CN1548460A - Dry hydroxyalkyl starch producing process - Google Patents
Dry hydroxyalkyl starch producing process Download PDFInfo
- Publication number
- CN1548460A CN1548460A CNA031183980A CN03118398A CN1548460A CN 1548460 A CN1548460 A CN 1548460A CN A031183980 A CNA031183980 A CN A031183980A CN 03118398 A CN03118398 A CN 03118398A CN 1548460 A CN1548460 A CN 1548460A
- Authority
- CN
- China
- Prior art keywords
- starch
- dry method
- production process
- hydroxyalkyl starch
- method production
- 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.)
- Pending
Links
Landscapes
- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
The present invention relates to dry hydroxyalkyl starch producing process. Starch and alkyl epoxy compound are synthesized directly inside a kneading reactor under the action of small amount of organic dispersant and in the presence of alkali catalyst. The present invention has high product quality and the substitution degree MS of the hydroxyalkyl starch product may be regulated in relatively large range according to different uses.
Description
Technical field
The present invention relates to a kind of hydroxyalkyl starch dry method production process.
Background technology
Hydroxyalkyl starch (Hydroxyalkyl Starch), particularly hydroxypropylated starch (Hydroxypropyl Starch) and hydroxyethylamyle (Hydroxyethyl Starch) are the important kinds of a class in numerous modified starches, since the forties in last century, many in the world countries all have the people this to be done a large amount of research and developments.Development in recent years shows that hydroxypropylated starch is especially significant.
Hydroxypropylated starch belongs to non-ionic type, and it is high to replace ehter bond stability, in hydrolysis, and oxidation, the crosslinked not easy fracture of ehter bond that waits in the chemical reaction process.The hydroxypropylated starch of certain substitution value has good wetting ability, and it is high that it sticks with paste liquid stability, good fluidity, and a little less than the retrogradation, so hydroxypropylated starch is in foodstuffs industry, oil field industry, paper industry, fields such as textile industry have obtained using widely.
Research and development through decades, the hydroxyalkyl starch production technique has many kinds, summarize and get up to have the starch milk wet method, non-aqueous solvent method and dry method three major types, wherein the starch milk wet method is most representative a kind of in current each production technique of the hydroxyalkyl starch of production both at home and abroad.The main points of this method are that starch is made into the 30-40% emulsion, for preventing starch granules swelling in water, need to add the sodium sulfate of dry starch weight 5-10%, the sodium hydroxide that adds dry starch weight 1-3% again, the propylene oxide that under brute force stirs, adds reacting weight, closed reactor, under 35-50 ℃ of temperature, reaction 8-24hrs.After reaction was finished, reactant filtered through neutralization, washing, and drying promptly becomes product after the pulverizing.This production technique is simple, and is not high to equipment requirements, constant product quality, and color and luster is good, but its shortcoming is the product that can not prepare high substitution value, thereby be restricted in the application of many industrial circles.Non-aqueous solvent method promptly is that starch is scattered in the non-aqueous solvent, and non-aqueous solvent commonly used has methyl alcohol, ethanol, Virahol, acetone, benzene class, hydro carbons etc., wherein best with the Virahol effect, under agitation add basic catalyst then, as sodium hydroxide, potassium hydroxide, yellow soda ash etc. add propylene oxide then.After reaction finishes, through neutralization, remove and desolvate, washing is filtered, and drying is pulverized, and screening etc. promptly obtains product.The great advantage of this method be can prepare the bigger product of substitution value and yield higher.But the non-aqueous solvent costliness is inflammable, and some has certain toxicity, the production cost height.The preparation technology's method and the U.S.Pat.4 of the disclosed high substitution value hydroxypropyl starch of Chinese patent application CN1175587A, 451, the preparation technology of 649 hydroxypropylated starchs that disclose all is the methods that prepare the high substitution value product under a large amount of excessive situations of propylene oxide, because of relating to the recovery of propylene oxide, it is uneconomical unsafe implementing on the actual industrial production.
