Chitosan was chemically modified in different ways to probe their properties when used in soaping agents for reactive dyeing.The experiments showed thatderivations(N, O-CMCTS & NAOC)could remove effectively the loose color in the reactive dyeing to increase the soaping effect in reactive dyeing.Both of N,O-CMCTS and NAOC had good water-solubility and resistance to hardness of water.The first work of this paper is measuring physical properties of .Degree of deacetylation(DD)of determined by acid base titration is about 83%.The MW of chitosan by viscometry is about 1.0×10~5.The effect between chitosan derivatives and hydrolyzed was also studied.The result showed that the stability of micelles composed by NAOC and hydrolyzed was sensitive to its concentration.The soaping effect of both derivatives could hardly be affected by increasing their concentration due to the balance between chitosan derivatives and hydrolyzed reactive dyes.At the same time the conditions affect on the soaping effect of N,O-CMCTS and NAOC,such as the existence of inorganic salt and alkaline, complexation with anionic/nonionic surfactants,have been discussed in detail.The result shows that NAOC had stronger salt-resistance than N,O-CMCTS;the complexation of N, O-CMCTS/NAOC and nonionic surfactant had slightly better soaping effect than that when used separately;while the soaping effect of NAOC was remarkably removed by complexation with anionic surfactant.At last,the concentration of chitosan derivatives,the soaping temperature,time,and pH,et al.were studied when used in soaping agents for reactive dyeing respectively.On the base of experience of above experiment,the reaction conditions of chitosan derivations were systematically investigated through orthogonal design,and then the best conditions were found.N, O-CMCTS:0.50 g/L,90℃,20min,pH=10;NAOC:0.250 g/L,90℃,20min, pH=9.Compared with one of market soaping agents,N,O-CMCTS and NAOC could raise the friction degree and soaping degree by about 0.5 degree.
Post about "chitosan"
With the exaltation of the life level,the consumers like the high quality,nutrient and fresh food more and more.The growth of the microorganism not only is the important reason that makes product putrefied to change its character,and some microorganism possibly do harm to the human body.The antibacterial packing can kill or inhibit microorganism on food surface in the processing, storage,transportation and the treating processes,and also lengthen shelf life and security.In this text,and TiO2 were composited to make a new kind of antibacterial films which were green and edible.Then,choosed the most appropriate process parameters of making films; comparative analyzed the differences between film and /TiO2 antibacterial preservative film in sensory and properties,permeance properties of water vapor and atmosphere,and in antibacterial properties.At last,the film was used to pack strawberry,and its preservative effects was studied.PartⅠ:Making and properties of chitosan film.Different chitosan film was made by different solution concentration of chitosan （0.5%,1%,1.5%,2%,2.5%）and by adding different amount of propanetriol（0%,0.4%,0.8%）,and under different drying condition（dry under ambient temperature for 96h,under 20℃in loft drier for 48h,under 40℃in loft drier for 24h,under 60℃in loft drier for 12h,under 80℃in loft drier for 6h）.Choosed the most appropriate process parameters of making the films through comparative analyzing the differences between chitosan film and chitosan/TiO2 antibacterial preservative film in sensory properties, properties and permeance properties of water vapor and atmosphere. The result showed that the most appropriate process parameters were:solution concentration of chitosan:2%;adding amount of propanetriol:0.4%and dry condition was under 40℃in loft drier for 24h.PartⅡ:Making and properties of chitosan/nanometer TiO2 antibacterial preservative film.Making chitosan/nanometer TiO2 antibacterial preservative film according to the most appropriate process parameters in PartⅠby adding different amount of TiO2（0%,1%,2%,3%,4%）. Through