功能性PEG的合成 - 实验交流 - 生物秀
标题: 功能性PEG的合成
摘要: [功能性PEG的合成] 我想合成一系列功能性修饰的PEG，如a-羟基-w-羧基聚乙二醇，在网上看了下报价，一克要1500元，哪位大哥能提供的合成思路呢 关键词:[羟基 功能性 羧基 环氧乙烷 羧酸 色谱 重结晶]……
我想合成一系列功能性修饰的PEG，如a-羟基-w-羧基聚乙二醇，在网上看了下报价，一克要1500元，哪位大哥能提供的合成思路呢回复a-羟基-W-羧基是用在引发的时候用含羟基的羧酸的钠盐（比如,Na-O-CH2-CH2-CH2-COONa），引发环氧乙烷的聚合。回复我们已经有了PEG2000，我们现在合成的路子是先得到两端都含功能团的混合，再采用柱色谱的方法分离，但分离的效果不是很好，而且收率很低，只有25%左右，有没有重结晶的办法可以分离的啊回复用重结晶肯定不行！
我们已做过多次尝试，想把成本降下来，但最终都必须过柱子分离。
我们有现货，如急用可联系我们。回复我现在也在做这方面的东西，想问你一下，你们现在用的过柱分离溶剂的是如何配比的？我现在也在分但效果不好回复
a-羟基-W-羧基是用在引发的时候用含羟基的羧酸的钠盐（比如,Na-O-CH2-CH2-CH2-COONa），引发环氧乙烷的聚合。 请问有相关的文献吗？回复
请问有相关的文献吗？ Preparation of .alpha.-carboxylic-.omega.-hydroxyl polyethylene oxide HOOC--(CH.sub.2).sub.3--O--
(CH.sub.2CH.sub.2O).sub.n--CH.sub.2CH.sub.2OH
Intitiator: 4-hydroxy butyric acid-sodium/potassium salt (K/NaOCO--CH2CH2CH2OK/Na) Synthesis of
the polymer is involved three steps: (1) Initiation of ethylene oxide monomer (2) Propagation of ethyene
oxide monomers and (3) termination of polymerization.
Polymerization of ethylene oxide was carried out in a high pressure reactor (Par reactor) equipped with a
magnetic driven mechanical stirrer. The reactor was bubbled with dried argon.
Initiator was prepared separately in a three necked 1 L flask equipped with magnetic stirrer and a condenser
with three way stopcock. 4-hydroxy butyric acid-sodium salt (5.7 g 0.045 mol) obtained from Fluka
Chemical Co was used as received (it contain <0.5% water) added to the flask followed by addition of freshly
cut potassium (1.8 g 0.046 mol). After addition of the solid content the flask was evacuated followed by
pressurizing (30 psi) with argon. Dried tetrahydrofuran (THF) 400 ml was added and the solution was
refluxed for 12 h. A heterogeneous solution is formed. This solution was transferred to high pressure Par
reactor under a flow of argon using 12 gauge double tip stainless steel needle. The reactor temperature was
lowered to -10.degree. C. Freshly distilled ethylene oxide (50 ml) (distilled over n-butyllithium) was added
using stainless steel capillary. The solution was stirred at 50.degree. C. for 24 h. The reactor temperature cool
to water bath temperature and the reactor content was poured into a glass beaker containing HCl (5 ml of
35% aqueous solution). A slight yellow color solution is formed with the precipitation of salt (KCl). Solution
was filtered and the filtrate precipitated in cold 2-propanol containing 20% hexanes, giving the desired
product as a light yellow precipitate which is dried in vacuo overnight. Yield 38 g (86.3%).
In an Erlenmeyer flask equipped with a magnetic stir bar, obtained polymer from the preceding step was
added to 500 ml distilled deionized water and stirred to dissolve followed by addition of dichloromethane to
extract the polymer and to remove the unreacted initiator and residual amount of salt present. The solution
was washed with deionized water two times than the dichloromethane solution was concentrated in
rotavapor. The product finally reprecipitated in cold diethyl ether. The product was dried in vacuo
overnight. Yield: g, 88%. .sup.1H-NMR (CDCl.sub.3) 2.35 ppm (m, --CH2 2H adjacent to COOH), 3.60
ppm (s, PEG backbone, 77H), 4.37 ppm (t, OH, 1H). .sup.1H NMR spectrum is reported in FIG. 1.
Size exclusion chromatography (SEC) was carried out on a Varian liquid chromatograph equipped with a
refractive detector. Three columns from Supelco (G00 HXL) were used with THF as the
eluent. The columns were calibrated with monodisperse polyethylene glycol standards. The molecular weight
and the polydispersity indice were calculated. The SEC analysis of the product indicating Mn of 440 MwMn
1.16. The SEC trace is reported in FIG. 2. The value calculated from H NMR indicates Mn 1070. This
indicating some interaction of the heterofunctional PEG with the packing materials of the column that
resulting the retardation of the elution therefore underestimating the molecular weight of the polymer.回复北京凯正生产多种PEG修饰剂
目前生产NH2-PEG-COOH也是采用色谱分离,这也就是价格比较昂贵的原因.回复上述方法实际是有一些问题的，主要是官能化度不高！
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