Dry technology for production be starch with particle form in the presence of a spot of water and catalyzer, under certain temperature and pressure, generate hydroxypropylated starch with the propylene oxide direct reaction, the water yield commonly used is generally the 5-20% of dry starch weight, catalyzer commonly used has alkali, phosphoric acid salt, vitriol, carboxylate salt, amines etc., wherein bases is the most commonly used.Concrete grammar is that ative starch is directly put into reactor, and moisture content is adjusted to requirement, the levigated catalyzer is dropped into again, use the nitrogen replacement reactor, add propylene oxide at last, at temperature 80-90 ℃, under the reaction conditions of pressure 0.2-0.5Mpa, reaction 3-8hrs.The major advantage of this method is that technological process is simple, can prepare hydroxypropylated starch than high substitution value, production cost is lower, but it is generally acknowledged that dry technology for production is because of propylene oxide easy polymerization reaction take place under High Temperature High Pressure and base catalysis, the product purification difficult, propylene oxide belongs to flammable and explosive substance again, so be difficult to industrialization.
In numerous United States Patent (USP)s, there are many patents to relate to and prepare hydroxypropylated starch with dry process, as U.S.Pat.2,516,634 methods that disclose are (as sodium-chlor with water soluble alkali and a small amount of salt, sodium sulfate etc.) make catalyzer, starch keeps moisture content about 10%, be equipped with stir and the voltage-resistant reactor of temperature-control device in it is stirred, under partial vacuum, import etherifying agent on a small quantity (as oxyethane in batches, propylene oxide), at pressure 10-15p.s.i.g. (0.07-0.11Mpa), under the temperature 160 (71 ℃), reaction 5-10hrs. promptly makes hydroxypropylated starch.U.S.Pat.2,733,238 have disclosed with tertiary amine or quaternary amine and have made catalyzer, dry starch keeps humidity 20%, sprays into a small amount of organic alcohol and makes moistening agent, sprays into catalyzer again, add etherifying agents such as propylene oxide, react 5hrs. down, improve temperature at 18-70 ℃, under partial vacuum, feed rare gas element, evaporation impurity, refined product, after with product slurrying, make film again, gel, drying.U.S.Pat.3,705,891 to have disclosed with the water-soluble phosphate be catalyzer, catalyzer and dry starch are mixed, it is predrying to moisture 8-13%, progressively add propylene oxide then,, make hydroxypropylated starch under the pressure 35-75p.s.i.g. (0.25-0.54Mpa) at temperature 140-190 °F (60-88 ℃).U.S.Pat.4,112,222 have disclosed with water-soluble carboxylate and have made catalyzer, dry starch with catalyst soakage after, predrying to moisture content 6-20%, put into pressurized vessel, add propylene oxide again, at temperature 70-100 ℃, pressure 10-100p.s.i.g. (0.07-0.7MPa.) is reaction 4.5-24hrs. down, after adjusting pH value, washing, drying is made product.
Above preparation technology is all less than the constructional feature that discloses the used key equipment-reactor of dry technology for production in detail.Facts have proved, though general dry process can make corresponding hydroxypropylated starch in the laboratory, but the effective mixing that on industrial production, is difficult to guarantee reactive material with contact, thereby be difficult to guarantee to make the product of quality homogeneous, be difficult to reduce the generation of side reaction.
Summary of the invention
Technical problem to be solved by this invention is: at the disadvantages of background technology part, and provide a kind of industrialized production method that can adjust the synthetic hydroxyalkyl starch of dry method of hydroxyalkyl starch substitution value MS in a big way that is easy to efficiently.
The technical solution adopted in the present invention: starch and alkyl epoxy compound do not have or a small amount of organic dispersing agent in the presence of, under catalyst action, in the patent No. is the disclosed kneading reactor of utility model patent of ZL 00 2 24650.3, reach certain temperature and pressure direct reaction and generate hydroxyalkyl starch, after reaction finishes, neutralize with acid, under normal pressure or partial vacuum, steam dispersion agent, pulverize, the screening back product.
Hydroxyalkyl starch is meant hydroxypropylated starch or hydroxyethylamyle, corresponding raw materials used be respectively propylene oxide or oxyethane, as required, epoxy compounds also can be the mixture of propylene oxide and oxyethane, and the ratio of propylene oxide/oxyethane can be 99/1-1/99 (W/W).Used starch is W-Gum, potato starch, wheat starch, Starch rice, sweet potato starch, tapioca (flour).
