How to remove the phenolic hydroxyl group, how to remove or replace the phenolic hydroxyl group

Generally speaking. The people who ask this question are very skilled, because this can easily lead to crime.

But just ask me.

After all, you can't make it without raw materials.

Having raw materials and no equipment is equivalent to no efficiency.

It's a waste of money to get it.

Or seriously:

The phenolic hydroxyl group is carefully oxidized to quinone first, and then ammonia is used.

Made into aniline, the rest is very simple, a diazotization reaction.

Then ethanol is used. Removing n2 is all it takes.

It's dangerous to ask this question.

The list is summarized as follows (+ for reaction, - for non-reaction).

Functional group. Alcohol hydroxyl group.

.Phenolic hydroxyl group. Carboxyl.

nahco3...

na2co3...

naoh...

na...nahco3

ch3cooh---ch3coona

co2↑h2o

na2co3 ＋c6h5oh－－＞c6h5ona＋nahco3na2co3

2ch3cooh---2ch3coona

co2↑h2o

Naoh ch3cooh ch3coona h2onaoh c6h5oh c6h5ona h2o2na 2ch3ch2oh 2ch3ch2ona h2 2na 2c6h5oh 2c6h5ona h2 2na 2ch3cooh 2ch3cooh 2ch3coona h2.

Here's how to prepare methamphetamine: the detailed preparation process of methamphetamine hydrochloride.

Liquid nitrogen was injected and the experimental apparatus was flushed.

Magnesium shavings, anhydrous ether and a small iodine crystal are placed in the three-mouth flask.

Add 25 ml of benzyl chloroethyl ether solution (prepared from benzyl chloride and anhydrous ether).

It takes 30 minutes for the reaction to begin. When the reaction starts, the color of the iodine will disappear.

If the reaction does not start within 30 min, heat the thin-necked flask using a water bath at 104 degrees Fahrenheit.

From the beginning of the reaction, the remaining benzyl chloride solution must be added within 30 minutes.

While adding the benzyl chloride solution, start stirring.

The volume of the flask immersed in an ice water bath can be adjusted to control the reaction temperature.

After all the benzyl chloride solution has been added, the reaction will continue for about 15 minutes.

After this, reflux with water bath for 15 minutes.

Heat the flask with an electric heater to keep the reaction liquid boiling smoothly.

After completing the above steps, slowly add 44 g of acetaldehyde to the flask and stir constantly.

The temperature will rise, keeping it at 50 degrees Celsius for up to 2 hours.

Once completed, the imported methyl portion of the synthesis is configured as Gear 2.

Add approximately 200 ml of 40% monomethylamine in water to a 500 ml thin-necked flask.

Heat slowly to no more than 150 degrees Fahrenheit.

The bottom of the reflux condenser tube is cooled with methanol and dry ice.

The gaseous methylamine is evaporated and passed into a 1,000 ml flask for about 3 h.

What happens at this point is an exothermic reaction.

Slowly cool the container and then extract the extract with ether and evaporate dry.

The residue is methamphetamine, which needs to be converted to its hydrochloride.

Dissolve the residue in 200 ml of anhydrous ether and pass the dried HCl gas into the solution until the precipitate is no longer formed.

The precipitate is obtained by filtration and recrystallization with anhydrous ether to obtain a pure product.

Generally speaking, the people who ask this question are very level, because this is easy to cause crime, but if you ask, I will answer, after all, you can't make it without raw materials, and if you have raw materials, you don't have equipment, it is equivalent to no efficiency, and it's a waste of money.

Or seriously:

The phenolic hydroxyl group is carefully oxidized to quinone first, and then aniline is made with ammonia, and the rest is very simple, a diazotization reaction and then ethanol to remove N2 is enough.

It's dangerous to ask this question.

Sorry, revise it.

I think of one, but there are many steps, let me declare, I am not an expert, I just graduated from high school, I just came to express my opinion, I have no intention of mixing points, please ask experts for more advice.

First of all, Ni is used as a catalyst, phenol is reduced to cyclohexanol with hydrogen, hot copper is used as a catalyst, cyclohexanol is oxidized to cyclohexanone with oxygen, and then, NH3, Ni, H2 is used to turn cyclohexanone into cyclohexanone in ethanol solvent, and then, sodium nitrite and hydrochloric acid are used to form diazo compounds, and then hypophosphorous acid is added to generate cyclohexane at room temperature.

