SU511325A1 - Composition for washing the hydroxyethyl cellulose - Google Patents

Description

(54) COMPOSITION FOR HPOMUBIOL OXYETH; SCRIPTURE

one

The invention relates to a process for the preparation of cellulose ethers, in particular, water soluble (oxyethylcellulose (GEC).,

A known composition for industrial akskatshashpulpyu, compositions of acetsh, water in benzoic acid. This composition cannot be used when receiving oxychelcellulose according to a continuous scheme in connection with the necessity of 3-fold intermediate processing operations of the obtained product.

 To increase the degree of purification of oxystilcellulose, to carry out the process according to a non-invasive scheme, and to reduce the solvent consumption during washing, a composition is proposed for washing water-soluble hydroxycellulose after alkylation,. consisting of 37.2-47.5% by weight of acetone, 37.3-47.4% by weight of methanol, 0.4-0.05% by weight of sodium sulphate and water (the rest). After passing the mixture through the product to be purified, it is neutralized with sulfuric acid, the sodium sulphate precipitate is filtered off, 20-30% of the filtrate is sent for rectification, 70-80% is fortified with a mixture of lower alcohols and lower ketones and again sent to the purification stage.

Methanol and acetone are preferably used as lower alcohols and lower kegs, and methanol: acetone: water:; sodium sulfate. Select the following percentage (weight) ratio of 35-48: 35-48:; 4-30: O, I-0.6, respectively.

It is desirable to obtain this washing mixture by washing the oxystilcellulose after synthesis with a mixture of lower alcohols and a lower keta, for example, methanol and acetone in the ratio I: 1, followed by 11e n: ralisation with its seriobic acid and direction; operation until the content of the component in the wash mixture reaches the specified limit.

In the proposed method, an alkaline delulose containing 14-15% alkali, 40-45% water, 41-45% cellulose, is treated with ethylene oxide to obtain a water-soluble product. The caustic cellulose containing, after the synthesis, alkali, water and other reaction products, is subjected to purification according to a continuous countercurrent scheme. A mixture of organic solvents, for example a mixture of methanol: acetone in a 1: 1 ratio, is fed in countercurrent to the movement of hydroxyethylcellulose. After a single use, the washing mixture containing, in addition to methanol and acetone up to 1.3% 1%, up to 4%, is neutralized with sulfuric acid with a concentration of 70-80%, the sodium sulfate precipitate is filtered off, while a small part of sodium sulfate (up to 0, 1%) remains in dissolved form in the rinse mixture. The filtrate, containing methanol, acetone, up to 5 Bes.% Of water and up to 0.1 weight of sodium sulfate, is sent back to the purification stage. This operation is repeated until the industrial mixture fed to the bulk stage contains 30% water and up to 0.5% sodium sulfate. It was established that with this water content, the water-soluble hydroxyethyl cellulose dissolves and partially dissolves, so after separating from the washing smelting plant by neutralizing with sulfuric acid and filtering the precipitate, it is divided into two parts: one part (up to 25%) of naira is on rectification, and the second part (up to 75%) is strengthened with a fresh mixture of organic solvents to contain 23–27 wt.% water, preferably 25 wt.%, in it, and is sent to the cleaning flock. At the same time, the industrial mixture contains 0.4–0.5 Bes.% Sodium sulfate. .The process is continued at a constant working X: Bench, which consists in the fact that the purification of water-soluble hydroxyegylcellulose is carried out with an industrial mixture: acetone: water as a percentage (by weight) of 37.5: 37.5: 25 in the presence of 0.4-0 , 5 wt.% Sodium sulfate. After each a & Organic solvent consumption at the purification stage, t / t of hydroxyethylcellulose

The amount of rectified blend mixture, t / t hydroxyethylcellulose

Losses during cleaning (by weight of the finished product),%

The ash content in the purified OEC counting on sodium sulfate,%

Example. Hydroxyethyl cellose containing 10% caustic soda, 30% water and other reaction products is cleaned in an uninterrupted counter-current manner with a mixture of 50 wt.% Methanol and 50 wt.% Acetone with a mixing ratio of 1: 10 oxyethyl cellulose. containing 1.3% sodium hydroxide and 2% water, neutralized with 70% sulfuric acid, the sodium sulfate precipitate is filtered off and the filtrate, containing 4% by weight of water, 0.1% by weight of sugar, 13

8.5

3.5

sodium fata, again sent for purification of oxystilcellulose by the oxymethyl method.

