GB652543A - Improvements in the manufacture of cellulose esters - Google Patents
Improvements in the manufacture of cellulose estersInfo
- Publication number
- GB652543A GB652543A GB21813/48A GB2181348A GB652543A GB 652543 A GB652543 A GB 652543A GB 21813/48 A GB21813/48 A GB 21813/48A GB 2181348 A GB2181348 A GB 2181348A GB 652543 A GB652543 A GB 652543A
- Authority
- GB
- United Kingdom
- Prior art keywords
- temperature
- cellulose
- allowed
- rise
- acid
- 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
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
Cellulose is esterified with the anhydride of an aliphatic acid having 2-4 carbon atoms in the molecule in presence of enough of an aliphatic acid of 2-4 carbon atoms to dissolve the cellulose ester formed and in presence of an inorganic acid-reacting catalyst; the cellulose is mixed with all the anhydride to be used and with the solvent acid and catalyst; the temperature is maintained below 40 DEG C. until considerably more than half the cellulose has dissolved as ester and the rate of reaction has greatly decreased; and the temperature is then raised or allowed to rise above 40 DEG C. and so maintained until esterification is substantially complete. Preferably the temperature is initially allowed to rise rapidly to a maximum between 20 DEG and 40 DEG C. and kept at this maximum until considerably more than half the cellulose has dissolved as ester. It is then raised to 40-60 DEG C. for the remainder of the reaction. For high viscosity cellulose acetate the greater part of the esterification may take place at a temperature rising to a maximum of 20-25 DEG C. When esterification is complete and substantially no undissolved fibres remain, the cellulose ester may be hydrolysed while in solution until it has solubility in acetone. In an example, cellulose is pretreated at 25 DEG C. with a mixture of sulphuric acid, water, and glacial acetic acid. It is then acetylated with a mixture of acetic anhydride, glacial acetic acid, and sulphuric acid which has been cooled to 5 DEG C. The temperature is allowed to rise to 25 DEG C. and is maintained at this temperature for 40 minutes. The temperature is then allowed to rise to 42 DEG C. and maintained at this temperature for 29 minutes. Water is added and part of the sulphuric acid is neutralized, after which the cellulose acetate is ripened until it has an acetyl value calculated as acetic acid of 56 per cent. In another example, the temperature is allowed to rise to 25 DEG C. in the first stage and afterwards allowed to rise to 43 DEG C.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US652543XA | 1947-08-28 | 1947-08-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB652543A true GB652543A (en) | 1951-04-25 |
Family
ID=22061415
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB21813/48A Expired GB652543A (en) | 1947-08-28 | 1948-08-18 | Improvements in the manufacture of cellulose esters |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB652543A (en) |
-
1948
- 1948-08-18 GB GB21813/48A patent/GB652543A/en not_active Expired
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