DD161205A3 - METHOD FOR PRODUCING BRIGHT HARDWOOD REFINANTS AF MONTANEWAX BASE - Google Patents

Abstract

The invention relates to a process for the preparation of a bright Hartwachraffinates on Montanwachsbasis. The light hard wax raffinate is obtained according to the invention by oxidative refining with sulfuric acid and chromic acid or alkali metal dichromate crude montan wax in admixture with 5 to 30% by weight of natural or synthetic, saturated or unsaturated fatty acids or fatty acid mixtures with a chain length of C4 to C12.

Description

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Process for the preparation of light hard wax waxes based on montan wax>

Field of application of the invention

The invention relates to a process for the preparation of light hard wax refined by refining with sulfuric acid and chromic acid or alkali metal dichromate, which are suitable for the production of self-gloss emulsions.

Characteristic of the known technical solutions

For Rohmontanwachsraffim tion a variety of methods are known. The workup by distillation with steam is considered unfashionable and outdated. The light products produced by this process are of low quality, because the relatively high thermal stress causes a large part of the natural hard wax to break down into paraffinic products. Another disadvantage is the low refining yield of about 30 % .

Other processes which contain oxygen donating products as refining agents, such as. As hydrogen peroxide, chlorates or potassium permanganate, have no significance industrially, since the refining effect achieved is too low. The lack of nitric acid-sulfuric acid refining, however, is that only about 50 % Raffinatwachsausbeute is achieved and that for the Hachbehandlungsstufen significant amounts of time, energy

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and adjuvants are necessary.

Modern rawanhaon refining processes use sulfuric acid and chromic acid or alkali dichromate as refining agents. Tight procedures work with considerable refining overhead so that the processes are technologically controlled safely. The high refining agent consumption of about 85 to 160 Ma .% CrO 2, based on the raw continuous wax used, has a disadvantageous effect on the economics of the processes. They also have the disadvantage that, as in the case of the application of chromic acid and the electrolytic regeneration of the resulting chromium-III-salt solution, they are extremely energy-intensive. Known, but industrially 'important, are processes that work with nitric acid and subsequent refining with sulfuric Uichromatlöeung. The quality of the raffinates produced is impaired by nitro compounds. Ss are also those processes which use as crude product a composition of raw montmic wax with anoxidiertem hard paraffin or polyethylene for refining, known · The disadvantage of these methods is that due to the high proportion of waste, which is up to 80 % , the wax-specific properties of the raffinate , such as gloss and hardness adversely change · Furthermore, no increase in the acid number of the feed mixture is achieved by these blending components. To increase the acid number of the crude product, although it is known to zuzumisohen higher fatty acids, but in this case the effect in the separation of the liquid-liquid phase of the reaction mixture can be achieved only by high amounts of fatty acids.

Object of the invention

It is an object of the invention to overcome the drawbacks of the prior art and produce a bright hard wax raffinate on Montanwachsbasis to expand the applications of deep brown to black Rohmontanwachse, as well as to create opportunities that to achieve the required acid number of the raffinate refining agent is saved ,

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Explanation of the essence of the invention

The object of the invention is to provide a process for the preparation of montan wax raffinate by oxidative refining with sulfuric acid and chromic acid or alkali metal dichromate.

According to the invention, the object is achieved by a process in which the crude product used for refining contains a mixture of 70 to 95% by weight of a partially aerated raw alcohol wax and 5 to 30% by weight of a natural or synthetic, saturated or unsaturated fatty acid a chain length of C. to C ₁₂ represents. According to the acid value of the raw permanent wax and the mixture component, the mixing ratio of raw montan wax: mixture component of 2.3 to 19 * 1 can be selected « ^!

It has surprisingly been found that by using the inventively proposed short- and medium-chain fatty acids to achieve a higher acid number to improve the quality of the raffinate for compared to the prior art extended applications in which gloss and hardness are of crucial importance, the required amount can be significantly reduced to refining without the effect in the. It has been found that after completion of the oxidative refining and adjusting the density of the chromium-III salt solution and lowering the temperature of the reaction mixture with warm process condensate or fresh water to a temperature below the boiling point of the reaction mixture of 100 to 110 ⁰ C, the separation of lIQUID-liquid phase ready after 5 to 10 minutes is completed ·

embodiments

1. In an acid-resistant, heatable stirred tank with 10 or volume 1080 kg teilentharztes Rohmontanwacht with an acid number of 30 mg KOH / g and 120 kg of C. fatty acid (technical grade) having an acid number of 500 mg KOH / g at 100 ⁰ C.

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submitted and mixed. The acid number of the mixture is 77 mg KOH / g. The mixing ratio of raw fatty acids is 9: 1 · To carry out the oxidative refining, the mixture is mixed with 3087 1 sulfuric acid containing 600 g H ₂ SO ₄ /! contains 30 minutes at 110 to 115 ⁰ C emulsified * The oxidation solution, consisting of 1100 kg of 100 # sodium dichromate and 800 1 of water, is added within 45 minutes. In the course of a reaction time of 130 minutes, the reaction temperature of 117 ⁰ C to 125 ⁰ O increases. To adjust the density of the chromium salt solution to 1.500 to 1.600 g / ml and to cool the reaction mixture, 1000 l of hot water are added at the end of the after-reaction time. * After a very short soaking period of 10 minutes, the temperature being below the boiling point of the Reactive good, there is a sharp liquid-liquid phase separation between Rohraffinat and chrome-III-salzlbsung. Crude raffinate and chromium-III-salt solution are processed separately. While the Oehrom III salt solution is worked up in a known manner into salable chrome tannins, the crude raffinate is washed chromium-free with dilute sulfuric acid and after-perfumed with 2% sodium chlorate solution containing 250 g NaClO 2 / g. The raffinate wax yield is 93 Ma.-S ^ based on the raw montan wax-fatty acid mixture used.

