SK279772B6 - Method of tall oil production - Google Patents

Abstract

Disclosed is a process of a tall oil production; the said tall oil made out of a sulphate soap which is a side-product of the cellulose industry; the said sulphate soap being acidified by hydrochloric acid and thus gained tall oil is separated.

Description

The invention relates to a process for the production of tall oil from kraft soap produced as a by-product in the cellulose industry and to the separation of tall oil so produced from mother water and lignin.

BACKGROUND OF THE INVENTION

Valuable kraft soap is produced as a by-product in the cellulose industry by collecting from the solution level in the production of industrial cellulose, while the mother liquor is concentrated by evaporation of water. Kraft soap is wiped off the surface of the container and acidified to produce tall oil. The tall oil is further distilled to yield valuable bituminous acids and fatty acids as distillation fractions. The reaction is chemically simple and the bitumen and fatty acids present in the form of sodium salts react with sulfuric acid to give the carboxylic acids, respectively. sodium sulfate. Up to now, sulfuric acid has been used to acidify sulfate soap, which is very suitable for this purpose since it allows the addition of neutralized sulfuric acid to the chemical cycle of the holender. The sodium sulphate thus obtained is a useful additive to replace sulfur losses in the manufacture of industrial cellulose. However, due to environmental constraints, sulfur excretion has been reduced in the holenders to such an extent that sulfuric acid used in the acid soap method can no longer be used to replace substantially reduced sulfur losses in the holenders.

The separation of tall oil by acidifying the sulfate soap with sulfuric acid is disclosed e.g. U.S. Pat. No. 3,948,874. Of course, the above-mentioned disadvantages relating to environmental disturbance also apply to this solution. In addition, sulfuric acid is relatively expensive and its use entails high production costs. Therefore, great efforts have been made to develop an alternative solution in the process of acidification in tall oil production.

SUMMARY OF THE INVENTION

The above disadvantages are largely eliminated by the process for producing tall oil from kraft soap and by separating the resulting tall oil according to the invention, which is characterized in that the acidification is carried out with hydrochloric acid.

In one preferred example of the process, the acidification is carried out at a temperature of 60 ° C to 220 ° C, in particular at a temperature of 86 ° C to 100 ° C.

This acidification is carried out under a pressure in the range of 100 to 2353 kPa at a temperature above 100 ° C.

The acid value of the oil thus obtained is 100 to 160 mg KOH / g.

Thus, in the process of the invention, hydrochloric acid is used instead of sulfuric acid to acidify the sulfate soap. Surprisingly, it has been found that although the hydrochloric acid is monovalent, while the sulfuric acid is bivalent, the amount of hydrochloric acid required to process a certain amount of sulfate soap is equal to the amount of sulfuric acid needed to process the same amount of sulfate soap. This unexpected finding is further illustrated in the Examples. Hydrochloric acid is cheaper, easier to achieve, and waste water produced by acidification with hydrochloric acid is more environmentally friendly than waste water produced by acidification with sulfuric acid. In terms of corrosion properties, sulfuric acid and hydrochloric acid are very similar. However, under certain conditions and at a certain concentration, sulfuric acid is more corrosive than hydrochloric acid.

Diluted, concentrated or gaseous hydrochloric acid may be used, provided that the amount is sufficient to neutralize the fatty and resin acids in the sulfate soap. Excessive use causes higher costs. When processing the sulfate soap at boiling water temperatures above 100 ° C, pressure reactions arise and a pressure reactor must be used. The reaction time is not very important, but it has been found that 10-30 minutes is most suitable. No benefits were found for longer periods.

The resulting crude tall oil according to the invention is of a better quality than tall oil produced with sulfuric acid and contains less or no water. When using sulfuric acid, insoluble organic salts such as calcium sulfate and barium sulfate are present in the crude tall oil. When using hydrochloric acid, the corresponding chlorides are soluble in water and do not enter the tall phase but remain in the "mother liquor" and thus do not cause problems in the distillation of tall oil.

The quality changes of kraft soap depend on the quality of the wood used in the production of technical pulp. When only pine is processed, a good grade kraft soap is produced wherein the acid value of the tall oil obtained therefrom is 140 to 160 mg KOH / g and the bitumen acid content is 30 to 50% by weight. However, in birch processing, the quality of the sulfate soap varies so that the acid value of the tall oil in question is 100 to 120 mg KOH / g and is even lower; the resin acid content is then 20 to 30% by weight.

Regardless of quality, hydrochloric acid can be suitably used in the tall oil production process by acidifying sulfate soap instead of sulfuric acid.

After carrying out the process by acidifying the sulfate soap, the tall oil layer can be separated from the mother water and the lignin layers by separation or centrifugation.