electron microscope we found that nanometer TiO2 had good compatibility with chitosan solution.NanometerTiO2 relatively uniformly distributed in the film although with few micro-aggregate which exist in the level of nanometer size.The research showed that:1)The film became more and more opacity with adding more nanometer TiO2.2)Except adulteration rate of 3%, after adding nanometerTiO2 all the film’s water resistance（R）,tensile strength in wet（σt（wet））and in dry（σt（dry））were increased,thereinto,l%increased most.3)With increasing the amount of nanometerTiO2,film’s activity to Escherichia coli and Staphylococcus aureus had a tendency of increase first then decrease,arid adulteration rate of 3%had the strongest.In summery, 1%is the best adulteration rate.PartⅢ:Differences between chitosan film and chitosan/TiO2 antibacterial preservative film in sensory and properties,permeance properties of water vapor and atmosphere,and in antibacterial property.The result showed that:1)Compared with chitosan film,chitosan/TiO2 antibacterial preservative film’sσt（wet）increased 25.63%and R increased19.15%,which compensated the limitation of chitosan film inσt（wet）,2)Chitosan film and chitosan/TiO2 antibacterial preservative film had similar atmosphere properties and their rate of atmosphere property of CO2 and O2 were close to 4,which is very important to the freshness of fruits.3)Chitosan film’s activity is strong and fast but chitosan/TiO2 film’s is stronger,faster and can last for a long time.After touched with bacterial liquor for 24h,the respective antimicrobial activity to Escherichia coli and Staphylococcus aureus were 98.3%and 95.5%,after 48h were 96.9%and 94.2%,besides,under glimmer chitosan/TiO2 film still had good antimicrobial activity.PartⅣ:Compared the preservation effect of chitosan film and chitosan/TiO2 antibacterial preservative film.The result showed that:Their effect were close and chitosan/TiO2 antibacterial preservative film’s was a little better.Used chitosan film and chitosan/TiO2 antibacterial preservative film to pack strawberry can keep strawberry fresh for 5 days under ambient temperature and 12 days in cold storage with only little blet.
In this article,Hydrogen production from ethanol steam reforming over Ni/Al2O3 catalyst which was prepared by chelated with chitsan and Impregnation was investgated.Reaction effect with different ways of preparation and reaction condition were researched.And basicoxide were joined in by impregnation and mixed,then whose reaction effect was reseached.At last,specific surface,X radial diffraction,and the thermogravimetric analysis on Ni/Al2O3 was performed.The condition of preparation had a marked influence on catalyst ‘s effection.Carrier was aired at ambient’temperature which the proportion of aluminium nitrate andwas 3.Then was calcined at 600℃for 2 hours.Ni whose weight rate was 10%was loaded by impregnation with nickel nitrate.The impregnated catalyst was placed in air for 24h,and dried at 120℃ for 8h,then calcined at 550℃for 1h.In the fixed-bed reactor,the catalyst was reduced at 650℃for 1h.In this circs,the activity and selectivity of catalyst was ideal.When the reaction temperature was 500℃,the molar ratio of water and ethanol was 4,and space velocity was 9.6h-1,selectivity of H2 was 66.6%, ethanol translated completely,selectivity of CO and CH4 were 4.2%and 12.9%,and selectivity of CO2 was 16.3%.Basicoxide was joined as sorbent in by mixed（weight ratio of and are 10%and 90%）and impregnation（weight ratio of and are 5%and 10%）.But the reaction result was not good as expected.And was not suit as sorbent apparently.The result of token showed that oxidation state of 10Ni/Al2O3,oxide nickel dispersed among the surface of carrier.after was reduced, monoplasmatic nickel crystal showed up.When reacting,Hydrogen produced from ethanol steam reforming by the combined action of oxide nickel and monoplasmatic nickel.And there was a proper proportion between them.After nickel was loaded,surface area,Diameter and volume of bore diminished. May be had agglomerated after it was calcined.
