Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/12—Powdering or granulating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
  • B01J20/24—Naturally occurring macromolecular compounds, e.g. humic acids or their derivatives
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
  • C08B16/00—Regeneration of cellulose
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/12—Powdering or granulating
  • C08J3/16—Powdering or granulating by coagulating dispersions
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
  • C08J2301/02—Cellulose; Modified cellulose

Definitions

• the object of the invention is to provide a process and apparatus for producing from cellulose solution pearls with microporous structure and high adsorptive surface.
• the ideal adsorbent is spherical.
• the cellulose pearl adsorbent it is applicable first of all as microcapsule. With appropriate. fillers the field of application of cellulose pearl is extended.
• the product has excellent properties: e.g. it is acid-proof, alkali-proof and solvent-resistant. As a result of its advantageous properties it may be used for cleaning antibiotics in case of fermentation, cleaning nucleic acids, extracting natural dyestuffs, recovering valuable components of waste waters, purifying sewages, removing organic impurities, blotting off plant protectives and plant nutritives.
• the pearl is formed from viscous solution by passing the latter through a bore with high speed, the coagulation is carried out in spinning bath.
• traditional apparatus is used for realizing the process.
• the starting material is cellulose solution
• organic solvent is used for preparing a suspension which is precipitated in an acid solution.
• CS-2 858-74, DE-2 523 893 and US-4 055 510 a suspension is prepared from viscous solution in non-aqueous medium.
• Epichlorohydrin is used for modifying the final product and the precipitation is carried out with an acid solution.
• adsorptive powders are also used as additives for improving the adsorptive characteristics of the cellulose pearl or for developing the selective adsorptive capacity.
• Such a process is described in patent specifications Nos. CH-625 716 and IT-50-20381.
• hydrophilic polymers are used as mixing component according to the patent specification No. DD-206 679.
• the process is regarded as important and usually existing machinery is used: only in one case is the pearl forming bore system combined with vibration.
• the cellulose pearls formed in the known way have a structure where there is an outer layer and within a filling of cellulose gel and adsorptive powder.
• this structure reduces the adsorptive capacity. Therefore it is an aim of the invention to produce such cellulose pearls which have, owing to their structure, higher adsorptive capacity than the products known at present.
• the process of the invention relates thus to the production of cellulose pearls of porous structure and of high adsorptive capacity and differs from the previously described processes in that bubbling and foam-forming agents are used for the pearl formation and for the aftertreatment. It has been found that pearls of fundamentally different structure may be formed as compared to the known processes. This new structure ensures unexpected surplus actions of which good use may be made when applying the product.
• the foam-forming agent is mixed into a solution of cellulose or of a cellulose derivative, such as cellulose xanthogenate, which solution is dropped in the precipitating bath through an opening of preferably 1-10 mm diameter.
• the viscosity of the cellulose solution is preferably 200-10.000 mPs.
• the employed foamforming agents are gases, such as N 2 , O 2 , NH 3 , air,N 2 O, hydrogen, acetylene, etc., carbonates, preferably Na 2 CO 3, ZnCO 3 or (NH 4 ) 2 CO 3, calcium and magnesium carbonate.
• the viscous solution may contain fillers as well.
• the CO 2 , SO 2 , CS 2, O 2 , H 2 , C 2 H 2 , N 2 , N 2 O, NH 3 gases formed on the surface and in the interior of the drops bring about "hollows" in the pearl.
• the structure of the pearl obtained in this way differs from that of the usual pearl, since its surface is faveolate and porous and its cross-section contains hollows and channels. This difference in structure may be observed on electron microscopic pictures.
• the acidic precipitating bath can be e.g. 2-6 N acid solution (preferably sulfuric acid) containing 50-200 g/cm 3 of sodium sulfate as well.
• the influencing of the cellulose xanthogenate decomposition, the releasing speed of developing carbon bisulfide steams, as well as the bubbling agents charged in the viscous solution play an important part.
• the decomposition products of materials of different half-life appear with a time-lag during the production, thus the gaseous products of the simultaneous reactions facilitate the development of channels.
• the decomposition products of the gas-forming materials quicken the formation of the cellulose skeleton.
• the process of the invention aiming at producing cellulose pearls gives the positive results of the known processes and shows surplus action as compared to them, which manifest themselves first of all in the modification of the structure of the pearls.
• an outer layer is developed within which a filling of cellulose gel or adsorptive powder can be found.
• the foamed pearl produced according to the process of the invention has, however, a spongy structure on the large surface of which the adsorbents are set easily. These phenomena can be seen on electron microscopic pictures.
• the foam-forming material has no detrimental effect on the properties of the additives, it even increases their action.
• Usual fillers such as active carbon, silica-gel, zeolite, bentonite, ion-exchange resin, bone coal, alumina silica gel, polymer powders (CMG, sodium alginate, hydroxyethyl cellulose, poly/vinyl alcohol/, poly/acryl nitrile/), etc., can be used also in case of the process of the invention.
• the process for producing the foamed pearls of the in vention enables a very advantageous version of the silica gel pearls to be formed.
• silica gel powder is mixed in the viscous solution to give the pearl.
• the grain size of silica gel, the homogeneity of the viscous solution and the conditions of precipitation determine the arrangement of silica gel in the interior of the pearl.
• silica gel is not mixed in the viscous solution but it is formed simultaneously with the formation of the pearl, it covers the wall of the pearl's spaces in a very fine layer. This may be achieved by precipitating silica gel on the pearl's wall.