The production method of the synthetic hydroxyalkyl starch of dry method of the present invention is to finish in the patent No. is the disclosed kneading reactor of utility model patent of ZL 00 2 24650.3.The constructional feature of this reactor is: the body inner chamber is two gardens column, and two gardens are tangent, in heart position, post garden, garden a Z type stir shaft are set respectively, the diaxon reverse rotation, and certain velocity contrast is arranged, body is outward the chuck layer, can heat or cool off.Material is stainless steel or carbon steel or the carbon steel that dope layer is arranged.This equipment can guarantee solid-solid phase or solid-liquid phase material blended homogeneity, makes material be subjected to effectively powerful kneading effect, successfully carries out efficiently thereby can guarantee to react, and finally guarantees higher product quality and lower production cost.According to the production characteristics of hydroxyalkyl starch, this reactor body inner chamber also can be that the cross section is trapezoid cubes (bottom is still the garden column).In the present invention, this equipment claims to mediate reactor or kneading machine.
The hydroxyalkyl starch dry technology for production also can adopt rake type drier type equipment to implement.Being characterized as of this equipment: body is the garden column, and a stir shaft is equipped with in the central position, and the rake teeth that several become certain orientation is housed on the axle, and axle can positive and negative two directions rotation.Body is equipped with heating or cooling, and to use chuck, material be stainless steel or carbon steel, and the rake teeth material is engineering plastics or copper.
The hydroxyalkyl starch dry technology for production also can adopt following equipment to implement, being characterized as of this equipment: body is the garden column, and an above-mentioned Z type stir shaft is equipped with in the central position, and this axle can the both forward and reverse directions rotation.Body is equipped with heating or cooling, and to use chuck, material be stainless steel or carbon steel.
Beneficial effect of the present invention: the production method of the synthetic hydroxyalkyl starch of the dry method that the present invention discloses makes scale operation have different degree of substitution MS, and best in quality, hydroxyalkyl starch with low cost becomes possibility.
Embodiment
Below be that example is described further with the hydroxypropylated starch:
A certain amount of ative starch (general humidity is 10-18%) is added in the kneading reactor, add the organic dispersing agent of amount of starch 0-100%, organic dispersing agent can be used aliphatic alcohols, as methyl alcohol, ethanol, Virahol, butanols, isopropylcarbinol, primary isoamyl alcohol etc., ketone, as acetone, the benzene class is as benzene, toluene, dimethylbenzene etc., alkanes, as hexanaphthene, hexane, heptane etc.Wherein preferred alcohol or Virahol.The preferred dispersants dosage is the 40-70% (W/W) of starch weight, starts stirring, and material is kneaded into paste.Then add catalyzer, catalyzer can be bases, as sodium hydroxide, and potassium hydroxide, yellow soda ash, calcium hydroxide etc., or be metal carboxylate, phosphoric acid salt, tertiary amines or quaternary ammonium salts, wherein preferred sodium hydroxide or potassium hydroxide.The catalyzer dosage is the 0.1-20% (W/W) of starch weight, and the preferred catalyst dosage is the 0.5-4% (W/W) of starch weight.Catalyst system therefor should wear into-and 2mm fine powder or directly add with flap mediates in the reactor, or sprays into the kneading reactor with less water dissolving back with Sprayable.Material is fully stirred, mediate.Feed rare gas element, as nitrogen, air in the metathesis reactor.At room temperature the propylene oxide with aequum adds.According to the different purposes of hydroxypropylated starch, it should have different substitution value MS, so propylene oxide also is different with the ratio of starch, according to the present invention, this ratio can be regulated arbitrarily, thereby can prepare the product of different degree of substitution MS, is applied to different industrial circles.The propylene oxide dosage is generally the 2-100% (W/W) of starch weight, and preferred dosage is the 3-40% (W/W) of starch weight.After adding propylene oxide, airtight kneading reactor, after fully stirring kneading, through the chuck heat temperature raising, temperature of reaction is generally 40-110 ℃, preferred 70-90 ℃.Reaction pressure is 0.03-1.0Mpa, preferred 0.08-0.5Mpa.This moment, reactor pressure progressively rose to 0.1-0.5MPa.Under said temperature, keep reaction times 1-8hrs., preferred 2-4hrs., along with reaction is progressively carried out, reactor pressure progressively descends after being raised to the peak, after reaction finishes, with the acid neutralization.At temperature 80-90 ℃, steam dispersion agent under vacuum-0.03--0.08MPa subsequently, dispersion agent reclaims through distillation and uses.Material is cooled to room temperature, discharging.According to different purposes, this product can directly be used after the screening through pulverizing.After also this product can being used the aqueous ethanol solution washing, through dehydration, drying is pulverized, the application of screening back.