The molecule ofcontains high contents of amino groups, which can be protonated by integrating H+ in solution. So has favorable adsorbability to some inorganic acid, organic acid, acor compound. Chitosan can be dissolved in acid solution. limits its application as absorbent.The references about the structure characteristics, properties and modification research actualities and its practical application had been investigated sufficiently. On the basis of this, using glutaradehyde as the cross-linker, magnetic chitosan microspheres (MCTS) were prepared by the suspension cross-linking technique.The experiments had been carried out to study the behavior of MCTS for three kinds of phytohormone. In the medium of isopropanol, using perchloric acid as catalyst, hydroxypropyl chloride magnetic chitosan microspheres (ECH-MCTS) were prepared. Furthermore, aminated magnetic chitosan microspheres (EN-MCTS) were prepared by grafting ethylenediamine on the microsphere surface. The efficiency of aminated magnetic chitosan microspheres were investigated in removal of anoinic dyes acid rhodamine B(AR)、fuchsin acid (FA) and reactive brilliant blue X-BR (RBB) compared with MCTS and ECH-MCTS. The adsorption thermodynamics, kinetics and mechanism were discussed. Chitosan powder had been prepared to be magnetic resin. To the contribution of magnetic field, the chitosan and the resin can be easily isolated. This expanded the application of chitosan consumedly. The major study works and results were as follows:1. The preparation and characterization of magnetic chitosan microspheres.The effects of the dosage of crosslinker glutaraldehyde on microspheres morphology and yield had been observed intensively. The modality observed by optical microscope show that, the yield of microsphere increased, but the aggregation of the microspheres became more serious as the quantity of crosslinker increasing and the adsorption values to abscisic acid decreased correspondingly. The reason was that the amino groups on the surface of the microspheres had been occupied by overmany crosslinker. Therefore, when the crosslinker concentration was 7% and the qantity of the chitosan was 0.5 g, the with good dispersion property and uniformity the particle size diffusion were obtained.Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to investigate the morphology and size of the microspheres. The results indicated that the microspheres had well shaped spherical form with smooth surface and the particle size was 3~5μm. The fourier transfor IR (FT-IR) spectrameter , X-ray diffraction (XRD) , differential scanning calorimetry (DSC) and thermogravinetry (TG) were used to analyze the molecular structure and the alteration of the microspheres’thermal character. The results showed that Fe3O4 nanoparticles remained its spinel structure, which packed in the microspheres to form core-shell structure, and the weight percentage of Fe3O4 nanoparticles was estimated to be about 10.9 wt%. The thermal stability of MCTS was lower than chitosan, but was as high as chitosan before 225℃, and also can be easily separated from aqueous solution under the magnetic field.2. The studies of adsorption behaviour and mechanism for acidic phytohormone onto magnetic chitosan mocrospheresMCTS was utilized to adsorb abscisic acid (ABA), gibberellin (GA3) ,3-indoleacetic acid (IAA) by static adsorption. The effects of adsorbent dosage, contact time, pH and the original concentration of ABA, GA3, IAA on the adsorption rate were investigated and optimized. In order to explore the adsorption mechanism of the modified microspheres, the experimental data were fitting by dynamics model including pseudo-second-order equation and pseudo-first-order equation, and isotherms Langmuir and Freundlich isotherms. The results showed that the adsorbent dosage was appropriated at 1.25 g L-1. In 20 minutes ,the adsorption rate to ABA(c0 = 32.28mg L-1),IAA(c0 = 43.80mg L-1),GA3(c0 = 200.0mg L-1)raised up to maximum, and the one step adsorption rate was 89%,93% and 81% respectively. Furthermore, the adsorption efficiencies were greatly influenced by the acidity and ionic strength of solution. A possible explanation for pH effect on adsorption may be related to the surface charge of and phytohormone. Amino groups on the surface of microspheres played a major role in adsorption proces. It could be protoned in low pH, combining with acid radical ion dissociated by ABA, IAA or GA3 to complete the adsorption process. So when the pH is too low, amino group couldn’t be protonated easily, but the high acidity impeded the dissociation of ABA, IAA and GA3. And aslo as the increase of ionic strength, high concentrations of NaCl ions could cover the particle surface and form an ion shield, which can decrease the diffusivity of phytohormone and enlarge the absorbed molecules, and therefore reduce the adsorption rate.The results for the experimental data applying pseudo-first-order equation and pseudo-second-order equation showed that the adsorption for phytohormone conformed to the pseudo-second-order equation. It confirmed that the adsorption rate was controlled by chemical sorption. The isotherms model of ABA and GA3 of the modified microspheres indicated that Langmuir isotherm equation gave better fit than the Freundlich isotherm. It confirmed that the adsorption on microspheres was in a monolayer form. The regeneration of the adsorbents could be implemented by 0.1 mol L-1 sodium chloride , only the 5% decrease of adsorption rate could be obtained after regenerating absorbents for five times. These results indicated that the magnetic chitosan microspheres can be recycled.3. The preparation and characterization of modified magnetic chitosan microspheres.The adsorption efficiency of chitosan closely related to its alkalinity. Cross-linking reaction weakened the alkalinity of absorbent and reduced the adsorption efficiency of absorbent. Thus, two kinds of modified microspheres were prepared in order to increase the adsorption efficiency.