CN102942691B - Synthetic method of hemicellulose graft polypropylene oxide - Google Patents
Synthetic method of hemicellulose graft polypropylene oxide Download PDFInfo
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Abstract
The present invention relates to a synthetic method of hemicellulose graft polypropylene oxide. The synthetic method includes the following steps: (1) dissolving: adding the hemicellulose to LiCl and N,N-dimethylacetamide or N, N-dimethylformamide, stirring for 3-5 h in the presence of nitrogen at 80-120 DEG C, and fully dissolving the hemicellulose; (2) reacting: cooling the solution from step (1) to room temperature, adding a catalyst, stirring for 10-30 min, adding propylene oxide, and reacting at 20-60 DEG C for 24-48 h; (3) precipitating and purifying: adding the resulting solution to a water-ethanol mixed solution to precipitate a reaction product, centrifugating or filtering to obtain a precipitate, and dialyzing the obtained precipitate for 1-2 days; and (4) drying. Compared with conventional catalysts such as KOH, double metal cyanide, and rare earth complexes, the catalyst used in the method of the present invention has the advantages of no side reactions, no toxic, low price, easy acquisition, etc.
Description
Technical field
The present invention relates to hemicellulose, particularly a kind of synthetic method of hemicellulose graft polypropylene oxide.
Background technology
The cell walls of higher plant forms primarily of Mierocrystalline cellulose, hemicellulose and xylogen, its quality accounts for 80 ~ 95% of cell walls, be the main chemical compositions forming plant fiber material, wherein the content of hemicellulose is only second to Mierocrystalline cellulose, accounts for 1/4 ~ 1/3 of plant material.Hemicellulose is homogeneous glycan not, but the general name of a group complex plycan, be the polysaccharide polymer be made up of several dissimilar five-carbon sugar and hexose.Due to the difference of raw material sources, the component of complex plycan is also variant, and the structural unit of composition hemicellulose mainly contains: D-wood sugar, D-Glucose, D-MANNOSE, D-semi-lactosi, L-arabinose, L-fucose, D-Glucose aldehydic acid, 4-O-methyl-D-glucose aldehydic acid, D-galacturonic acid and a small amount of L-rhamnosyl and the methylated neutral sugar of various O-etc.Natural hemicellulose has the features such as non-crystalline, lower molecular weight and multi-branched, and the polymerization degree, usually 80 ~ 200, generally can adopt water or basic solution to extract from plant cell wall.According to the difference of hemicellulose backbone monose type, usually hemicellulose can be divided into four classes from structure: (1) polyxylose, with β-(1 → 4)-D-xylosyl for main chain, be connected on O-2 or O-3 of main chain xylosyl with the different oligose of 4-O-methyl-D-glucose aldehydic acid base, L-arabinose base, D-galactosyl and D-xylosyl composition, be present in Gramineae and broad leaved plant cell walls more; (2) poly-semi-lactosi seminose, with β-(1 → 4)-seminose for main chain, and D-semi-lactosi is connected on the C-6 position of main chain seminose, is mainly present in needlebush.(3) polyxylose glucose, with β-(1 → 4)-glucose for main chain, wood sugar is connected on main chain C-6 position, is mainly present in dicotyledonous angiosperm.(4) poly-β-glucose, is formed by connecting with β-(1 → 3) and β-(1 → 4) glycosidic bond, in the aleurone layer being mainly present in cereal cell wall and endosperm.
Along with the minimizing gradually of consumption and the storage capacity day by day of the Nonrenewable resources such as oil, the renewable resourcess such as biomass are utilized to be converted into novel material, industrial chemicals, clean energy, functional food and medicine etc., supplement or progressively substitute fossil base product and become new development trend, be classified as the Major Strategic of economy and social sustainable development in China especially.China's agricultural abandoned biomass aboundresources, therefrom can be separated and obtain a large amount of hemicelluloses, utilize the hydroxyl on hemicellulose structural unit, be converted into through chemical modification (esterification, etherificate, crosslinked and grafting etc.) focus that high-valued product has become current research.Hemicellulose and derivative thereof have purposes widely in fields such as food, medicine and materials due to its good bio-compatibility, degradability and biological activity, such as, based on the food packaging film of hemicellulose, xylo-oligosaccharide, chemical, intelligent aqueous gel capable and sorbent material etc.
