N and WG are 1 and 2 points brighter than M, respectively).

Table 11

Distilled tall oil
Controls

Table 1 example

4 5

Column creasing residue
(Resin)

% the
Feed ti τι u

3.0

4.3
15.3
15.3
12.3

6.1

42.9

l-'arbe

9 ⁺

4-

2 +

4 "

Mil 0.1% TBP distilled tall oil

% the color

feed

2.9

3.9 15.0 15.2 15.8

6.3

41.9

% TBP

comparison - 1 0.1 2 0.05 3 0.01

Dcstillate color

9 ⁺
6 "

T
7+

Color stability of the distillate

12 "
9 ⁺

H ⁺

Example 4

Tall oil obtained by steam distillation from crude tall oil in a conventional manner was treated with a

Example 5

According to the procedure described in Examples 1 to 4, tall oil samples were in the presence of 0.1 weight percent 4,4'-thiobis (resorcinol). l.l'-thiobis (^ - naphthol) and a polythioresorcinol compound of the formula I. in which ρ is the number 8, distilled whereby tall oil was obtained with a considerably lighter color and improved color stability. If mar Tall oil fractionally distilled in the presence of the treatment agent produces practically the same results nits received.

Claims (1)

Patent claims: 1. Process? To distill tall oil by evaporation at temperatures of about 240 to 275 ⁼ C at a pressure of about 50 to 100 mm and subsequent condensation, characterized in that the evaporation in the presence of about 0.01 to 1 percent by weight of a Treatment connection of the formal