According to different purposes, hydroxypropylated starch also can carry out cross-linking modified simultaneously.Linking agent commonly used has epoxy chloropropane, Trisodium trimetaphosphate, phosphorus oxychloride etc.Crosslinked method has two kinds, and the one, earlier crosslinked back hydroxyalkylation, promptly linking agent adds before adding the alkyl epoxy compound, and it is crosslinked to heat up, and the back adds the alkyl epoxy compound and implements hydroxyalkylation again; The 2nd, crosslinked and hydroxyalkylation carries out simultaneously, promptly then adds the alkyl epoxy compound after adding linking agent, executes cross-linking of starch and hydroxyalkylation under given condition simultaneously.By the present invention, these two kinds of methods can both be implemented well.The linking agent dosage is generally the 2-2000PPM (W/W) of starch weight.
The production method of the synthetic hydroxypropylated starch of above-mentioned dry method makes scale operation have different degree of substitution MS, and best in quality, hydroxypropylated starch with low cost becomes possibility.
Embodiment given below can further specify the present invention:
Embodiment A
It is in the kneading reactor of 2L that W-Gum 500g. with moisture about 14% adds volume, add 95% (V/V) ethanol 300g, start Z type agitator, add levigated sodium hydroxide 10g, after fully stirring kneading, at room temperature add propylene oxide 156g, airtight kneading reactor, be warming up to 80-90 ℃, under this temperature, keep reaction times 5hrs.With the material cool to room temperature, add acetate and be neutralized to PH6-7, open vacuum pump, be warming up to 80-90 ℃, under vacuum-0.05--0.08MPa, dispersion agent ethanol is steamed, the ethanol that steams reclaims after distillation reaches 95% (V/V) in addition and uses.With material cooling back discharging.Thick product washs three times with 70-80% (V/V) ethanolic soln 1500g, and product is inserted in the former kneading reactor after pressing dry,, at temperature 80-90 ℃, dry 2-3hrs under vacuum-0.05--0.08MPa.Sieve with 20 mesh standard sieves after the product discharging.
Product substitution value MS=0.5
Embodiment B
By embodiment A, but before adding propylene oxide, add epoxy chloropropane 0.4g earlier, the propylene oxide dosage changes 94g into, and all the other conditions are identical with embodiment A with step.This product is cross-linking modified hydroxypropylated starch.
Product substitution value MS=0.3
Embodiment C
It is in the kneading reactor of 1500L that W-Gum 400kg. with moisture about 14% adds volume, add dispersion agent 95% (V/V) ethanol 240kg, start Z type agitator, add flaky sodium hydrate 12kg,, after fully stirring kneading, at room temperature add propylene oxide 175kg, slowly heat up, control pressure is no more than 0.5MPa, reacts 3hrs down at temperature 80-90 ℃.The same embodiment A of post-processing step.
Product substitution value MS=0.7
Embodiment D
By embodiment A, but starch changes moisture about 18% potato starch into, and the propylene oxide dosage changes 32g into.All the other conditions are identical with embodiment A with step.
Product substitution value MS=0.1
Embodiment E
By embodiment A, but starch changes moisture about 18% potato starch into, before adding propylene oxide, adds Trisodium trimetaphosphate 0.01g earlier, and all the other conditions are identical with embodiment A with step.
This product is cross-linking modified hydroxypropylated starch.
