SE123796C1

SE123796C1 -

Info

Publication number: SE123796C1
Authority: SE
Publication date: 1948-01-01

Description

Uppfinnare: C. Doris. Inventor: C. Doris.

Prioritet begard fra den 8 .februari 1D4ti (Frankribe). Priority requested from 8 February 1D4ti (France).

Nar man framstdRer estrar av cellulosa medelst redan kanda metoder, vid vilka den erhallna ester!' loses i forestringsblandningen, forbliva de forsta bildade mdngderna ester underkastade inverkan av reagensen, tills att all cellulosa forestrats, och utsattas pa grund darav for en viss forstorelse, som skadar beskaffenheten av den framstillIda slutprodukten. When esters of cellulose are prepared by already known methods, by which the ester obtained! ' dissolved in the esterification mixture, the first amounts formed remain subject to the action of the reagents until all cellulose is esterified, and are therefore subjected to a certain magnification which damages the nature of the final product produced.

Foreliggande uppfinning avser ett forf aringssatt for forestring av cellulosa medelst ett bad, vilket kan upplosa det erhallna eellulosaderivatet, varvid detta forfaringssatt kannetecknas daray, att i den man som cellulosaderivatet bildas och gar i losning, denna losning avskiljes fran resten av reaktionsmassan och behandlas pa sadant salt, att en vasentlig skadeverkan pa del framstailda cellulosaderivatet undgas. FOr undgaende av derma skadeverkan kan man arbeta pa varje I och f8r sig kant salt, t. ex. genom fOrstoring av overskottet pa forestringsreagens eller genom neutralisering av reaktionskatalysatorn. For utforande av det f5rfaringssatt, som utgar foremal for foreliggande uppfinning, bringas forestringsbadet i beroring med eel- som är anbragt pa en anordning, som gor det mojligt f8r lOsningen av det bildade cellulosaderivatet att passera, alit under det att de annu icke helt forestrade cellulosafibrerna kvarhallas. Dessa fibrer forbliva salunda utsatta for inverkan av reagensen, varvid fibrernas forestring fortsatter. I den man som cellulosaestern bildas, gar densamma i losning, varvid denna losning i sin tur passerar igenom anordningen och reaktionen salunda fortsatter, tills att all cellulosa forestrats. Man kan anvanda vilken.anordning som heist, som lampar sig f8r att passeras av losningen av det bildade cellulosaderivatet, t. ex. en stapel av metalltradsnat, filter av textilmaterial, som icke angripes av forestringsbadet, sandbaddar, metallspan, Raschig-ringar etc. Foreliggande uppfinning kan naturligtvis Oxen tilllampas vid saval kontinuerliga som diskontinuerliga forestringsfOrfaranden. The present invention relates to a process for the esterification of cellulose by means of a bath which can dissolve the resulting cellulose derivative, this process being characterized in that in the form and solution of the cellulose derivative which is formed, this solution is separated from the rest of the reaction mass and treated accordingly. salt, to avoid a significant adverse effect on the cellulose derivative produced. To avoid this harmful effect, you can work on each I and carry edge salt, e.g. by enlarging the excess esterification reagent or by neutralizing the reaction catalyst. In order to carry out the process which is the subject of the present invention, the esterification bath is brought into contact with electricity arranged on a device which enables the solution of the formed cellulose derivative to pass, while the not yet fully esterified cellulose fibers kvarhallas. These fibers thus remain exposed to the action of the reagents, the esterification of the fibers continuing. In the man in which the cellulose ester is formed, the same goes into solution, this solution in turn passing through the device and the reaction thus continuing until all the cellulose has been esterified. It is possible to use any device which lifts itself to pass through the solution of the cellulose derivative formed, e.g. a stack of metal wire mesh, filters of textile material not attacked by the esterification bath, sand baths, metal shavings, Raschig rings, etc. The present invention can, of course, be applied to Taurus in both continuous and discontinuous esterification processes.

I del foljande givas nagra exempel pa tilllampningen av uppfinningen utan att utgora migon begransning for densamma. I exemplen utgora delarna yiktdelar. In the following, some examples are given of the application of the invention without constituting a limitation on it. In the examples, the parts are yikt parts.