The hydroxyl that hemicellulose enriches and shorter molecular chain cause it to have stronger wetting ability and lower thermoplasticity, and this feature limits the wider application of hemicellulose.In the research of numerous hemicellulose chemical modification, graft polymerization reaction by introducing longer side chain (as branch) on hemicellulose backbone, owing to there is the effect such as chemical bond, hydrogen bond and winding between side chain and main chain thus improving the performance of hemicellulose, this reaction because having efficiently, the advantage such as Design and Features now obtains extensive concern.
At present, (1) catalyzer is concentrated on for the research of propylene oxide ring-opening polymerization, such as the catalysis such as KOH of traditional alkali metal hydroxide cause propylene oxide ring-opening polymerization (patent No. is 98122854.2), but cause methyl proton due to high basicity simultaneously thus produce a large amount of side reactions; An aromatic plant metioned in ancient books in Shen and Zhang Yifeng adopt rare-earth complexation catalyst to prepare high molecular weight epoxyalkane (patent No. is 85104956), although the method polymerizing condition variation range is wide, because rare earth not easily obtains, thus limit this catalyzer and use on a large scale; The synthesis polyalkylene oxide that employing double metal cyanide can be controlled rapidly in recent years, but this catalyzer belongs to prussiate, huge to harm.(2) initiator, disclosed patent mainly with low molecular weight monomers as ethylene glycol, glycerine, monose, quadrol and carbonic acid gas etc. (patent No. 01135931.5 and 200710055513.2) are initiator, and the research under KOH catalysis as initiator and propylene oxide using Mierocrystalline cellulose and hemicellulose superpolymer, hydroxypropylcellulose or hydroxypropyl hemicellulose are just prepared, grafting does not form side chain (the Zhou JP et al. of long molecular chain, J.Polym.Sci.Pol.Chem.2004, 42, 5911-5920 and Jain RK etal., Cellulose, 2001, 7, 319-336), and any patent application and report be there is not yet for the synthesis of hemicellulose graft polypropylene oxide.
Summary of the invention
In order to overcome the above-mentioned shortcoming of existing propylene oxide ring opening catalyst and widen the application of hemicellulosic materials, the object of the present invention is to provide a kind of synthetic method of novel hemicellulose graft polypropylene oxide, have simple, cheap, graft(ing) degree is high and react the feature such as efficient.
As shown in Figure 1, the synthesis of the hemicellulose graft polypropylene oxide that the present invention relates to is propylene oxide open loop and hemicellulose hydroxyl generation etherificate under catalyst action, and forming the side chain reaction of polyoxypropylene ether structure, the hemicellulose graft polypropylene oxide obtained can be used for preparation hydrophobic and heat-staple food packaging film and amphipathic sorbent material etc.
Object of the present invention is achieved through the following technical solutions:
A synthetic method for hemicellulose graft polypropylene oxide, comprises the following steps:
(1) dissolve: hemicellulose is joined in LiCl and N,N-dimethylacetamide (DMA) or DMF (DMF), at 80 ~ 120 DEG C of stirred under nitrogen atmosphere 3 ~ 5h, CL hemicellulose; Described hemicellulose and N, N-N,N-DIMETHYLACETAMIDE or N, the mass volume ratio of dinethylformamide is 1: 1000 ~ 1: 20, LiCl and N, N-N,N-DIMETHYLACETAMIDE or N, the mass volume ratio of dinethylformamide is 1: 25 ~ 1: 10, and the unit of described quality is g, and the unit of described volume is ml;
(2) react:
(2-1) step (1) gained solution is down to room temperature, adds catalyzer, stir 10 ~ 30min, in described catalyzer and hemicellulose, dewatering unit mol ratio is 0.1: 1 ~ 2: 1; Described catalyzer is the aluminum isopropylate being dissolved in toluene;
(2-2) add propylene oxide, at 20 ~ 60 DEG C, react 24 ~ 48h; The mol ratio of propylene oxide and hemicellulose dewatering unit is 1: 1 ~ 30: 1;
(3) precipitate: the solution that step (2-2) obtains is joined precipitin reaction product in water-ethanol mixing solutions, be precipitated thing through centrifugal or filtration;
(4) purifying: the throw out that step (3) obtains is carried out dialysis 1 ~ 2 day;
For realizing the object of the invention further, described hemicellulose is any one in polyxylose, poly-4-O-methyl-D-glucose aldehydic acid base aralino wood sugar, poly-semi-lactosi seminose, polyxylose glucose and poly-β-glucose.
