DE1769903A1 - Process for the production of a dispersing and wetting agent based on lignosulfonic acid - Google Patents

Description

PULP PLANT WALDHOP Mannheim, August 1st, 1968

Dr.vdB, / K.- (0.N.673)

Process for the preparation of a dispersing and Lignosulfonic acid based wetting agent.

It is known that lignin sulfonic acid and its salts are used for Belong to the group of surfactants. The interface activity results arise from the molecular structure, due to a hydrophobic, aromatic basic structure and those on its surface, hydrophilic sulfuric acid ester groups. One speaks generally also of the "sulfonic acid group" of lignin and thus of the "Lignosulfonic Acid". This has a real acid character and forms salts *

The interfacial activity of lignin sulfonic acid and its salts is largely used technically. For example, in cement production the ground mineral before burning in the so-called sludge phase by adding sodium lignosulfonate dispersed in order to save dilution water and thus thermal energy in the burning process. Even that Lignosulfonates are often added to finished cement mortars in order to achieve special effects through the dispersing effect achieve, * »B, an increase in strength or even a

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Influencing the setting time. Other significant applications The interfacial activity of the lignosulfonates is the dispersion of pigment dyes, as well as oils, fats and Waxes, of mineral oil products such as bitumen, of synthetic tanning components, etc.

The technically most important application of lignosulphonic acid or ligninsulphonates is due to their interface activity but in the field of pest control. As a natural substance without its own damaging influence on plants and animals

are these lignin compounds as dispersing and wetting agents particularly suitable. One has β.B. Wood tar or carbolineum, also produced with the addition of mineral oils as sulphite liquor dispersions and used as "seed dressing". They were also used as sprays. Other fungicides, insecticides or bactericides are lignosulphonate dispersions of nicotine as well as heavy metal salts of arsenic acid or other inorganic compounds with corresponding Properties have been offered. The so-called network sulfur, which in general, occupies a particularly large extent with 80 $ sulfur and 20 # lignosulphonate content in the fruit and Viticulture is used.

The surface-active effect of each, in technology accruing lignosulfonates is different. It turned out that the alkali salts of lignin sulfonic acid in particular

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Finally, the ammonium salt has a relatively good dispersing effect own. Partially desulphonated lignosulphonates are also used as special products for crop protection alkaline-oxidative cracking process of the sulphite waste liquor for the production of vanillin as well as alkali lignin preparations from the sulphate pulp process, in which subsequently in the sulfo acid group was introduced in a separate process became.

However, all of these dispersing and wetting agents based on lignin sulfonic acid have not always fully met the technical requirements. On the one hand, the surface activity of the simple, not specially improved lignosulfonates leaves much to be desired and they can then not compete with certain synthetic surfactants. On the other hand, the lignosulfonates are mostly too easily soluble in water, even if they have sufficient interfacial activity, so that the residence time of the active ingredients on the plants is too short, for example when dew occurs in the morning; or they are too sparingly soluble, so that the plant tissue can be damaged.

It has now been found that good surface activity of ligninsulfonic acid and ligninsulfonates with optimal adhesion of the dispersions and suspensions prepared therefrom achieved by subjecting this lignin compounds prior to their use as a surfactant of a low-temperature carbonization.

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It has been found to be particularly advantageous to use such a lignosulfonate, preferably in powder form, subjected to the smoldering, which has previously been adjusted to a pH value below 4, preferably below 3.

Lignin sulphonates are all lignin compounds produced from the sulphite waste liquor, e.g. the Ca, Na and NH salts, but also those dispersing Salts of lignin sulfonic acid, which can be obtained by reaction, e.g.

Ca salt with aluminum sulfate or with potassium carbonate or an oxalate. This is particularly suitable for the smoldering process with regard to the interface activity Mg lignin sulfonate.

The smoldering temperature should be above 150 °, preferably between 200 and 230 °. The residence times vary depending on the one used Salt of lignosulfonic acid between 10 and 100 minutes, preferably between 30 and 60 minutes in each case be carried out so that the end product of the carbonization experience a significant decrease in viscosity Has. In addition, the smoldering product should be completely sugar-free.

Example;

Magnesium lignosulfonate powder, which is obtained by atomizing a fermented sulfite waste liquor from a magnesium bisulfite digestion of beech wood and with H ₂ SO. Was adjusted to pH 2.8, was in direct contact over metal surfaces

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passed, which were heated to 220 °. The residence time was a total of 45 minutes. The smoldering gases were discharged. The weight loss of the powder was $ 18.

The color of the powder obtained had turned dark brown. The water solubility was still fully preserved; however, it was on the verge of insolubility. The total sulfur content was $ 7.2. Hexoses and pentoses were by paper chromatography no longer detectable. The viscosity of a 30% aqueous solution at 20 ° was 9.5 cP.

The test for interfacial activity was carried out using the Fischer suspension number (FSZ) method and was compared with the non-carbonized powder carried out as follows: 100 parts by weight of sulfur and 20 parts by weight of the test products (a) = untreated, b) = treated) were ground with 75 parts by weight of water for 72 hours in a ball mill. The two sulfur dispersions thus obtained were dried to a powder at 80 ° (= network sulfur),

1.25 g each of these dispersions (initial weight = X> -) were in water dissolved and the solutions were made up to 250 cm in the measuring cylinder. Then the two measuring cylinders were shaken evenly, Let rest for 5 minutes, shake again and let rest for 2 hours again. It was up to

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a remainder of 25cm lifted off. These 25cm were evaporated and balanced (yield = Y). The FSZ is calculated as follows:

FSZ. in # = 100 (1 ~ Ij

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Result;

a) In the case of unsanified lignin sulfonate, Y = 0.889; accordingly was the PSZ. at $ 29.

b) In the case of smoked lignosulfonate, Y = 0.177? accordingly was the PSZ. at 85, ι

The higher the PSZ., The higher the surface activity of the product.

Claims:

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Claims (4)

- 7 claims 1. A process for preparing a dispersing and wetting agent ligninsulfonic acid-base, characterized in that the ligninsulfonic acid or its salts are subjected to temperatures above 150 ⁰ C a carbonization. 2. The method according to claim 1, characterized in that such lignosulfonates are subjected to the smoldering process, which have previously been adjusted to a pH value below 4, preferably below 3. 3. The method according to claims 1 and 2, characterized in that that the smoldering at temperatures between 200 and 230 ° and with residence times of more than 10 minutes, preferably between 30 and 60 minutes. 4. Process according to claims 1 to 3, characterized in that the carbonization of the lignosulfonic acid or its Salts is carried out until the reaction product is sugar-free. 109829/1953 ^c % ®Nal / w.