Exempel 1. 100 delar cellulosa, som underkastats vanlig forbehandling med attiksyra eller attiksyraanhydrid och eyentuellt en ringa mdngd svayelsyra, sattas till en anordning, som ãr forsedd med en lamplig omroringsanordning, tillsammans med sadana mangder attiksyra, attiksyraanhydrid och svavelsyra, att den totala blandningen innehaller 1000 delar attiksyra, 250 delar attiksyraanhydrid och 12 delar svavelsyra. Etter 45 mimiter anbringas reaktionsmassan pa ett filter, som utgores av metalltra'.dsnat och en filt av textilmaterial, som icke angripes av acetyleringsreagensen. Det bildade cellulosaacetatet gar i lOsning, och denna losning strommar igenom filtret. Till densamma saner man omedelbart en 10 ganger mindre volym vattenhaltig, 80 %-ig attiksyra, och darefter utfaller man eellulosaacetatet medelst ett start vattenoverskott. Delta acetat uppvisar utmarkta egenskaper. Sarskilt har dess losning med en koneentration ay 6i en blandning ay me- tylenklorid och alkohol en viskositet av 12 poise, Inedan ett acetat, som framstallts med samma mangder reagens men enligt de kanda forfarandena, under samma forhallanden endast har en viskositet ay 2,8 poise. Example 1. 100 parts of cellulose, which have been subjected to ordinary pretreatment with acetic acid or attic anhydride and possibly a small amount of sulfuric acid, are added to a device provided with a suitable stirring device, together with such amounts of acetic acid, acetic anhydride and sulfuric acid that the total mixture 1000 parts attic acid, 250 parts attic anhydride and 12 parts sulfuric acid. After 45 minutes, the reaction mass is applied to a filter which is made of metal wire and a felt of textile material which is not attacked by the acetylation reagent. The cellulose acetate formed goes into solution, and this solution flows through the filter. To this is immediately sanitized a 10 times smaller volume of aqueous, 80% acetic acid, and then the cellulose acetate is precipitated by means of a starting excess water. Delta acetate exhibits excellent properties. In particular, its solution having a concentration of 6 in a mixture of methylene chloride and alcohol has a viscosity of 12 poise. poise.

Exempel 2. 100 delar cellulosa, som underkastats vanlig forbehandling, forestras i ett bad, som totalt innehaller 1200 delar attiksyra, 250 delar attiksyraanhydrid, 100 delar smorsyra och 15 delar svavelsyra. Efter 40 minuters forestring infores reaktionsmassan i centrifug, vars skal Or forsedd med en mycket tat filtervavnad, som icke angripes av forestringsbadet. Den filtrerade vatskan uppsamlas och behandlas omedelbart av en 5.ttiksyrad kaliumacetatlOsning ph sa.dant salt, att svavelsyran neutraliseras och efterfoljande skadeverkan p0 det bildade aceto-butyratet undgas. Det salunda bildade aceto-butyratet Or tya. ganger viskosare On det, som skulle ha- 2— — va erhallits, om man i enlighet med den. gang-se tekniken hade drivit forestringen anda till fullstandig upplOsning av fibrerna. Example 2. 100 parts of cellulose subjected to ordinary pretreatment are esterified in a bath containing a total of 1200 parts of attic acid, 250 parts of attic acid anhydride, 100 parts of butyric acid and 15 parts of sulfuric acid. After 40 minutes of esterification, the reaction mass is introduced into a centrifuge, the shell of which is provided with a very dense filter cloth, which is not attacked by the esterification bath. The filtered liquid is collected and immediately treated with a 5.acetic acid potassium acetate solution of such a salt that the sulfuric acid is neutralized and the subsequent harmful effect on the acetobutyrate formed is avoided. The aceto-butyrate Or tya thus formed. times viscous On that which should have been obtained, if one in accordance with it. gang-se technology had driven the esterification spirit to complete dissolution of the fibers.