①Preparation of hydroxypropyl chloride magnetic chitosan microspheres (ECH-MCTS) by using epichlorohydrin modified magnetic chitosan microspheres②Preparation of a new adsobent aminated magnetic chitosan microspheres (EN-MCTS) by using ethylenediamine grafted on the surface of microspheres.The content of amino groups on microspheres were determined by titrimetric method. IR , XRD ,DSC and TG were used to analyze the alteration of ECH-MCTS and EN-MCTS’molecular structure and characte. The results showed that the amino group content of ECH-MCTS decreased obviously. It indicated that both amino groups and hydroxy groups participated in the reaction with ethylenediamine. However, the amino group content of EN-MCTS was twice than that of MCTS. So the alkalinity of EN-MCTS had been strengthened and the adsorbability had been enhanced .4. The studies on adsorption behaviour and mechanism for anionic dye onto MCTS, ECH-MCTS and EN-MCTSThe adsorption behaviour for the three anionic dyes acid rhodamine B, fuchsin acid and reactive brilliant blue X-BR were studied, the experimental factors contact time, pH and temperature had also been explored and optimized. The results showed that within 60 minutes, the adsorption rate for AR and FA on EN-MCTS can reach to 95%, when the original concentrations of AR were chosen at 0.50 mmol L-1, FA were at 0.80 mmol L-1, and the adsorbent dosage was at 0.5 g L-1 and 0.8 g L-1 respectively. However, within 4 hours, the adsorption rate for RBB can reach to 98% on EN-MCTS when the original concentrations were chosen at 0.30 mmol L-1 and the adsorbent dosage was at 0.8 g L-1. The adsorption capability could be enhanced as the concentration of dyes increasing, while the adsorption rate decreased as the acidity increasing on the three . But the adsorption on MCTS was affected greatly by the solution acidity compared with ECH-MCTS and EN-MCTS. The results indicated that the adsorption for anionic dyes were affected by the structure of dyes and the steric hindrance of amino groups on microspheres .The results for the experimental data applying dynamics equations and isotherm equations showed that the adsorption for anionic dyes conformed to the pseudo-second-order equation and Langmuir isotherm equation. It confirmed that the adsorption process was in monolayer controlled by chemical sorption. The regeneration of the adsorbents could be implemented by 0.5 mol L-1 NaOH + 2 mol L-1NaCl (V/V=1:1) , the second-regenerated ratios were all > 95%.
A novelof supported by active carbon was prepared using the emulsification cross-linking technique, which include first pre-crosslinking, second quasi-crosslinking and final releasing of amino sites. was applied in the of low concentration NO2--N in drinking water. The effect of preparation conditions on granulation rate and capacity was studied so did the pretreatment of activated carbon. In order to reduce the preparation cost, recycling use of liquid paraffin was researched. In the adsorptive experiment, the effect of partical size, pH, adsorption kinetics, adsorption thermodynamics, adsorption selectivity, adsporption mechanism and saturated adsorption capacity were studied. is found that the granulation rate is affected greatly by the partical size of activated carbon, emulsifier span 80, dispersant liquid paraffin, formaldehyde and concentration while the adsorption capacity is affected by crosslinking agent and ethyl acetate. The preparation conditions are that the partical size of activated carbon is less than 0.15mm, the concentration of is 3%, the mass ratio of activated carbon to chitosan is 0.5, emulsification is at room temperature, the volume ratio of span80 to liquid paraffin, liquid paraffin to acetate solution and ethyl acetate to acetate solution are 3‰,1.5 and 0.03 respectively.The functional groups ratio of formaldehyde and epichlorohydrin to chitosan are 38.4 and 2.8 respectively.The SEM image indicates that the surface of the resin was uneven and had many developed micropores. The infrared spectrum shows that every reaction step has happened.Adsorption capacity of increases when activated carbon was treated by HC1, while the characteristic parameters of are lower than those of the chitosan resin for the addition of activated carbon. Because of the recycling use of liquid paraffin, the productive cost and wast discharge reduce while the characterisitic change slightly. With the partical size increasing, the mass distribution improves, while adsorption capacity drops slightly. The adsorption capacity of chitosan composite resin is much greater than the simple compounding made up of activated carbon and chitosan resin. When the temperature is lower than 40℃, the adsorption is a physisorption process primarily caused by electrostatic attraction, so it can be regenerated by HC1. The adsorption selectivity of composite resin for NO2--N is affected by the concentration and negative charge number of co-existing anions. The adsorption reached equilibrium in 60 min with a calculated equilibrium capacity of 0.479 mg/g. When the temperature is higher than 40℃,the adsorption is a chemisorption process caused by chemical bond force and adsorption selectivity for NO2--N increases. The adsorption reached equilibrium in 90min with a calculated equilibrium capacity of 0.700 mg/g. Adsorption capacity increases but the velocity decreases. The saturated adsorption capacity is greater than 2.563 mg/g .Chemisorption is endothermic, spontaneous, entropy increasing process and it can not be regenerated by HC1. The chemisorption and physisorption isotherm equations are conformed to the Freundlich model, and the adsorption process accords with second-order kinetic rate mode.