The invention will be illustrated by the following examples.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

42 ml of 37 wt.% Hydrochloric acid were used, to which 42 ml of water was added. The mixture was heated to 80 ° C. 190 g of 50% by weight kraft soap were gradually added to the mixture. The mixture was stirred at 80 ° C for 10 minutes and at 90 ° C for 15 minutes and then poured into a glass measuring vessel. The mixture was allowed to separate in layers at 80 ° C for 30 minutes, after which tall oil could be decanted from the settled layers. The analysis of the tall oil obtained was as follows:

* yield% by weight 57.5 acid number mg KOH / g 150 bitumen acid wt. % Unsaponifiable% wt. % Fatty acids wt. 54 * calculated from base: separated tall oil / kraft soap x 100 wt.

Example 2

50 ml of water were used to which 50 ml of 40 wt. sulfuric acid. The mixture was heated to 90 ° C and 200 g of sulfate soap heated to 45 ° C was added. The mixture was stirred at 80 ° C for 10 minutes and at 90 ° C for 15 minutes and then poured into a glass measuring vessel. The mixture was allowed to separate in layers at 80 ° C for 30 minutes after which tall oil could be decanted from the sedimented layers. The analysis of the tall oil obtained was as follows:

* yield% by weight 55 acid number mg KOH / g 150 bitumen acid wt. 35 unsaponifiable substances wt. % Fatty acids wt. 53 * calculated from base: separate tall oil / kraft soap x 100 wt.

In Examples 1 and 2, a gas chromatographic analysis was performed on a chromatography column using a butanediol succinate liquid phase (BDS) in a 25-meter quartz capillary column. The process was performed isothermally at 197 ° C. The main components were:

Example 1 Example 2 9-Octadecenic acid 14.6 wt. 14.4 wt.

9.12-octadecadienoic acid 20.5 wt. 19.9 wt.

7.13-Abietadienoic acid 13.1 wt. 11.7 wt.

8.1 l, 13-abietatrien-18-oic acid 7.0 wt. 7.0 wt.

From the above results, it is clear that the use of hydrochloric acid is fully comparable in quality and yield of tall oil as compared to the use of sulfuric acid.

Example 3

34 ml of 37 wt. hydrochloric acid, to which 34 ml of water was added. The mixture was heated to 90 ° C. 280 g of sulfate soap heated to 50 ° C were gradually added to the mixture. The mixture was stirred at 90 ° C for 30 minutes and then poured into a glass measuring vessel. The mixture was allowed to separate in layers at 90 ° C for 60 minutes after which tall oil could be decanted from the sedimented layers. The analysis of the tall oil obtained was as follows:

* yield% wt.21 acid number mg KOH / g 108 water wt% 4,5 resin acids wt% 34 unsaponifiable wt% 12 * calculated from base: separate tall oil / kraft soap x 100 wt.

Example 4

34 ml of 37 wt. hydrochloric acid, to which 34 ml of water was added. The mixture was heated to 90 ° C. 150 g of sulfate soap heated to 50 ° C were added to the mixture. The mixture was stirred at 90 ° C for 30 minutes and then poured into a glass measuring vessel. The mixture was allowed to separate in layers at 90 ° C for 60 minutes after which tall oil could be decanted from the sedimented layers. The analysis of the tall oil obtained was as follows:

* yield% wt.37 acid number mg KOH / g 149 water wt% 1,5 resin acids wt% 32,7 fatty acids wt% 51,4 non-saponifying agents wt% 15,9 * calculated from the base: separated tall oil / kraft soap x 100 wt.

In Examples 3 and 4, a gas chromatographic analysis was performed on a chromatography column using a butanediol succinate liquid phase (BDS) in a 25-meter quartz capillary column. The process was performed isothermally at 197 ° C. The main components were:

Example 3 Example 4 9-Octadecenic acid 14.3 wt. 17.7 wt.

9.12-octadecadienoic acid 19.3 wt. 24.7 wt.

7.13-Abietadienoic acid 11.6 wt. 16.0 wt.

% 8,11,13 -abietatrien-18-oic acid 7.8 wt. 5.9 wt.

From the above results, it is evident that changing the ratio of soap to hydrochloric acid does not have a major influence on the quality of the separated oil, but only on the rate of layer separation.

