Cum pot cristaliza o soluție apoasă de mef gata preparată folosind NaCl dacă nu am avut făină inițial? Să zicem că am o bază de mef în diclormetan și am de gând să o acidific în exces de apă 135 ml la 100 mef, în timp ce dizolv mef în apă - nu pun mef în făină, ci imediat în apă
În ce etapă să adaug NaCl și în ce proporții. Conform experienței superioare, autorul indică 23 de grame la 100 de grame de mef, dar el are 100 de grame de mef dizolvate în 100 ml de apă. Iar oxidarea mea are loc la o cifră de 135 ml per 100 g de produs.
Cât timp se formează cristalele în metoda soluției saline de NaCl? Ce fracții de mărime se obțin? cât timp trebuie păstrat produsul în congelator? Timpul de expunere influențează dimensiunea cristalului?
pe dcm nu se poate face așa, trebuie să utilizați apă în procesul de acidificare și apoi să utilizați, de exemplu, ipa pentru a începe imediat procesul de cristalizare. Naci nu e nevoie deloc, e o prostie. și nu poți îngheța pentru că cristalul nu va ieși decât sub formă de praf de sticlă și cristal
Brine cristalisation grom yesterday - everything happen in about one hour. But its recrystalisation of 3cmc. At the same time i maked 3 other kind of crystalisation. The biggest crystal (yes one big crystal) is in only vodka. The most beautifull is on 1 ml dh2o/1g powder, boiled few minutes in atomic generator and later i used only ceramic lamp
Oh nice, if you break it up more it will help you remove the colouration of the crystal otherwise the acetone won't be able to penetrate the solid mass of that crystal. You could probably get that white if it was broken down more.
My latest crystal, from a failed batch which i put in a beaker and used as container to drip remainders of solvents, acids andsoforth. After some weeks i needed the beaker and while cleaning it, i found these.
Now i want to make these on purpose but how... without using loads of beakers as a waste bin
Good evening science partners,
Evaporated 4mmc from watter solution and I wasnt happy in crystals colour and shape. I put watter/crystals 1:1 to recrystalize. But its going so fast. In one hour i got crystal film on top of solution in beaker, so evaporation its not possible in that point. Now I see that there is formed crytsals on walls and bottom. So i cut that film a little bit to see what inside, and there is much liquid. What Im doing wrong in these steps?
1:1 ratio means you used hot water which you then allowed to cool down. This process crashes out a lot of solid matter, but the crystals are small, tiny and needle-like in fact. If you can slow down the cooling to give them more time they'll be larger. Once the solution cools down, only about a half of the crystals are formed and the other half remain in the solution. You can strain the crystals and let the remaining mother liquor to evaporate further still to grow more crystals.
ohh good point, remember one post posted. Closed crystalization beaker, ar put under the pilow too keep warm. So I put in the towel and put under the 250w lamp ~34C. after 12h I will tell results. I need to get hard crystals of mef. If you know more methods to try please tell i will try
Result of 150g mmc 1:1 watter. 80celcius solution, put in towels at ~24c. after 12h got ~38g crystals like these, mother liquid must be evaporated to get rest mmc. I dont know what i did, becouse second try of this method was not succesful at all. But i Want to get crystals like these any advises?
You need to understand the theoretical yield (how much acid you used) and keep the same proportions for the product, water and temperature so that the result is stable.
Okay.. Sometimes its differs, becouse I cant achieve full control of reaction(time to time its going better), but mostly for 100g bromo 40ml 28%hcl
But what does crystallization have in common with recrystallization. I already have white, no odour crystals but suggar size and want to make bigger - "like flower". today i got it again flower like. but from 80g got ~20g flowers then put to fridge and all my "flowers" now in the tiny snow flakes
Then simply dissolve the solution in the saturated solution of h2o( they are alredy purified once) and perform gradual crystalisation.
You can use the method which will grow them "more attractive" but it takes 1-3 weeks. You can heat solution to 80c and gradually decrashe it to the minimum but do use 3 ml of h2o per 1 g of 4mmc, they will probably grow bigger.
I do 1st 75% of mass 1:1, then I wait till its oversaturated to leave it in proper moment
oversaturated - the solvent reached its max temp, it cant dissolve more so it doesnt dissolve it; thin layer in the top will appear, its the moment to move it into the oven.