GB693699A - Improvements in and relating to the production of cellulose esters - Google Patents
Improvements in and relating to the production of cellulose estersInfo
- Publication number
- GB693699A GB693699A GB1940750A GB1940750A GB693699A GB 693699 A GB693699 A GB 693699A GB 1940750 A GB1940750 A GB 1940750A GB 1940750 A GB1940750 A GB 1940750A GB 693699 A GB693699 A GB 693699A
- Authority
- GB
- United Kingdom
- Prior art keywords
- temperature
- weight
- acid
- per cent
- sodium chlorite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
- C08B3/00—Preparation of cellulose esters of organic acids
- C08B3/22—Post-esterification treatments, including purification
- C08B3/30—Stabilising
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Biochemistry (AREA)
- Materials Engineering (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
A precipitated secondary cellulose ester, e.g. cellulose acetate, is stabilized by treating it with a dilute aqueous solution of a mineral acid at a temperature not less than 70 DEG C. and, either simultaneously with or subsequently to the stabilizing treatment, it is bleached by treating it with an aqueous sodium chlorite solution in presence of acid. Sulphuric acid is the preferred mineral acid, and a solution containing 0.02-0.10 per cent by weight of sulphuric acid may be used. The proportion of sodium chlorite used may be 0.1-2.5 per cent by weight based on the weight of the cellulose ester. The stabilizing treatment may be carried out at 125-150 DEG C. under superatmospheric pressure. When the bleaching is carried out separately from the stabilization, the temperature of bleaching may be 70-100 DEG C. at atmospheric pressure. The treated cellulose esters may be moulded into crystal-clear articles of good heat stability. In an example, freshly-precipitated cellulose acetate flakes are washed until the free acetic acid content is reduced to 0.02 per cent. The flakes, suspended in 10 times their weight of wash liquor, are pumped into a pressure vessel and the temperature is raised by live steam to 90 DEG C. Small proportions of sulphuric acid and sodium chlorite are added and then the slurry is heated to 140 DEG C. and maintained at this temperature for 30 minutes. The pressure is then released and the product is washed and dried. U.S.A. Specifications 1,948,517, 2,135,980 and French Specification 915,740 are referred to.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1940750A GB693699A (en) | 1950-08-03 | 1950-08-03 | Improvements in and relating to the production of cellulose esters |
ES0198800A ES198800A1 (en) | 1950-08-03 | 1951-07-14 | IMPROVEMENTS IN THE MANUFACTURE OF CELLULOSE ESTERS |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1940750A GB693699A (en) | 1950-08-03 | 1950-08-03 | Improvements in and relating to the production of cellulose esters |
Publications (1)
Publication Number | Publication Date |
---|---|
GB693699A true GB693699A (en) | 1953-07-08 |
Family
ID=10128846
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1940750A Expired GB693699A (en) | 1950-08-03 | 1950-08-03 | Improvements in and relating to the production of cellulose esters |
Country Status (2)
Country | Link |
---|---|
ES (1) | ES198800A1 (en) |
GB (1) | GB693699A (en) |
-
1950
- 1950-08-03 GB GB1940750A patent/GB693699A/en not_active Expired
-
1951
- 1951-07-14 ES ES0198800A patent/ES198800A1/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
ES198800A1 (en) | 1953-08-16 |
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