Claims (9)
1, the dry method production process of hydroxyalkyl starch, it is characterized in that starch and alkyl epoxy compound do not have or a small amount of organic dispersing agent in the presence of, under catalyst action, in the patent No. is the disclosed kneading reactor of utility model patent of ZL 00 2 24650.3, reach certain temperature and pressure direct reaction and generate hydroxyalkyl starch, after reaction finishes,, under normal pressure or partial vacuum, steam dispersion agent with the acid neutralization, pulverize, the screening back product.
2, the dry method production process of hydroxyalkyl starch according to claim 1, it is characterized in that hydroxyalkyl starch is meant hydroxypropylated starch or hydroxyethylamyle, corresponding raw materials used be respectively propylene oxide or oxyethane, as required, epoxy compounds also can be the mixture of propylene oxide and oxyethane, and the ratio of propylene oxide/oxyethane can be 99/1-1/99 (W/W).
3, the dry method production process of hydroxyalkyl starch according to claim 1 is characterized in that used starch is W-Gum, potato starch, wheat starch, Starch rice, sweet potato starch, tapioca (flour).
4, the dry method production process of hydroxyalkyl starch according to claim 1 is characterized in that organic dispersing agent is an alcohols, as methyl alcohol, and ethanol, Virahol, butanols, isopropylcarbinol, amylalcohol, primary isoamyl alcohol; Ketone, as acetone, methylethylketone; The benzene class, as benzene, toluene, dimethylbenzene, alkanes, as hexanaphthene, hexane, heptane, the consumption of organic dispersing agent are the 0-100% of starch weight.
5, the dry method production process of hydroxyalkyl starch according to claim 1 is characterized in that catalyzer is a bases, as sodium hydroxide, and potassium hydroxide, calcium hydroxide, ammonium hydroxide; Or metal carboxylate, phosphoric acid salt, tertiary amines or quaternary ammonium salts, catalyst levels are the 0.1-20% (W/W) of starch weight, catalyst system therefor wears into-and 2mm fine powder or directly add with flap mediates in the reactor, or sprays into the kneading reactor with less water dissolving back with Sprayable.
6, the dry method production process of hydroxyalkyl starch according to claim 1 is characterized in that temperature of reaction is 40-110 ℃, and reaction pressure is 0.03-1.0MPa.
7, the dry method production process of hydroxyalkyl starch according to claim 1 is characterized in that selecting different degree of substitution MS according to the different purposes of product, and correspondingly the dosage of alkyl epoxy compound is the 2-100% (W/W) of starch weight.
8, the dry method production process of hydroxyalkyl starch according to claim 1 is characterized in that carrying out other starch conversion simultaneously in described technological process, as cross-linking modified.
9, the dry method production process of hydroxyalkyl starch according to claim 8, the linking agent that it is characterized in that the cross-linking modified usefulness of starch are epoxy chloropropane, Trisodium trimetaphosphate, phosphorus oxychloride, mixed acid anhydride and aldehydes; The dosage of linking agent is the 2-2000PPM (W/W) of starch weight; Can the be first crosslinked back of starch hydroxyalkylation, or crosslinked and hydroxyalkylation carries out simultaneously.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031183980A CN1548460A (en) | 2003-05-22 | 2003-05-22 | Dry hydroxyalkyl starch producing process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031183980A CN1548460A (en) | 2003-05-22 | 2003-05-22 | Dry hydroxyalkyl starch producing process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1548460A true CN1548460A (en) | 2004-11-24 |
Family
ID=34320802
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA031183980A Pending CN1548460A (en) | 2003-05-22 | 2003-05-22 | Dry hydroxyalkyl starch producing process |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1548460A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101402690B (en) * | 2008-09-27 | 2011-10-19 | 杭州民生药业有限公司 | Method for preparation of hydroxyethyl starch |
| CN102746408A (en) * | 2012-06-18 | 2012-10-24 | 新疆光大山河化工科技有限公司 | Method for preparing hydroxypropyl starch ether |