In the described water-ethanol mixing solutions of step (3), the volume percent of ethanol is 90 ~ 95%.
Step (4) dialysis tubing molecular weight cut-off is 1000 ~ 5000Da.
Step (5) described drying is lyophilize, and temperature is-40 ~-60 DEG C, and vacuum tightness is 200 ~ 300mba, time 12-48h.
Step (5) described drying is vacuum-drying, and temperature is 30 ~ 50 DEG C, and vacuum tightness is 0.5 ~ 1.5MPa, time 12-48h.
Compared with prior art, the present invention has the following advantages and beneficial effect:
The catalyzer that method of the present invention adopts is compared with rare-earth complex with traditional KOH, double metal cyanide, has without side reaction, the advantage such as nontoxic and cheap and easy to get.The hemicellulose graft polypropylene oxide graft(ing) degree utilizing method of the present invention to synthesize is 50% ~ 70%, has no other hemicellulose graft polypropylene oxide report.
Accompanying drawing explanation
Fig. 1 is polyxylose and propylene oxide graft polymerization reaction formula.
Fig. 2 is polyxylose
13c NMR spectrogram
Fig. 3 is reaction product polyxylose grafting poly(propylene oxide)
13c NMR spectrogram.
Embodiment
For understanding the present invention better, below in conjunction with embodiment and accompanying drawing, invention is described further, but embodiments of the present invention are not limited thereto.
Graft(ing) degree (GD) testing method below in embodiment is as follows: GD=[(W
1-W
0)/W
0] × 100%, wherein W
0and W
1be respectively the weight of hemicellulose before and after reaction, weight unit is g.
Embodiment 1
The synthetic method of a kind of hemicellulose graft polypropylene oxide of the present embodiment, comprises the following steps:
(1) dissolve: in the LiCl that 1g polyxylose is joined 100ml and N,N-dimethylacetamide, LiCl and N,N-dimethylacetamide mass volume ratio are 8%, and the unit of described quality is g, and the unit of described volume is ml; At 100 DEG C of stirred under nitrogen atmosphere 4h, CL hemicellulose;
(2) react:
(2-1) step (1) gained solution is down to room temperature, adds the aluminum isopropylate being dissolved in toluene, stir 10min, wherein in aluminum isopropylate and hemicellulose, dewatering unit mol ratio is 0.25: 1;
(2-2) propylene oxide is added in following ratio: the mol ratio of propylene oxide and hemicellulose dewatering unit is 30: 1, at 60 DEG C, react 24h;
(3) solution that step (2-2) obtains is joined 95%(volume) precipitin reaction product in ethanolic soln, be precipitated thing through centrifugal;
(4) throw out step (3) obtained is dialyse 2 days in the dialysis tubing of 3500Da at molecular weight cut-off;
(5) dry: adopt lyophilize, temperature is-40 DEG C, and vacuum tightness is 200mba, time 24h.
Fig. 2 is polyxylose and reaction product hemicellulose graft polypropylene oxide in the present embodiment
13c NMR spectrogram, as can be seen from Fig. 2 and Fig. 3, with script polyxylose
13c NMR compares, hemicellulose graft polypropylene oxide at δ 18.4,17.9 and 17.4ppm place occur new peak be-CH on graft side chain
3upper C atom, the new peak occurred at δ 67.1 and 65.9ppm place is end-CH on graft side chain
2upper C atom, the new peak occurred at δ 72.8ppm place is the upper m-CH of graft side chain
2upper C atom, the new peak occurred at δ 75.0ppm place is C atom on-CH on graft side chain, and these emerging peaks prove successfully to have synthesized hemicellulose graft polypropylene oxide.
The hemicellulose graft polypropylene oxide graft(ing) degree that the present embodiment obtains is 70%.The hemicellulose graft polypropylene oxide obtained is compared with former hemicellulose, has hydrophobicity and thermostability is high, can be used for preparing food packaging film and amphipathic sorbent material etc.