In this paper, the modification ofand apply them in have been researched. Concentrate on sponge carrier, cross-linking carrier and KGM-ALG microballoon sphere. Besides these, properties of the free urease and immobilized urease were also discussed. The characterizations by light microscope, SEM and FT-IR provide academic supports.The conduct of low temperature treatment before infusibility treatment made the carrier show an appearance of sponge and springiness. Its’ properties such as merchanic intensity, storage stability and using ability are all improved. And boasts a high sensitivity in the change of pH and has a better compatibility on substract.The cross-linking immobilized urease enjoys great storage stability, after stored in 4℃for about 30 days, its’ enzyme activity appears litter lose. When we install 10.0g immobilized urease of this kind into a pillar and use to catalyse urea-phosphate buffered solution for 3 days in run, totally catalyse 1000ml urea-phosphate buffered solution, and then sealed with film, stored it in 4℃for around four months, and the enzyme activity remains 40%.KGM-ALG microballoon sphere immobilized urease boasts good enzyme activity over 8.9U/g. We can adjust the enzyme release rate and merchanic intensity through changing the proportion of KGM, ALG sol and the concentration of . The method is easy-conduct, mild-condition, fitting many substances’ immobilization from active protein medicine, enzyme to hydrophobe, and available for massive production.
This dissertation is organized in two parts:Part 1:Studies on the Interaction between Chitosan and The interaction between Chitosan（CS） and （HOBt） wasstudied by 1H spectroscopy,NMR diffusion measurement,and solid statehigh-resolution 13C NMR spectroscopy.CS and HOBt were found to be able to formorganic complex,and the main binding force is .Theassociation constant of CS/HOBt complex was calculated from the self-diffusioncoefficients of HOBt.CS/HOBt system would be efficient in chemical modificationof CS without the use of acids or organic solvents.Part 2:Preparation and NMR Study of /DNA ComplexesWater-soluble Chitosan was prepared by functionalizing with poy（ethyleneglycol） methyl ether（mPEG） at the ammo and hydroxyl groups via a single reaction ina CS/HOBt aqueous system.The product was characterized by NMR,IR etc.The was complexed with DNA at various /DNA（N/P） chargeratios and the resulting complexes was characterized by IR,gel retardation,dynamiclight scattering,solid state NMR 31P DD/MAS spectra and 13C CP/MAS spectra todetermine the complex formation and the interaction between CS-g-mPEG and DNA.The results indicated that:The solubility of CS was improved to 50mg/mlH2Othrough functionizing with mPEG and the 1H spin-diffusion NMR experiments with13C detection showed their good compatibility;the was formed at higher charge ratio（N/P>10）.In the 31P DD/MAS spectra,the chemical shiftof the phosphate group of DNA was found to be dependent on the charge ratio.Thesame phenomenon was got in the 13C CP/MAS spectra.Both of these results indicatethat higher the charge ratio,then better the compatibility of the system.