Key figures of the raffinate:

Acid number: 123 mg KOH / g saponification value: 160 mg KOH / g Freezing Point: 78 ⁰ C Penetration according to TGL 12622: 14 x 1θ mm Color number according to TGL 21161: 11

By partial esterification of this raffinate with 1, 3-Butylenglykol an ester wax is obtained, which is very suitable with a residual acid number of 57 mg KOH / g for the preparation of self-gloss emulsions.

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2. According to the technological procedure according to Example 1, the following quantities of raw materials and excipients are used;

960 kg partially aerated raw montan wax 240 kg G. ₂ - Technical grade acidic acid 1100 kg 100% sodium dichromate 800 1 water to dissolve the sodium dichromate 3087 1 sulfuric acid with 600 g H ₂ SO

The mixing ratio of raw montan wax: fatty acid is 8: 2. The acid value of the mixture is 76 mg KOH / g. The raffinate wax yield is 91% by mass.

Key figures of the raffinate: 125 mg KOH / g acid number 158 mg KÖH / g saponification 78 ⁰ G Freezing point 16.10 mm Penetration according to TGL 12622 10 Color number according to TGL 21161

By partial esterification of this raffinate with 1, 3-butylene glycol, an ester wax is obtained which, with a residual acid number of 55 mg KOH / g, is very suitable for the preparation of self-gloss emulsions.

Comparative Examples

1. In an acid-resistant, heatable stirred tank with 10 volumes volume 840 kg teilentharztes raw montmic wax having the acid value 30 mg KOH / g and 360 kg of stearic acid having the acid number 200 mg KOH / g, initially charged and mixed. The mixing ratio of raw accent: C ₁ o fatty acid is 7: 3. The acid number of the mixture is 81 mg KOH / g. To carry out the oxidative refining, the mixture is emulsified with 3087 1 sulfuric acid containing 600 g H ₂ SO, / 1, 30 minutes at 110 to 115 ⁰ C. The oxidation solution, consisting of 1100 kg 100% sodium dichromate and

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800 1 of water, is added within 45 minutes. In the course of a reaction time of 130 minutes, the reaction temperature of 117 ⁰ C to 125 ⁰ C increases. For setting the density of the chromium-III-salt solution to from 1.500 to 1.600 g / ml 1000 1 heated to 80 ⁰ C water at the end of the after-reaction are supplied. After a separation time of 20 minutes, the chromium-III-salt solution and the crude raffinate are separated from each other and further processed separately. While the chromium-III salt solution is processed into salable ear tanning agents in a known manner, the crude raffinate is washed free of chromium with dilute fresh sulfuric acid and after-bleached with 2% by volume of sodium chlorate solution containing 250 g of iroloylo. The raffinate wax yield is 93 Ma .%, Based on the crude wax mixture used.

Key figures of the raffinate: 128 mg KOH / g    acid number 161 mg KOH / g saponification 76 ⁰ C Freezing point 22.10 ~ ¹ mm Penetration according to TGL 12622 10 Color number according to TGL 21161

In this, carried out in the prior art refining are added to the long-chain fatty acids in the raw clay wax, to achieve about the same acid number in the crude product mixture, the triple amount of fatty acid over the short-chain fatty acid used in Example 1 is necessary to at least twice the separation time to achieve the method according to the invention. This disadvantage can be recognized as a dilution effect on the characteristic numbers of the raffinate. The values characterizing the wax hardness, such as solidification point and penetration, are inferior to those of the raffinate of the exemplary embodiment.

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According to the technological process according to Comparative Example 1, the following amounts of crude and Hilfsatoff be used:

1080 kg partially aerated raw facial wax 120 kg stearic acid, technical grade 1100 kg 100% sodium dichromate

800 1 water 3087 1 sulfuric acid with 600 g H ₂ SO./1

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The mixing ratio of raw montan wax: fatty acid is 9: 1 · The acid value of the mixture is 47 mg KOH / g. The raffinate wax yield is 92 Ma. -% · The separation time of the liquid-liquid phase in this case is 120 minutes *

Key figures of the raffinate:

acid number 96 mg KOH / g saponification 140 mg KOH / g Freezing point 78 ⁰ C Penetration according to TGL 12622 14.10 " ¹ mm Color number according to TGL 21161 11

The disadvantage of this refinement carried out according to the known state of the art is that the liquid-liquid separation process is increased to 120 minutes when using the same amounts of long-chain fatty acid, whereby the batch run times are considerably prolonged, thus reducing the capacity of the production plant.

Claims (1)

Invented ean saying Process for the preparation of a light hard wax raffinate based on montan wax by oxidative refining of a crude product mixture with sulfuric acid and chromic acid or Alkalidichromat, characterized in that the crude product is a mixture of 70 to 95 Ma .-% of teilentarzten Rohmontanwachses and 5 to 30 Ma .- ^ a natural or synthetic, saturated or unsaturated fatty acid having a chain length of from C to C ₁₂ , or a mixture of this fatty acid is used.