Embodiment 2
The synthetic method of a kind of hemicellulose graft polypropylene oxide of the present embodiment, comprises the following steps:
(1) dissolve: 1g is gathered the LiCl/N that seminose joins 200ml, in N-N,N-DIMETHYLACETAMIDE, at 90 DEG C of stirred under nitrogen atmosphere 5h, CL hemicellulose; LiCl/N, N-N,N-DIMETHYLACETAMIDE mass volume ratio is 4%, and the unit of quality is g, and the unit of volume is ml;
(2) react:
(2-1) step (1) gained solution is down to room temperature, adds the aluminum isopropylate being dissolved in toluene, stir 30min, wherein in aluminum isopropylate and hemicellulose, dewatering unit mol ratio is 0.1: 1;
(2-2) propylene oxide is added in following ratio: the mol ratio of propylene oxide and hemicellulose dewatering unit is 1: 1, at 20 DEG C, react 12h;
(3) solution that step (2-2) obtains is joined 90%(volume) precipitin reaction product in ethanolic soln, be precipitated thing through centrifugal;
(4) throw out step (3) obtained is dialyse 1 day in the dialysis tubing of 1000Da at molecular weight cut-off;
(5) dry: adopt lyophilize, temperature is-50 DEG C, and vacuum tightness is 300mba, time 30h.
The hemicellulose graft polypropylene oxide graft(ing) degree that the present embodiment obtains is 50%.
13C NMR(D
2O)：δ(ppm)=17.4ppm(C，CH
3)，67.1ppm(C，CH
2T)，72.8ppm(C，CH
2)，75.0ppm(C，CH)。
Embodiment 3
The synthetic method of a kind of hemicellulose graft polypropylene oxide of the present embodiment, comprises the following steps:
(1) dissolve: LiCl/N 1g polyxylose glucose being joined 80ml, in N-N,N-DIMETHYLACETAMIDE, at 110 DEG C of stirred under nitrogen atmosphere 3h, CL hemicellulose; LiCl and N,N-dimethylacetamide mass volume ratio are 6%, and the unit of quality is g, and the unit of volume is ml;
(2) react:
(2-1) step (1) gained solution is down to room temperature, adds the aluminum isopropylate being dissolved in toluene, stir 20min, wherein in aluminum isopropylate and hemicellulose, dewatering unit mol ratio is 0.5: 1;
(2-2) propylene oxide is added in following ratio: the mol ratio of propylene oxide and hemicellulose dewatering unit is 10: 1, at 30 DEG C, react 36h;
(3) solution that step (2-2) obtains is joined 92%(volume) precipitin reaction product in ethanolic soln, be precipitated thing through centrifugal;
(4) throw out step (3) obtained is dialyse 2 days in the dialysis tubing of 3000Da at molecular weight cut-off;
(5) dry: adopt vacuum-drying, temperature is 40 DEG C, and vacuum tightness is 0.5MPa, time 24h.
The hemicellulose graft polypropylene oxide graft(ing) degree that the present embodiment obtains is 60%.
13C NMR(D
2O)：δ(ppm)=17.4ppm(C，CH
3)，67.1ppm(C，CH
2T)，72.8ppm(C，CH
2)，75.0ppm(C，CH)。
Embodiment 4
The synthetic method of a kind of hemicellulose graft polypropylene oxide of the present embodiment, comprises the following steps:
(1) dissolve: 1g is gathered the Li/N that β-glucose joins 120ml, in N-N,N-DIMETHYLACETAMIDE, at 120 DEG C of stirred under nitrogen atmosphere 3h, CL hemicellulose; LiCl and N,N-dimethylacetamide mass volume ratio are 5%, and the unit of quality is g, and the unit of volume is ml;
(2) react:
(2-1) step (1) gained solution is down to room temperature, adds the aluminum isopropylate being dissolved in toluene, stir 10min, wherein in aluminum isopropylate and hemicellulose, dewatering unit mol ratio is 0.4: 1;
(2-2) propylene oxide is added in following ratio: the mol ratio of propylene oxide and hemicellulose dewatering unit is 20: 1, at 40 DEG C, react 30h;
(3) solution that step (2-2) obtains is joined 95%(volume) precipitin reaction product in ethanolic soln, be precipitated thing through centrifugal;
(4) throw out step (3) obtained is dialyse 1 day in the dialysis tubing of 3500Da at molecular weight cut-off;
(5) dry: adopt vacuum-drying, temperature is 40 DEG C, and vacuum tightness is 0.5MPa, time 48h.
The hemicellulose graft polypropylene oxide graft(ing) degree that the present embodiment obtains is 64%.