As a result of 4-fold use and neutralization, the mixture after separation of sodium sulfate by filtration consists of 18% by weight of water, 0.3% by weight of sodium sulfate, 40.8% by weight of acetone and 40.9% by weight of methanol. Next, 25% of the filtrate is taken for rectification, and a fresh mixture of 50% by weight of methanol and 50 Bes.% Of acetone is added to the remaining part equal to the amount selected for the rectification of these estimates through the product being cleaned and neutralized with 70-80% ferrous acid and filtration, the filtrate is divided into parts: one part (20-30%) is sent for distillation, another (70-80%) is fixed with a fresh mixture of organic solvents to the specified water content and sent to the purification step. The proposed method can be carried out ne {zhodaches |; and. The proposed method allows to reduce the consumption of organic solvents for the purification of water-soluble hydroxyethylcellulose by replacing part of them with water. This is made possible by introducing a small amount of sodium sulphate into the industrial mixture, which prevents the water-soluble oxystilcellulose from dissolving and dissolving into the industrial mixture. The method also makes it possible to reduce the amount of liquid liquid going for rectification, due to the fact that the combined method of regeneration of the industrial mixture is applied: the alkali is removed by sedimentation and filtration, on reductmate | ayia, it is not the whole volume of the mixture that is affected, but the linear - as part of the water present in the blend mixture, is used as a component of the mixture used for the purification of oxystilcellulose. The content of sodium sulfate in the finished product does not exceed the permissible. Characteristics of the proposed process are shown in the table.

ation. The mixture thus strengthened containing 15% by weight of water and 0.3% by weight of sodium sulphate is sent back to purification (ls ethyl cellulose by the method described. Washed and dried oxnethylcellulose contains 3.4% ash (calculated on sodium sulphate). 8% by weight of the final product.

PRI mme R 2. Cis (ethylcellulose, the composition of which is indicated in Example 1, is purified with a mixture of 50 wt.% Methanol, 50 wt.% Acetone, but the wash mixture is used once. As a result of the single use and neutralization of the bulk after filtration contains 47.5% by weight of acetone with 47.4% by weight of methanol, 5% by weight of water and 0.1% by weight of sodium sulfate. This mixture is washed with oxyl methylcellulose of the same composition as described in Example 1. Washed and dried hydroxyethylcellulose contains 4% ash (counting and sodium sulphate). Loss during cleaning is 5% by weight of the final of the product.

PRI me R 3. Oxyethylcellulose, the composition of which is indicated in Example 1, is cleaned with a mixture of 50 wt.% Methairl and 50 wt.% Acetone, but the wash mixture is used 6 times. As a result of six times neutralization, the mixture after the filter contains 34.7% by weight of water. Next, 25% of the weight of the mixture is taken for rectification, and a fresh mixture containing 50% by weight of methanol and 50% by weight of acetone in an amount equal to that selected for rectification is added to the remaining part. The resulting industrial composition

containing 25% by weight of water, 37.2% by weight of acetone, 37.3% by weight of methanol and 0.5% by weight of HaTjHia sulphate, is sent to the washing with hydroxyethylcellulose using the method described in Example 1.

Pressed and dried hydroxyethylcellulose contains 2.8% ash. The cleaning loss is 8.5% by weight of the final product.

Example 4, In a jar with a gots mixer, wash the mixture of the composition, wt. %:

40.8 40.8 0.4 18 are washed with hydroxyethyl ldallulose until the ash content is 4%. The cleaning loss is 5%. ..

Claims (1)

Invention Formula Composition for oxime cellulose posilkillers, containing water and acetone, characterized in that, in order to reduce solvent consumption during washing, the composition additionally contains sodium sulfate and methanol when the ratio of components, wt.%: Acetone37,2-47,5 Methanol37,3-47,4 Sodium sulfate 0.4-0.5 Water the rest.