Example 5

34 ml of 37 wt. hydrochloric acid, to which 34 ml of water was added. The mixture was heated to 60 ° C. 190 g of sulfate soap heated to 50 ° C were added to the mixture. The mixture was stirred at 60 ° C for 30 minutes and then poured into a glass measuring vessel. The mixture was allowed to separate in layers at 90 ° C for 75 minutes after which tall oil could be decanted from the sedimented layers. The analysis of the tall oil obtained was as follows:

* Yield% 26 acid number mg KOH / g 151 bitumen acid% wt.35 fatty acids% wt.52 non-saponifying agents% wt.13 * calculated from base: separate tall oil / kraft soap x 100% wt.

As a result, it is clear that at low temperatures the yield is lower and the layers are more difficult to separate.

Example 6

63 g of sulfate soap, 11.3 ml of 37 wt. hydrochloric acid and 11.3 ml of water. These components were placed in an autoclave and the temperature was raised to 170 ° C. The mixture was stirred at 170 ° C for 30 minutes, then allowed to cool and the separated tall oil was decanted. The analysis of the tall oil obtained was as follows:

% yield wt. % Acid number mg KOH / g 134 bitumen acid wt. % 32.9 fatty acids wt. % 52.4 unsaponifiable substances wt. 14.7 * calculated from base: separated tall oil / kraft soap x 100 wt.

In Examples 5 and 6, gas chromatographic analysis (BDS column, 197 ° C, isothermal process) was performed. The main components of tall oil were as follows:

Example 3 Example 4 9-Octadecenic acid 14.7 wt. 13.9 wt.

9.12-octadecadienoic acid 20.4 wt. 18.2 wt.

7.13-Abietadienoic acid 19.7 wt. 18.8 wt.

8.11.13-Abietatrien-18-acid 6,8 wt. 10.2 wt.

Example 7

34 ml of 37 wt. hydrochloric acid, to which 34 ml of water was added. The mixture was heated to 97 ° C. 190 g of sulfate soap heated to 50 ° C were added to the mixture. The mixture was stirred at 97 ° C for 30 minutes, then poured into a glass measuring vessel and after a while the separated layer of lignin and tall oil from the mother water was decanted. The mixture was poured into a centrifuge tube and was centrifuged with a relative centrifugal force according to the formula: b = 1.12 rn ² , where b is the relative centrifugal force, r - the centreline distance of the sample, ie the radius and, for example, the rotation speed. It is the force used to centrifuge the solution for 20 minutes for separation. The analysis of the tall oil thus obtained was as follows:

% yield wt. % Acid number mg KOH / g 152.5 non-saponif. 13.2 * calculated from base: separate tall oil / kraft soap x 100 wt.

Based on gas chromatographic analysis (BDS column, 197 ° C, isothermal process), the main components of tall oil were as follows:

Example 8

63 g of sulfate soap, 11.3 ml of 37 wt. hydrochloric acid and 11.3 ml of water. These components were placed in an autoclave and the temperature was raised to 220 ° C, the pressure was 1400 kPa. The mixture was stirred at 220 ° C for 30 minutes, then allowed to cool and the separated tall oil was decanted. The analysis of the tall oil obtained was as follows:

* yield% wt.49 acid number mg KOH / g 124 bitumen acid wt% 29 fatty acids wt% 48 non-saponifying agents wt% 19 * calculated from base: separate tall oil / kraft soap x 100 wt.

Of course, the low acid value of the separated tall oil is due to esterification and decarboxylation.

The tall oil obtained according to Example 8 was subjected to gas chromatographic analysis (BDS column, 197 ° C, isothermal process). The main components of tall oil were as follows:

9-Octadecenoic acid

9,12-octadecadienoic acid

7,13 -Abietadienoic acid

15.5 wt.

15.5 wt.

11.3 wt.

% 8,11,13-abietatrien-18-oic acid 15.9 wt.

Based on gas chromatographic analysis, it appears that there are differences in the acid distribution at this high temperature compared to previous analyzes, and isomerization of 9,12-octadecadienoic acid and 7,13-abietadienoic acid occurs.

PATENT CLAIMS

Claims (6)

A process for the production of tall oil from kraft soap by acidifying kraft soap and separating the obtained tall oil, characterized in that the acidification is carried out with hydrochloric acid. Production method according to claim 1, characterized in that the acidification is carried out at a temperature of 60 ° C to 220 ° C, in particular at a temperature of 85 ° C to 100 ° C. Production method according to claims 1 and 2, characterized in that the acidification is carried out under a pressure of 1400 kPa at a temperature above 100 ° C. 4. A process according to claim 1 wherein the acid value of the tall oil thus obtained is 100 to 160 mg KOH / g. 9-Octadecenoic acid 9.12- octadecadienoic acid 7.13-Abietadienoic acid 8.1,13-abietatrien-18-acid 15.3 wt. 14.0 wt. 25.0 wt. 7.8 wt. End of document