• Pearls with new properties may be produced furthermore by utilizing humic acids.
• Humic acid is formed in the system by charging humates.
• Chilorophyll and cyclodextrin may also be incorporated into the pearl.
• Advantageous pearl of good practical value may be obtained by using magnetic iron oxide (magne t i t e ) a s f i l le r wh ich keep s it s ac t iv i t y in t he ce l lu los e pearls, too.
• Activated red mud may also be used.
• Polymer powder additives may be besides the known ones: polyamide, polypropylene, polyethylene. Also incorporated may be sulfur, solid or liquid plant protectives which are water-insoluble.
• Figures 1-6 are electron microscopic pictures and serve to illustrate the structure
• Figure 7 is a sketch of the apparatus of the invention.
• Figures 1 and 2 show that without foaming a relatively smooth surface, glass free from pores and channels is formed.
• Figures 3 and 4 show that the surface of the product manufactured by the process and apparatus of the invention is broken, faveolate and contains numerous pores.
• This structure may be changed according to the aim of the application, by influencing the technology.
• This kind of pearl absorbs solutions from its environment and releases them in unchanged condition. Thereby it ensures an ideal component transport.
• the novelty of the solution of the invention consists in that the desired result is achieved by the technological steps ensuring the new properties together with special machinery.
• special static stirrer is used for mixing the additives.
• the bearing pressure of the drop-forming die is preferably 1-10 bars.
• the coagulation time is set preferably by a tilting edge from plastic and the coagulate is separated from the acid for instance by a net separator.
• the raw product may be forwarded by liquid injector, a secondary coagulation bath may serve to operate the injector.
• the secondary coagulation is carried out preferably under reduced pressure.
• the angle of inclination of which may usual ly change between 0 and 90 and in which the flow direction of the individual cycles is variable: the treating fluid may be circulated alternately in un if low or in counterflow.
• Drying is performed preferably at 60-150 C for 1-20 hours.
• the drying rate and the speed of releasing the steam from the inner structure contribute also to the formation of a favourable structure.
• the novelty of the invention lies furthermore in that a production line of industrial scale has been created from apparatuses which have not yet been used for similar purposes, thus an extremely economic solution is provided.
• the cellulose solution (preferably viscous) intended for use is filled in A stirring recipient, then the bubbling material prepared in 9 anterior recipient is added.
• the bubbling material may be a real solution or suspension, but may contain gas bubbles as well.
• the viscous solution After mixing the 1 viscous solution and 2 additives (solid powders, solutions, crosslinking agents, etc.), as well as the bubbling material, the viscous solution passes through B static stirrer (intensive homogenization) and reaches the drop-forming die.
• the C drop-forming die contains elastic drop-forming elements of low friction coefficient produced by special plastic shaping technique; this solution makes it possible to produce 1.000-100.000 drops/sec.
• the viscous solution gets to the coagulation bath in the form of drops.
• the pre-coagulation takes place and the formation of the porous structure begins.
• the continuous transport is achieved by adjusting the flow rate and flow direction of the coagulation bath, the level control and continuous taking away of the product are ensured by the suitably developed oblique tilting edge.
• the distance between the drop-forming die and coagulation bath - i.e. the free path length of drops - is adjustable.
• the net separator inserted between the D and E apparatuses is intended for separating the cellulose pearl from the coagulating fluid, which fluid is returned into the circulation system.
• the net separator is a so-called reinforced plastic grate formed by hyperbola-type tracing, which grate is - s een from the side of the product's flow - a diamond shaped plastic net including an angle of 60 and having an edge distance of 2 mm and is reinforced on the back side by a hexagon supporting grate having an edge distance of 25 mm.
• the two types of grates are fastened together by heat treatment. It is in the E secondary coagulation apparatus that the cellulose skeleton is developed, the foaming reaction and the formation of the porous structure are continued.
• This apparatus may be barometric, preferably it is operated, however, at a reduced pressure.
• the product is passed in the G aftertreating reactor by jet injector.
• This process also contributes to the formation of the channel structure.
• the G apparatus is a contact fluid reactor, the angle of inclination of which is variable between 0-90°, furthermore, the flow direction of the treating solutions may be changed in the individual cycles.
• the product obtained by the aftertreatment passes from the G apparatus in the H drier. This dier ensures a very intensive mixing which makes possible a quick release of water.
• the quick removal of water from the inner hollows is the final step in the formation of the porous channel system.
• Example 3 To the viscous solution, the composition and quantity of which is given in Example 1, 50 kgs of ZnCO 3 are mixed; the pearl is formed from this solution. Precipitation and aftertreatment are the same as in Example 1. Example 3
• Example 4 120 kgs of Na 2 CO 3 and 140 kgs of active carbon are mixed, with a static stirrer.
• the formation of pearl is carried out according to Example 1.
• Cellulose pearls are obtainedwhich are filled up with active carbon and have a good adsorptive capacity.
• the dropping apparatus operates at a pressure of 2 bars, the coagulating acid level is ensured by means of a tilting edge, the constant removal of the pearls formed continuously is also arranged.
• Example 4

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Analytical Chemistry (AREA)
• Dispersion Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Biochemistry (AREA)
• Materials Engineering (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)

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• 1989
  • 1989-06-30 EP EP19890907252 patent/EP0430952A1/de not_active Withdrawn
  • 1989-06-30 WO PCT/HU1989/000033 patent/WO1991000142A1/en not_active Application Discontinuation

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