Exempel 3. En. kontinuerligt framstalld blandning, som innehaller 100 delar pa kant salt fOrbehandlad cellulosa, 100 delar attiksyra, 250 delar attiksyraanhydrid och 14 delk svavelsyra, underkastas till en biirjan acetylering under en tidrymd av 10 minuter i en anordning for kontinuerlig acetylering av det slag, som beskrives i det franska patentet nr 619 699. Mir fiberblandningen uttrader ur denna anordning utsaltes den for ett tryck av 45-59 kg/ cm= medelst en kolvpump och inledes i en kolonn, som innehaller en stapel av metalltradsnat med alit finare maskor, varvid de forsta hava tva maskor per cm2 och de senare 10000--12000 maskor pr cm'. Upphallstiden i kolonnen omfattar 25-av hela forest- ringstiden. Under dessa forhallanden kvarlianas de icke acetylerade fibrerna, Iran viIka avskiljes den homogena fas, som utgores av acetyleellulosalosningen i fOrestringsbadet. Desamma foras mot anordning,ens utloppsande endast i den man, som de omvandlas och uppVisas. Den littiksyrade cellulosaacetatRisning, som uttrader ur kolonnen, forsattes omedelhart med en mangd 60 %-ig attiksyra, som or lika med 1/3 av dess vikt, underkastas en kontinuerlig mogning, tills att man erhaller ett cellulosaacetat, som har en shall halt acetylgrupper, som, raknat pa attiksyran, dr ekvivalent med 55 % av cellulosaacetatets vikt, och falles medelst en stor mangd vatten. Det erhallna sekundara acetatet uppvisar, 15st i aceton till en koncentration av 6en vis- kositet av 11 poise. Om man under omriiring kontinuerligt acetylerar i en anordning utan nagon stapel av metalltradsnat och darvid reglerar anordningens gang pa sd satt, att den slutliga losningen blir fri Iran icke acetylerade fibrer, har det erhallna, sekundara acetatet endast en viskositet av 3-4 poise i 6 %-ig acetonlosning. Den for acetyleringen anvanda kolonnen kan i stallet for med metalltradsnat vara farsedd med varje slag av fyllnadskroppar med avtagande dimensioner, som kunna erbjuda fibrerna ett fortskridande kvarhallande, sasom metallspan, Raschigringar etc. Example 3. A. Continuously prepared mixture containing 100 parts of edge salt pretreated cellulose, 100 parts of acetic acid, 250 parts of acetic anhydride and 14 parts of sulfuric acid is subjected to a continuous acetylation for a period of 10 minutes in a continuous acetylation apparatus of the kind described in French Patent No. 619,699. When the fiber mixture emerges from this device, it is salted out at a pressure of 45-59 kg / cm two stitches per cm2 and the latter 10000--12000 stitches per cm '. The residence time in the column comprises 25 of the entire esterification time. Under these conditions, the non-acetylated fibers are retained, which separates the homogeneous phase formed by the acetylellulose solution in the esterification bath. They are carried towards the device, even outgoing only in the man in whom they are transformed and displayed. . which, based on the attic acid, is equivalent to 55% by weight of the cellulose acetate, and is precipitated by a large amount of water. The secondary acetate obtained has 15 pcs in acetone to a concentration of 6 and a viscosity of 11 poise. If, during stirring, continuous acetylation is carried out in a device without any stack of metal wire and thereby regulating the operation of the device in such a way that the final solution becomes free of non-acetylated fibers, the secondary acetate obtained has only a viscosity of 3-4 poise in 6 % acetone solution. The column used for the acetylation can, instead of being made of metal wire, be fitted with any kind of filler bodies with decreasing dimensions, which can offer the fibers a progressive retention, such as metal shavings, Raschigrings etc.

Exempel 4. En blandning, som kontinuerligt framstallts enligt foregaende exempel och undergatt en och samma inledande acetylering, maths medelst en pump till en eentrilag, i vilken tillforseln sker vid periferien, varvid materialets rorelse genom pumpens inverkan dr riktad mot rotation.scentrum. Under dessa forhallanden utsattas fibrerna, vilkas sp. -vikt dr av storhetsordningen 1,5, medan acetyleringsbadets icke overstiger 1,os for ett sadant kvarhallande, som forhindrar, att fibrerna bortforas samtidigt med den klara losningen, och som gör det mojligt att hell upplosa fibrerna, innan dessa liimna anordningen. &Isom en. sakerhetsatgard kan ett filter vara anbragt i den attiksyrade 18sningens utstromningsvag, men om centrifugens rotationshastighet och materialets stromningshastighet Oro lampligt valda, är denna forsiktighetsatOrd overflodig. Example 4. A mixture, which is continuously prepared according to the preceding example and has undergone one and the same initial acetylation, is fed by means of a pump to a one-layer layer, in which the supply takes place at the periphery, the movement of the material by the pump being directed towards the center of rotation. Under these conditions the fibers, the sp. weight weight of the order of magnitude 1.5, while the acetylation bath does not exceed 1, os for such retention, which prevents the fibers from being removed at the same time as the clear release, and which makes it possible to completely dissolve the fibers, before leaving the device. & Isom en. As a precautionary measure, a filter may be provided in the outflow path of the attic acid solution, but if the rotational speed of the centrifuge and the flow rate of the material are appropriately selected, this precautionary measure is superfluous.

Claims

Patent claim: Procedure for esterification of cellulose by means of a bath which can dissolve part of the obtained cellulose derivative, characterized in that in the man in which the cellulose derivative is formed and goes into the harmful effect on the produced cellulose derivative is avoided, while the reaction proceeds in the rest of the non-fully esterified mass, until all the cellulose has esterified and gone into solution. Stockholm 1949. Kungl. Boktr. IN'. A. Norstedt & SUner 450089