f****n
发帖数: 95 | 1 我在为含氟的丙烯酸酯/丙烯酰胺类高分子寻找good solvent,发现trifluoroacetic
acid (TFA)的溶解能力特别强，很好用。可是，高分子（白色粉末）溶解于新鲜的TFA
之后溶液由无色透明慢慢变为淡黄色透明。
是不是因为TFA是强酸有所谓的发烟现象？浓盐酸就是淡黄色，因为含有少量杂质Cl2
。另外， 含卤素或含硝基的化合物容易变颜色,是少量变质导致的吗？
谢谢！
p.s.
查到有这么一句：“olutions of proteins in trifluoroacetic acid prepared in
vacuo
are clear and colourless; on exposure to air, a purple colour develops.”不
解中···
Nature 174, 509 (11 September 1954); doi:10.1038/174509a0
Anhydrous Trifluoroacetic Acid as a Solvent for Proteins
JOSEPH J. KATZ
Chemistry Division, Argonne National Laboratory, Lemont, Illinois. May 25.
IT has recently been reported1 that liquid anhydrous fluoride is a powerful
solvent for a wide variety of proteins. It has now been found that the lower
perfluoro-aliphatic carboxylic acids possess solvent properties for
proteins very similar to those of hydrogen fluoride. Thus it has been
observed that trifluoroacetic acid (m.p. – 15.6° C, b.p. 72° C.) readily
dissolves the proteins lysozyme, ribonuclease, trypsin, pepsin, crystallized
egg albumin, bovine plasma albumin, bovine plasma globulin, edestin, peanut
protein globulin, casein, zein, urease, uricase, blood fibrin, insulin,
silk fibroin, hide collagen and rat-tail tendon. Solutions in the
concentration-range 20–30 mgm./ml. of the above proteins can easily be
prepared at 25° C. Solutions of proteins in trifluoroacetic acid prepared
in vacuo are clear and colourless; on exposure to air, a purple colour
develops. Cytochrome c, hæmoglobin and catalaes are also soluble;
solutions of these iron-containing proteins are browner in colour than are
the corresponding solutions in hydrogen fluoride.
Nature, 173, 265 (1954); Arch. Biochem. Biophys. (in the press).
还有这个Sigma-Aldrich的说明：
Toxicity – Hazards – Storage – Stability
TFA is a moisture-sensitive liquid. Store in a brown bottle or amber ampul
at
room temperature, in a dry, well ventilated area away from ignition
sources.
Properly stored, this reagent is stable indefinitely. Moisture will
decompose both the reagent and its derivatives. To exclude moisture, Supelco
packages this product under nitrogen. If you store an opened container or
transfer the contents
to another container for later reuse, add desiccant. Before reuse, validate
that your storage conditions adequately protected the reagent. | h******g
发帖数: 600 | 2 聚丙烯酰胺不是能和TFA反应吗。
TFA
Cl2
in
【在 f****n 的大作中提到】
: 我在为含氟的丙烯酸酯/丙烯酰胺类高分子寻找good solvent,发现trifluoroacetic
: acid (TFA)的溶解能力特别强，很好用。可是，高分子（白色粉末）溶解于新鲜的TFA
: 之后溶液由无色透明慢慢变为淡黄色透明。
: 是不是因为TFA是强酸有所谓的发烟现象？浓盐酸就是淡黄色，因为含有少量杂质Cl2
: 。另外， 含卤素或含硝基的化合物容易变颜色,是少量变质导致的吗？
: 谢谢！
: p.s.
: 查到有这么一句：“olutions of proteins in trifluoroacetic acid prepared in
: vacuo
: are clear and colourless; on exposure to air, a purple colour develops.”不
| f****n
发帖数: 95 | 3 这个不知道啊。我是有机小白。
我使用的是poly(N,N-dimethylacrylamide),所以不担心这个反应。
【在 h******g 的大作中提到】
: 聚丙烯酰胺不是能和TFA反应吗。
:
: TFA
: Cl2
: in
|
|