Preparation of Xanthan Acidification Crosslinked Chitosan and Study on Its Adsorption on Heavy Metal Ions
Chitosan is the natural polymer containing amido and hydroxyl groups, which can coordinate with metal ions well. Its adsorbing capacity can be enhanced by changing chemical characteristic of the molecule, and its treatment of metal ions containing waste water is paid attention in recent year.Firstly, the schiff’s bases between the benzaldehyde and theat the normal temperature was studied in this paper, then was cross-linked with epichlorohydrin and ethylenediamine; protection group drawn off by using hydrochloric acid after cross-linking, finally, was xanthan acidificated by carbon bisulfide, and the final production was gained at the same time. A best reaction condition was gained through orthogonal experiment: materiel ratio is 1:2, reaction temperature is 40℃, and -OH medium’s chroma is 0.2mol/L,reaction time is 4 hours. And many analyzing measures such as FTIR, XRD and element analysis was adopted for characterizing the CTSN-CS2 and its middle production, the results showed that the product was correspond with the results supposed before.The adsorbent activity for Cu2+、Ni2+、Pb2+ of CTSN-CS2 was studied from five aspect namely, capacity、medium acidity、 kinetics、 isotherm and regeneration. Tests showed that the adsorption of CTSN-CS2 on Cu2+、Ni2+、Pb2+ were 2.645mmol/g、1.943mmol/g、1.856mmol/g in initial concentration 3.0mmol/L of solution. The adsorption performance was influenced dramatically by medium acidity. When the pH was low, the absorbent’s adsorption capacity was quite low to three kind of metal ion’s. Along with the pH ‘s elevation, the metal ion’s adsorptive capacity increased. The best pH was 5-6.CTSN-CS2 had the quick dynamics speed to three kind of ion’s adsorptions, was quickest to the Cu2+ adsorption, approximately 4h achieves balanced, and the adsorption rate order is KCu> KNi > KPb. The tests of Adsorption kinetics showed:the uptake of CTSN-CS2 Cu2+、Ni2+、Pb2+increase with the increasing of initial concentrations until reache plateau. The uptake datas were analysed by the Langmuir isotherm and the Freundlich isotherm, and show the adsorption isotherms could be well fitted by the Langmuir equation. In the Cu2+、Ni2+、Pb2+ ternary system, the adsorption capacity for Cu2+、Ni2+、Pb2+ of CTSN-CS2 declined. had the high adsorption capacity and the adsorption selectivity to Cu2+, lower to Ni2+and the Pb2+ adsorption capacity and the adsorption selectivity.
Aryl ethers are important compounds, and there are also important applications in pesticides, pharmaceuticals, fragrances, dyestuffs and so on. Recently, more and more research has been focused on their synthesis. The Pd-catalyzed synthesis ofs has been reported, however, this catalytic process has many disadvantages, such as the multiple intermediate products, lower yield, difficult recovery of catalyst and high cost. Chitosan is the natural polymer containing -NH2 and -OH groups, which can coordinate with metal ions well. Since the -supported noble metal catalysts have high stability, little causticity and low-solvents-solubility, all of which is easy to the separation, recovery and reuse of catalysts. The research and application of the natural polymer -supported palladium catalyst is paid attention in recent years.First of all, the survey of research on s and supported palladium catalysts, and the recent advance in the study on the chitosan-supported palladium catalyst applications were reviewed in this paper. According to the investigation of reference, shows that the palladium complexes used as catalysts to synthesize s had been studied, but the chitosan-supported palladium complex for this catalyzed synthesis has not been reported.Secondly, Natural chitosan-supported palladium, modified chitosan with salicylad- ehyde palladium complex, and SiO2 supported chitosan Schiff-base palladium catalys- ts were prepared by immersion method using chitosan and palladium chloride as raw material. These catalysts were characterized by FT-TR and NMR; the results showed that chitosan had coordinated with palladium well. At the same time, the synthesis method of 4-nitrodiphenyl ether was discussed. is concluded that there is a relative reasonable route for this synthesis of 4-nitrodiphenyl: this reaction use p-nitrochlorob- enzene, phenol and sodium hydride as material, toluene as solvent, chitosan-supprted palladium as catalyst.Thirdly, the performance of chitosan-supported palladium catalyzed synthesis of diphenyl ethers was studied. An orthogonal test was designed; Effects of the molar ratio of materials, reaction temperature, reaction time and catalyst consumption on the yields were investigated. The results indicate that the optimal reaction conditions are: 1:1molar ratio of phenol and p-nitrochlorobenzene, 2:1molar ratio of sodium hydride and p-nitrochlorobenzene, 30mL toluene, 0.20g catalyst, 65℃for 9h under an atmos- phere of nitrogen. Under these conditions, the yield of 4-nitrodiphenyl is 79.0%. Similarly, under the optimal reaction conditions: 1.5:1molar ratio of phenol and p-nitrochlorobenzene, 2:1 molar ratio of sodium hydride and p-nitrochlorobenzene, 30 mL toluene, 0.20g catalyst, 100℃for 10h under an atmosphere of nitrogen, the yield of 4-phenoxyaniline is 78.4%. The catalyst has good activity and good repeatability, for it can be separated easily from the product with extraction, then reuse for many times.Finally, the chitosan-palladium complex catalysts on SiO2 were prepared, and the catalytic performance of this catalyst in the synthesis reaction of alkyl aryl ethers was explored. The research reveals that this catalyst has good catalytic activity in the reac- tion, especially in the synthesis reaction of p-nitroanisole by using p-nitrochlorobenz- ene, methanol and sodium hydroxide as raw material, the reaction condition is also mild.In a word, these catalysts are easily prepared, separated from the reaction mixture, reclaimed and reused, meanwhile, they perform high activity for the synthesis of aryl ether.
