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d*******s
发帖数: 1548 | 4 现在的问题是原料不溶于DCM或chloroform， 但溶于醇 |
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b******3
发帖数: 62 | 6 Try NaI in HOAc at 130C and up. Good luck. |
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j*********5
发帖数: 6221 | 8 或者直接用HI，在压力瓶里100度一天一夜
或者水里用AlCl3，回流他一夜，不信脱不掉甲基 |
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p******1
发帖数: 1388 | 9 别这么说....我周五刚刚被组里的美国傻女人投诉了, 因为实验室味道大....顶头上司
找我谈话了...
哎, 可能工作要保不住了, 因为跟她积怨已深...味道大,不过是个借口而已....顶头上
司是个混混, 非美国人. 见了美国人, 哪怕是个实习生, 都屁颠屁颠的... |
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s*******h
发帖数: 3731 | 10 啊，你还做实验啊。。。
不是说工作了，成功人士都坐办公室，cuticle。。。矬鸡才做bench work么？
不像我们千老，就是把头伸到hood里，没日没夜的。。 |
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p******1
发帖数: 1388 | 11 谁这么造谣的? 连Principal Scientist 都要亲自动手的...
但foumulation 那里, 有些老资格的, 只是查查文献指导手下的做.. |
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s*******h
发帖数: 3731 | 12 principal算几毛的？要混多少年才能混上？ |
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t**n
发帖数: 4365 | 15 DMSO萃取，headspace-GC-FID检测不行吗？
择？ |
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d****i
发帖数: 360 | 16 Please help me with this paper! Thanks!
Effect of solvent on reactivity and basicity: aminolyses of p-nitrophenyl
acetate in H2O and in DMSO†
Ik-Hwan Um, Eun-Ju Lee, Sang-Eun Jeon
Journal of Physical Organic Chemistry
Special Issue: Organic Reactivity Special Issue
Volume 15, Issue 8, pages 561–565, August 2002 |
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w***m
发帖数: 3 | 17 用甲基碘季胺化含有多个三级胺的分子，反应后溶于DMSO-d6测碳谱，除了溶剂峰无法
得到任何信号，请问有经验的同学帮忙看是什么问题 |
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R*****U
发帖数: 241 | 18 估计是溶解性，我做过单季胺化，dmso还可以，但是polymer以后就不溶了 |
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s****2
发帖数: 4569 | 19 convert O-phosphorylethanolamine into its tributylamine salt, it will
dissolve in DMSO or DMF, even MeOH. |
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n**r
发帖数: 103 | 20 非常蠢的问题， 这个脂化反应，可以在DCC（EDC)和DMSO 反应进行吗？ |
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c***x
发帖数: 1990 | 21 (TMS)_2 S 这个东东是不是跟乙醇也反应啊。
谢谢各位啊
注 _2是下脚标 |
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d******y
发帖数: 121 | 22 建议先去读一下MSDS，这玩意又臭又毒，见水汽就反应放出硫化氢。。。。。最好在
glovebox里面用，否则后果自负。。。。 |
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k****x
发帖数: 2751 | 23 可以，我以前经常遇到
一般是放些DTT还原回来 |
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S*********0
发帖数: 982 | 25 normally less than 2%. it depends |
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w******i
发帖数: 736 | 27 非常感谢！
我已经试过DMF了，似乎能溶解一点；
DMSO我也考虑过，但是它的氧化性是否强到能够将二价铁氧化成三价呢？
NMP我都暂时不知道是什么东西，呵呵。 |
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K**********n
发帖数: 1197 | 28 学术界珍稀有限的原版外文资料，
Remote Mind Control Technology
Reprinted from SECRET AND SUPPRESSED: BANNED IDEAS AND HIDDEN
HISTORY, edited by Jim Keith, $12.95, available from
1-800-680-INET.
There had been an ongoing controversy over health effects of electromagnetic
fields (EMF) for years (e.g., extremely low frequency radiation and the
Navy's Project Seafarer; emissions of high power lines and video display
terminals; radar and other military and industrial sources of radio
frequencies and micr... 阅读全帖 |
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d****n
发帖数: 237 | 29 我现在已经将N, N-dimethylaminoethyl methacrylate (DMAEMA)
接枝到PVDF上，本来是想把它溶到一种溶剂中，然后刮膜。但是现
在遇到了麻烦：我一共试了NMP,DMF，DMSO和DMAc，但是在大约10%
的浓度时候都是形成了凝胶，（共聚物接枝量经元素分析大约12%），
太低是根本形成不了膜。
各位给个意见，谢了先。 |
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p*****x
发帖数: 68 | 30 we have PS, PSS and PEO, none of them dissolves.
thanks. |
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b**s
发帖数: 589 | 31 PEO can not be dissolved in DMF? impossible
DMF is a good solvent for many polar polymers : nylon, PU, PEO...
use a little bit of heat, try again |
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c****n
发帖数: 134 | 33 I am preparing amphiphilic block copolymers: polyisobutylene-b-poly(vinyl
alcohol).
