Raoul Kessels
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Is polylactic acid (PLA) soluble in ethylacetate?
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4 votes

D- and L- polylactic acids come from both enantiomers of the monomeric lactic acids. There will be no difference in solubility between both polymers. Besides, lactic acid is normally produced by ...

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What changes does zinc chloride undergo when ‘fusing’ on an atomic level? How does this influence reactivity?
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4 votes

One purpose is to eliminate water as @Waylander has already pointed out. Another is to have a clean crystal surface. Aging is a common process of crystals. The surface is transformed slowly. The ...

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Difference between tendency of benzene and thiophene to undergo sulfonation
4 votes

In the chapter Aromatic five-membered ring heterocycles with one heteroatom in Organic Chemistry by J. William Suggs (2002) the following explanation can be found (pp. 403-404) which summarizes the ...

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How is the cavity of a cyclodextrin chiral?
4 votes

It is because the constituent glucose molecules are chiral. In the image you can see that all the $\ce{CH2OH}$ groups in the center are out of the plane (towards you). These groups are on the upper ...

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If melting points and freezing points are the same, what state is pure equilibrium?
4 votes

At the melting point there is a change of state. This means that solid is transformed in liquid or viceversa. For this process you need energy which is supplied or withdrawn in the form of heat. The ...

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Why is it aqueous and ethanolic conditions for nucleophillc substitution of cyanide ion with benzyl chloride?
3 votes

The cyanide ion is a very good nucleophile and reacts readily with benzyl chloride. The problem is that the cyanide salts are soluble in water, while the benzyl chloride is not. Therefore, ethanol ...

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How to quickly diffuse a dye through still water
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3 votes

If you want a homogeneous distribution of dye, you will have to stir the solution. If you want to use electrophoresis, you need a charged dye. Azo dyes used for hair coloring have colour and charge,...

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Is graphite a better lubricant on the Moon than on the Earth?
3 votes

Graphite, like most solid lubricants, has a layered structure which makes it a good lubricant. The atoms of a layer are strongly bonded to each other, while the interlayer (van der Waals) forces are ...

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Can sucralose form a syrup?
3 votes

Syrup is just a very concentrated solution of sugar. Because of the high concentration (for instance 65% w/w for USP Syrup, the concentration that avoids bacterial growth) the viscosity increases, ...

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Major product in Reimer-Tiemann Carbonylation
3 votes

You are right in that the $\ce{OH}$ is the main director, especially in alkaline media. The para position is preferred over ortho because it has less sterical hindrance. Therefore, the major ...

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organic spectroscopy: n-phenethylacetamide base peak ion
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3 votes

Assuming electronic impact, the most electronegative atom will loose an electron and remain positively charged. Amides typically undergo a McLafferty rearrangement. In this case, the rearrangement can ...

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Function of water and the need of two barrels in a biogas Generator
3 votes

The reasons are as follows: The inverted barrel must be full of water. Then, when methane is formed, it will displace the water and the barrel will start floating. Methane does not do anything with ...

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Formaldehyde (37%) storage
3 votes

In the cold some paraformaldehyde (formaldehyde polymer) or trioxymethane (a cyclic condensation product of three formaldehydes) may precipitate. It will depend on how much methanol has been added to ...

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How to find chemical market value
3 votes

Until 2005 or 2006 the best source was Chemical Market Reporter. It had the form of a newspaper and was edited once a week. The last pages listed market prices for commodities, some speciality ...

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How could I easily quantify the amount of EGCG in a sample of green tea?
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3 votes

To analyze specifically this component, you will have to use HPLC. In case you can use a more generic approach, you can analyze the total phenolic content with the Folin-Ciocalteu method. The Folin-...

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How to remove nitrose gasses from ozone gas mixture?
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3 votes

There is no need to use caustic since $\ce{NO2}$ reacts with water itself. As per [1] it is even better absorbed in water than in $\ce{NaOH}$. Ozone is soluble in water depending on the ...

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Redox potential of a lead–acid battery
3 votes

The potentials depend on the form of the compounds. It is true that in solution $\ce{Pb^{2+} (aq) + 2e^- -> Pb (s)} $ is -0.126 V. But in the case of a battery we have: $\ce{PbSO4 (s) + 2e^...

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Is the ethyl cation really more stable than benzylic and allylic carbocations?
3 votes

As per Jerry March in Advanced Organic Chemistry, the stability order of the cations is benzyl > allyl > t-butyl as expected due to resonance. The ethyl cation does not even exist because it is so ...

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Why is ortho-hydroxybenzoic acid more acidic than its para-isomer?
2 votes

The intramolecular hydrogen bond in ortho-hydroxybenzoic acid between the $\ce{COO-}$ and the -$\ce{OH}$ groups forms a six membered ring. Since this structure is very stable, the deprotonation of ...

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What's the difference between FFKM and PTFE?
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2 votes

Teflon (PTFE) and Kalrez (FFKM) are different polymers. PTFE is made from tetrafluoroethylene, and contains only carbon and fluor. The material is stiff. FFKM is made from tetrafluoroethylene, ...

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What are standard controllers for automatic pH control?
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2 votes

Automatic pH control is not that easy as is shown by the fact that automatic titrators, the equipment that you want to build, are relatively expensive. Besides titration, automatic titrators usually ...

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Are crown ethers "recycled", typically?
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2 votes

Crown ethers are typically not recycled because they remain in the organic phase where normally also all the byproducts are (so the purification is very complicated) and they are still complexing the ...

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Normal Phase TLC using ethyl acetate as eluent
2 votes

TLC is only about polarity. Since all three compounds share the benzoic acid functionality, we only have to consider the rest. Then we have three compounds: $\ce{R-OCOCH3}$, $\ce{R-OH}$ and $\ce{R-H}...

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Solubility of oxygen in liquid hydrogen; is anything near 1:2 (molar ratio) possible?
2 votes

It would be the other way round. Since the oxygen is the first to liquify, it would be hydrogen dissolved into liquid oxygen. In this article they show the following calculated vapour liquid ...

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Using acetone instead of acetonitrile on reverse-phase prep-HPLC
2 votes

If you want to go completely green, you should use ethanol. In many sectors it is considered the only green solvent (except for water of course). Then, to be really green, you should make sure that ...

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Why does the isoelectric range decrease as an Alanine chain grows longer?
2 votes

It is because of the inter- and intramolecular associations that occur. In Ala, the first loss of a proton forms a two point intermolecular association which is very favourable. Since the ...

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Using drip extraction, how much caffeine is extracted from coffee as a function of the amount of water used?
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2 votes

Caffeine has a solubility in water of 20% at 80 $^\circ$C, while the coffee has between 1 and 4% caffeine. That means that you have more than enough water to extract all the caffeine in the coffee. ...

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Methods for dissolving Scotch/Kaptop/etc. Tape for Electron Microscopy?
2 votes

Kapton is a polyimide: It contains an $\ce{N}$ substituted phtalimide as a substructure. This kind of compound is used in the Gabriel synthesis to make primary amines. The synthesis is very ...

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Soxhlet extraction condenser - addition of compound to refluxing setup
2 votes

In my opinion the intention is to have a very slow addition of the reagent to the hydride. The compound is dissolved in ether, so a Soxhlet is of no use since it is for solids. What they are ...

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Why do orthoesters react with Grignard reagents, but acetals and ketals don't?
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2 votes

Grignard reactions are performed in ether or THF. There you have only one -OR group on a carbon and, since it is the solvent, it is not reacting with it. This shows that not always a -OR group is ...

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