13C NMR(D
2O)：δ(ppm)=17.4ppm(C，CH
3)，67.1ppm(C，CH
2T)，72.8ppm(C，CH
2)，75.0ppm(C，CH)。
Embodiment 5
The synthetic method of a kind of hemicellulose graft polypropylene oxide of the present embodiment, comprises the following steps:
(1) dissolve: 1g is gathered the LiCl/N that 4-O-methyl-D-glucose aldehydic acid base aralino wood sugar joins 180ml, in dinethylformamide, at 80 DEG C of stirred under nitrogen atmosphere 4h, CL hemicellulose; LiCl and DMF mass volume ratio are 10%, and the unit of quality is g, and the unit of volume is ml;
(2) react:
(2-1) step (1) gained solution is down to room temperature, adds the aluminum isopropylate being dissolved in toluene, stir 20min, wherein in aluminum isopropylate and hemicellulose, dewatering unit mol ratio is 0.8: 1, the mass volume ratio of aluminum isopropylate and toluene is 1: 50, and described mass unit is g, and volume unit is ml;
(2-2) propylene oxide is added in following ratio: the mol ratio of propylene oxide and hemicellulose dewatering unit is 25: 1, at 50 DEG C, react 24h;
(3) solution that step (2-2) obtains is joined 95%(volume) precipitin reaction product in ethanolic soln, be precipitated thing through centrifugal;
(4) throw out step (3) obtained is dialyse 2 days in the dialysis tubing of 4000Da at molecular weight cut-off;
(5) dry: adopt lyophilize, temperature is-50 DEG C, and vacuum tightness is 500mba, time 48h.
The hemicellulose graft polypropylene oxide graft(ing) degree that the present embodiment obtains is 58%.
13C NMR(D
2O)：δ(ppm)=17.4ppm(C，CH
3)，67.1ppm(C，CH
2T)，72.8ppm(C，CH
2)，75.0ppm(C，CH)。
Above-described embodiment is the present invention's preferably embodiment; but embodiments of the present invention are not limited by the examples; change, the modification done under other any does not deviate from spirit of the present invention and principle, substitute, combine, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.
Claims (2)
1. a synthetic method for hemicellulose graft polypropylene oxide, is characterized in that, comprises the following steps:
(1) dissolve: hemicellulose is joined LiCl and N, N ?N,N-DIMETHYLACETAMIDE or N, N ?in dimethyl formamide, at 80 ~ 120 DEG C of stirred under nitrogen atmosphere 3 ~ 5h, CL hemicellulose; Described hemicellulose and N, N ?N,N-DIMETHYLACETAMIDE or N, N ?the mass volume ratio of dimethyl formamide be 1:1000 ~ 1:20, LiCl and N, N ?N,N-DIMETHYLACETAMIDE or N, N ?the mass volume ratio of dimethyl formamide be 1:25 ~ 1:10, the unit of described quality is g, and the unit of described volume is ml;
(2) react:
Step (1) gained solution is down to room temperature, is added catalyzer by (2 ?1), stirs 10 ~ 30min, and in described catalyzer and hemicellulose, dewatering unit mol ratio is 0.1:1 ~ 2:1; Described catalyzer is the aluminum isopropylate being dissolved in toluene;
(2 ?2) add propylene oxide, at 20 ~ 60 DEG C, react 24 ~ 48h; The mol ratio of propylene oxide and hemicellulose dewatering unit is 1:1 ~ 30:1;
(3) precipitate: the solution Jia that step (2 ?2) obtains is entered Dao Shui ?precipitin reaction product in alcohol mixed solution, through centrifugal or filter and be precipitated thing; Described Shui ?in alcohol mixed solution the volume percent of ethanol be 90 ~ 95%;
(4) purifying: the throw out that step (3) obtains is carried out dialysis 1 ~ 2 day; Dialysis tubing molecular weight cut-off is 1000 ~ 5000Da;
(5) dry, obtained hemicellulose graft polypropylene oxide; Described drying is lyophilize, temperature Wei ?40～?60 DEG C, vacuum tightness is 200 ~ 300mba, the time be 12 ?48h.
2. the synthetic method of hemicellulose graft polypropylene oxide according to claim 1, it is characterized in that, described hemicellulose be polyxylose, poly-4 ?O ?Jia Ji ?D ?glucuronic acid pectinose wood sugar, poly-semi-lactosi seminose, polyxylose glucose and Ju β ?any one in glucose.
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