It is expected that the block copolymers is water soluble when the PIB segment
is short enough, so I can get water soluble surfactants.
however when DPn of the PIB segment is 50 or even 15, and the DPn of PVA is
200-260,
the block copolymers are not soluble in water.
when I use DMSO (a good solvent for PVA), the block copolymers are dissolved.
Any comments on this? Thanks a lot. |
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c****n
发帖数: 134 | 34 not PIP but PIB.
since the diblock copolymer is soluble in DMSO,
I have checked the structural integrity by NMR.
and----the homoPVA prepared in similar way was soluble in water.
is |
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c****n
发帖数: 134 | 35 no.
I used both poly(tert-butyl vinyl ether) and poly(tert-butyldimethylsilyl
vinyl
ether) as precursors to pva, since living polymerization of Poly(vinyl
acetate) is not easy. (I need to prepare polymers with low PDI).
the samples are soluble in DMSO at room temp.
but refluxing water failed to dissolve them.
PVA |
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c****n
发帖数: 134 | 36 Thanks a lot guys.
Chenchuan is right. DMSO is a better solvent for homoPVA, since PVA dissolves
much faster than in water (as I observed). One more fact:
polyisobutylene-b-poly(methyl vinyl ether) is soluble in water when DPn of PIB
is 50 and DPn of PMVE is 260. (PMVE is water soluble). Seems two factors work
together resulting the insolubility of the PIB-PVA in water: "This additional
kind of long range
orderness (from PIB) will make it more difficult to be attacked by solvent";
water is weak |
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a***n
发帖数: 578 | 37
dissolves
PIB
work
additional
of
No. what I meant was after you get rid of DMSO from your polymer, the polymer
will be soluble in water again. Anyway, just a guess. if wrong, then forget
it.
interesting
not.
range
said
hydrogen |
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c****n
发帖数: 134 | 38 does one block have to be "water" soluble?
Is it ok if it is "methanol" or "DMSO" soluble?
I just synthesized a block copolymer: one segment is soluble in hexane, the
other segment is soluble in methanol. The block copolymer is soluble in
methanol. Wish to know if it has some application. Thanks! |
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s****e
发帖数: 2934 | 39 大家平时用什么氘代溶剂啊？帮别人问一下，懒得查了。分子量很低的话用什么，分子
量高的呢？用氘代水看不到PEO—OH上的氢吧？可以用水峰来做内标吗？用DMSO可以吗
？THF老贵了。还有如果用甲醇的话不会像水一样有exchange的问题吧？现在他手上2个
样品一个
CH3O－PEO－OH，一个磺化端基的PEO（不含hydroxyl了）
这个磺化的PEO不能用CDCl3了吧？（分特这个问题不该问，该让这老兄自己去试） |
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y****o
发帖数: 4 | 42 get rid of the hydrogen-bonding between your polymer and the column
By the way, how to change the filter before the column? |
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p****e
发帖数: 40 | 43
谢谢先，不过不太明白你的问题，也可能我用的仪器比较土，没有附带过滤系统，总是
自己先把样品滤好再进样的。
那为什么用一般普通溶剂的时候不用加LiBr?
要是为了消除高分子和柱胶可能会有的强氢键作用的话，那其它溶剂不是一样会有这个
问题，也需要加盐进去吗？很少见啊。 |
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p******4
发帖数: 38 | 44 To minimize the intermolecular force, not only the hydrogen bonding. You
will see tailing without the salt. Then the molecular weight calculation is
unreliable.
For safety issue, it has a precolumn or filter before the columns.
In order to change the filter, you can first switch off the temperature
controller for the columns. Until ambient temperature, low down the flow
rate by 0.1 one step until the pressure is stable(eg 1.0-0.9-0.8-0.7...).
When the flow rate is zero, use tools and get the fil |
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i***y
发帖数: 190 | 46 yes, this precolumn, aka guard column, can be washed by reversely connecting
into the system, at least i did it this way.
is |
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p******4
发帖数: 38 | 47 LiBr is not necessary in all the cases. |
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p*******o
发帖数: 166 | 48 大侠们有做过溶液法制备高分子薄膜（100微米左右）的吗？我正在干这样的活儿，但
是没有经验，所以照着老板的要求做：先在50度下真空24小时，然后每隔2小时升温10
度，直到150度，期间保持真空，最后在150度下再真空24小时。对了，溶剂是DMSO，我
总觉得这样很浪费时间，能否直接升到150度，真空24小时？老板是个谨小慎微的人，
他总担心有一个溶剂分子留在薄膜里，从而会影响某些性能。。。
所以想请教大侠们，是不是有必要按这个程序制膜？请解释一下，我好用来说服老板，
多谢！！ |
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b**********e
发帖数: 531 | 49 the film should be <100nm if not stable under tem, you can try carbon
coating on the sample section on the Cu mash.
diamond is better than glass, however before you try diamond you can first
try water+glass if your film is stable in water
cryo cut you need to use half water + half dmso
you need patience + luck |
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d****n
发帖数: 237 | 50 用硫酸磺化容易交联。
今天翻了翻自己的论文，曾经用DMSO作为溶剂进行过NaSS的接枝共聚合ATRP。 |
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