| US20130225803A1 (en) * | 2010-12-29 | 2013-08-29 | Samyang Genex Corporation | Method for preparing hydroxyalkyl starch |
| CN103509127A (en) * | 2012-06-30 | 2014-01-15 | 山东光大科技发展有限公司 | Slurry method production process of low-bath-ratio high-substituted hydroxypropyl starch ether |
| CN105481990A (en) * | 2016-01-06 | 2016-04-13 | 中州大学 | Method for preparing hydroxypropyl starch through green high-pressure method |
| CN111763302A (en) * | 2020-07-08 | 2020-10-13 | 清远新力化机有限公司 | TPU (thermoplastic polyurethane) formula for thin film and preparation method thereof |
-
2003
- 2003-05-22 CN CNA031183980A patent/CN1548460A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101402690B (en) * | 2008-09-27 | 2011-10-19 | 杭州民生药业有限公司 | Method for preparation of hydroxyethyl starch |
| US20130225803A1 (en) * | 2010-12-29 | 2013-08-29 | Samyang Genex Corporation | Method for preparing hydroxyalkyl starch |
| CN102746408A (en) * | 2012-06-18 | 2012-10-24 | 新疆光大山河化工科技有限公司 | Method for preparing hydroxypropyl starch ether |
| CN103509127A (en) * | 2012-06-30 | 2014-01-15 | 山东光大科技发展有限公司 | Slurry method production process of low-bath-ratio high-substituted hydroxypropyl starch ether |
| CN105481990A (en) * | 2016-01-06 | 2016-04-13 | 中州大学 | Method for preparing hydroxypropyl starch through green high-pressure method |
| CN111763302A (en) * | 2020-07-08 | 2020-10-13 | 清远新力化机有限公司 | TPU (thermoplastic polyurethane) formula for thin film and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102060618B (en) | Preparation method of water dispersible granule medicinal fertilizer | |
| CN102952199B (en) | Composite modified pregelatinized starch and preparation method thereof | |
| CN111204790B (en) | Method for preparing submicron spherical calcium carbonate based on reverse microemulsion | |
| CN101844884A (en) | Hydrophobic phosphogypsum, and preparation method and application thereof | |
| CN1939932A (en) | Synthesis of soluble amphoteric starch | |
| CN100427398C (en) | Method for preparing nanometer calcium carbonate | |
| CN107568246A (en) | A kind of Graphene antibiosis composite of loading nano silvery and preparation method thereof | |
| CN101318685A (en) | Method for preparing ultra-fine active nano-calcium carbonate with low-ore grade limestone activation of activation tank | |
| CN1548460A (en) | Dry hydroxyalkyl starch producing process | |
| CN1177944C (en) | Method of producing tungstic acid by closed type hydrochloric acid decompose tunstite | |
| CN110183773A (en) | The preparation method of chitosan quaternary ammonium salt organic intercalation montmorillonite composite material | |
| CN107737942B (en) | Zero-valent iron/flower-like zinc oxide nano composite material and preparation method thereof | |
| CN101215385B (en) | Process for preparing nano-starch powder | |
| CN105646941A (en) | Surface modification method of anhydrous calcium sulfate crystal whiskers | |
| CN111440326A (en) | Nanoscale MI L-47 (V) metal organic framework compound and preparation method thereof | |
| CN108190935B (en) | Preparation method of strip-shaped and sheet-shaped calcium carbonate ultrafine particles | |
| CN110420662A (en) | It is a kind of can efficient degradation stalk cellulose at low temperature composite catalyzing material and the preparation method and application thereof | |
| CN102553571B (en) | Preparation method of expandable graphite based composite material | |
| CN1830788A (en) | Technology of transforming common magnesium hydrexide into hexagonal sheel shaped magnesium hydroxide by hydrothermal method | |
| CN113277552A (en) | Titanium-based metal hydroxide and preparation method thereof | |
| CN114681937A (en) | Method for preparing dry suspending agent by combining spray drying and boiling granulation | |
| CN102373507A (en) | Method for hydrothermally synthesizing Bi2WO6 material under assistance of imidazole ionic liquids | |
| CN114983990B (en) | Stable glacial acetic acid-sodium acetate compound and application thereof | |
| CN1587063A (en) | Process for preparing nano alkaline bismuth nitrate by micro emulsion | |
| CN104418677A (en) | Gas generation agent and preparation method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |