SU823385A1 - Method of cellulose acetate production - Google Patents

Description

 -one ,

This invention relates to the production of secondary cellulose acetates, in particular thermostable, used to produce plastics.

A method is known for producing low-substituted cellulose cellulose by dissolving cellulose acetate for fiber in glacial acetic acid, followed by hydrolysis in acetic acid and isolating the crude product, washing and drying it. This method involves the recycling of waste cellulose acetate acetate for fiber, which has an associated acid vinegar content of 53.7-54.9%, into cellulose acetate with an acetic acid content of 45-46.5%.

However, this method is ineffective since low-produced cellulose acetate is produced in small quantities (2–3 tons per year}, and because of this it is impossible to recycle all cellulose wastes obtained from large-scale production. Stage of the dead wood waste (requires additional consumption of solvent and takes a long time (5-7 hours). In addition, using this method it is impossible to get half a ton.

thermostable cellulose acetate with a content of bound acetic acid of 50-54% due to the absence of a stage of viscosity reduction and bleaching, and also the presence of a hydrolysis stage.

The purpose of the invention is to obtain thermostatic cellulose acetates.

This goal is achieved by the fact that in the method of producing acetone E of cellulose using cellulose acetate production waste, the waste is mixed with water, c. the resulting suspension is added with an aqueous solution of sulfuric acid containing 1.4-7 / 32 parts by weight of sulfuric acid per 100 weight. hours of waste and 0.61, 5 weight. h. aa 100 weight. including waste potassium permanganate, and incubated at 35-42 seconds, followed by washing and drying the target product.

Soak: Waste in water or weak acetic acid creates more favorable conditions for further processing.

Sulfuric acid has a swelling effect on keratinized cellulose acetate waste, which creates more favorable conditions for efficient treatment of potassium permanganate. In addition, sulfuric acid contributes to the specific viscosity of the finished product, in view of the fact that cellulose acetate acetate for fiber has different specific viscosity, in most cases exceeding the specific viscosity of thermostable acetals of cellulose, to reduce its amount of sulfuric acid. acids and time of processing, waste solution containing sulfuric acid and potassium permanganate.

The proposed method allows iz-z waste cellulose acetate for the neck to obtain thermostable acetatat cellulose for plastics with the best indicators,

Example 1. 100 g of waste acetylcellulose for fiber (sp. In s 0.5) are soaked in 1 liter of water -. The resulting α-suspension is treated with an aqueous solution containing .7.32 wt. HgSOj, per 100 weight.h. acetate, cellulose, with the simultaneous addition of 23 ml of 5% KM, | O4 for 60 min at 35 ° G. The bleached cellulose acetate was washed three times with water, and 142 ml of 5% oxalic acid was added to the suspension. The treatment is carried out for 3 hours at 60-65 C. The thermostable cellulose acetate obtained after bleaching is washed only with water for an hour to r.h. 0, then for 3 hours, they are washed three times with water with the addition of CdO, in order to ensure a hardness of 1.5. .

 2. 100 g of waste acetylcellulose with a specific viscosity of 0.47 is soaked in 1 liter of water. The resulting suspension is treated with an aqueous solution containing 5-, 3 parts by weight per 100 parts by weight, cellulose acetate for 30 minutes at, then 23 MP of 5% KMn04 are added and the treatment is continued for another 30 minutes. Further processing, washing and testing of the obtained samples are carried out according to Example 1.

Example 3. 100 g of cellulose acetate waste with a specific viscosity of 0.47 are soaked in 1 liter of water. The resulting suspension is treated with an aqueous solution containing .5.3 parts by weight of H2504 per 100 weight. including cellulose acetate, for 15 min at. Then, after 15 minutes, 23 ml of KMbO are added to the suspension and the treatment is continued for another 45 minutes. Further processing, washing and testing are carried out as in Example 1.

Example 4. 100 g waste cellulose acetate for a fiber with a specific viscosity of 0.45 is soaked in 1 liter of water. The resulting suspension is treated with a solution containing:; 1.4 weight by weight h. Hj2SO4 per 100 weight. including cellulose aceuate with the simultaneous addition of 23 ml of KMpOd. Further processing, washing and testing are carried out as in Example 1-.

PRI me R 5 (control). 100 g waste cellulose dl. fibers with a specific viscosity of 0.5 are treated, washed and dried in example 1, but without the addition of sulfuric acid.

Table 1 presents the properties of cellulose wastes.

vre- men

0.5

7.32

same 7.32

0.5 7.32

At the same time

60 60 60

0.425 0.344 8 0.42 0.34 V, 2 0.427 0.34 7.9

5.3

b 0.475.3

5.3

5.3

5.3

b 0.475.3

5.3

.5,3

a 0.45 1.4

1.4 1.4 1.4

600,430,347

606,4290,3457

600,4290,3397,5

600,430,347,4

45

0.435 0.3457.2

45

0.437 0.3467.4

45

0.432 0.3457.2

0.436 0.3477.3

45

3Q0,420,35.8

300,4150,349 8.5

300,420.35 8.7

300,420,348 8 From the table. It can be seen that the addition to the solution for treating the waste of HaSO can reduce the specific viscosity of the product obtained and thereby increase its thermal stability. The thermostability of celksozy acetate is determined by the color of the heated disc according to a selected scale. The lower the color of the heated disc, the. higher thermal stability of the product. TkaEoothod6v without sulfuric acid for 60 minutes (example 5, not as good / short results, so KajK; bip HraHaT potassium during this time could not penetrate into the atmosphere and waste particles without their preliminary swelling. Proposed The method of obtaining cellulose acetates will shorten the processing time of waste and obtain thermostable cellulose acetates on their basis.

Claims (1)

Continuation of the Table The claims of the method for producing cellulose acetates using waste products for producing cellulose acetates, characterized in that, in order to obtain thermostable atieTaTOB cellulose, waste is mixed with water, an aqueous solution of sulfuric acid containing 1,4- is added to the resulting suspension. 7.32 parts by weight, sulfuric acid and 100 parts by weight waste and 0.6-1.5 weight.h. per 100 weight parts potassium permanganate waste, and incubated for 30-60 min at 35g-42 C, followed by washing and drying the target product. Sources of information taken by eo attention during the examination 1. USSR author's certificate No. 213794, cl. From 08 To 3/06, 1964 / (prototype).