The rapid development of modern biotechnology brings about many protein and peptide drugs, which are degradable by proteolytic enzyme in intestinal and not oral. Moreover, most protein and peptide drugs are hard through the biological barrier, resulting in low bioavailability, and only can be used by injection and perfusion. The most drugs release quickly after administrated, which brings the drug level increases rapidly and decreases after reaching the peak. For drugs, the effect is closely related to the concentrations in serum. So the fluctuation of concentration leads to unaccepted side-effect at the peak, and inadequate treating effect at low drug concentrations. Drug delivery system is catering to said problems, and becoming an important developing in drug field recently, so the selecting and researching of drug carriers or delivery materials become a research focus. The delivery materials with extensive sources, poisonless and harmless, and high encapsulation efficiency are pursued by people.In this paper, the delivery material of hydroxypropyl-was prepared by hydrophilic modification of , basing on researches for the condition of forming chitosan particles and the effect of drug delivery. Then by coupling which has the target effect of to hydroxypropyl-chitosan, the -hydroxypropyl-chitosan was prepared and the drug delivery result of -hydroxypropyl-chitosan particles was studied. The major contents and results include:1. The chitosan nanoparticle was prepared by ion gel. The condition of chitosan forming sphere was determined and the nanoparticle was characterized by TEM. The results of encapsulation and delivery were studied by taking bovine serum albumin (BSA) as model drug. The results showed that the BSA encapsulation efficiency and the BSA loading were affected by the initial CS concentration and the initial BSA concentration. The higher was the initial chitosan concentration, the higher the BSA encapsulation efficiency and the BSA loading. However, showed opposite trend when the initial BSA concentration increased. The highest encapsulation efficiency and loading of BSA reached 86% and 49%, respectively. The behavior of chitosan nanoparticles for BSA in vitro release reveals a controlled and continuous release of the entrapped protein after 12 hours and releases 30% of the BSA loading within 2 hours.2. By the reaction of propylene oxide and chitosan under alkaline condition that introducing hydroxypropyl to chitosan, the water-soluble hydroxypropyl-chitosan (HCS) was prepared. The synthesis of hydroxypropyl-chitosan was determined by Fourier Transform Infrared Spectroscope. The hydroxypropyl-chitosan particles were observed by TEM, and the effect of encapsulation and delivery was also researched. The results suggested that the prepared hydroxypropyl-chitosan particle was characterized by regular sphere, uniform distribution of particle size, high encapsulation efficiency, high drug loading and good delivery, and the highest encapsulation efficiency and loading of BSA reached 86% and 46%, respectively. The behavior of HCS nanoparticles releases 28% in average within 2 hours and reveals a continuous release of the entrapped protein.3. The folate-hydroxypropyl-chitosan (FHCS) was prepared by the folate coupled to hydroxypropyl-chitosan under the condition of neutral aqueous solution and dark environment. The effects of temperature, concentrations and time on FHCS yield were studied. The result suggested that the optimal values of content, time and temperature were FHCS 2.0mg/ml, folate 120μg/ml, 70min and 80℃, respectively. The highest yield is 31.3%. Then the folate-hydroxypropyl-chitosan particles was prepared by ion gel, characterized by TEM,and meanwhile, the effect of encapsulation and delivery were researched. The results showed that the prepared folate-hydroxypropyl-chitosan particle had advantages of regular sphere, uniform distribution of particle size. And the highest encapsulation efficiency and loading of BSA reached 90% and 48%, respectively. The FHCS nanoparticles releases 26% in average within 2 hours and reveals a continuous release of the entrapped protein.