After that, it is brominated with NBS, then eliminated, and repeated twice to form benzene.

I'm adding a similar method, inferior, in order not to repeat: oxidation to quinone, Clemmensen reduction, PD dehydrogenation. The end of the sophomore year of high school, hehe.

And I would like to remind you that this chemical conversion is certainly not economical. I have a yield greater than 100% method that you like. It is to sell phenol and exchange it for some benzene, or directly barter.

More than 100% guaranteed. I think benzene is cheaper than phenol, after all, it is made from it.!! Organically, I probably don't think about such useless chemical transformations.

Upstairs, phenol is supposed to be more expensive than benzene, but you can't guarantee that all phenolic hydroxyl compounds are more expensive than the compounds that are taken off and turned into hydrogen!

Actually, I don't quite understand the sensitivities, so guess what. It's not going to be the kind of drug you're going to make, it's a drug, hahahahahaha!!

It's pure speculation, please don't laugh!

Can the hydroxyl group be converted into a sulfo group first, and then hydrolyzed with dilute sulfuric acid?

Naphthol is easier to do, and ammonia can be used to react with ammonium sulfite to produce naphthalene amine. Then naphthylamine is diazotized and reduced to naphthalene with hypophosphorous acid.

The content of organic chemistry in college ha! Add a weak alkaline solution of acetaldehyde to phenol, the temperature is about 70 degrees, and finally benzene can be generated.

Phenol first ammoniatolyzed into aniline.

It then reacts with sodium nitrite to form diazobenzene.

Then use alcohol to remove the diazo group, and it's OK.

However, this reaction is really meaningless, and no one should try to do it in one step.

It's such a professional problem, I can't solve it for you as a high school student.

You'd better be specific, or you don't know what the restrictions would be if there were other groups.

If you can't say it, go to Wikipedia, where it's very complete (it's up to you).

Phenolic hydroxyl removal can be pre-halogenated.

It is then formed into an amino group, and it is eliminated in the form of diazo.

Phenolic hydroxyhalogenation can be used with phosphorus oxychloride.

and phosphorus pentachloride, and thionyl chloride and the like.

Hello, the hydroxyl group on the phenol is very difficult to get rid of, because there are large bonds on the benzene ring, which makes the phenol itself have a p- conjugation, so the c-o bond is very strong. Therefore, it is difficult for the C-O cleavage reaction to occur on phenol.

However, if high temperatures are used, the C-O may break under the conditions of catalysts and strong oxidants, but there will be many side reactions.

Don't know what the purpose of your dehydroxyl group is.

Phenol reacts with aldehydes (e.g., formaldehyde) to form water.

Phenol undergoes halogenation reaction with halogens such as bromine water.

Phenol undergoes a displacement reaction with sodium hydroxide.

Hope it helps!

It is polycondensation. The C=O bond in formaldehyde is broken, and the remaining -CH2- subplaces H on the hydroxyl ortho-c C to form a network structure. The broken O and the substituted H combine to form H2O. It is a polycondensation reaction.

The removal of phenolic hydroxyl groups can be halogenated first, then into amino groups, and then eliminated in diazo. Phenol hydroxyhalogenation can be used with phosphorus oxychloride and phosphorus pentachloride, and thionyl chloride can be used for the like, you can check the book.

The alcohol hydroxyl group is eliminated first, then the phenolic hydroxyl group is removed, and then the alcohol hydroxyl group is added back to the alcohol hydroxyl group.

Can you describe the structure of phenolic resin? I probably remember benzene and formaldehyde.

Then it is benzene that loses h on the formaldehyde and opens the double bond connection.

Phenolic hydroxyl refers to the hydroxyl group on the benzene ring, do you mean to remove the hydroxyl group on the benzene ring in the resin or to neutralize the acidity of the hydroxyl group? Or does it mean the removal of free phenols "above" (i.e., on top of the resin's aqueous liquid)? First of all, you need to be clear about what you want to do, so that others can understand it and discuss it together.

Phenolic hydroxyl group protection I have used in my experiment, using potassium carbonate, dimethyl sulfate as a participant, acetone as a solvent, 90 reaction for 4 hours, you can protect the phenolic hydroxyl group into methoxy group... As for the method of deprotection, I haven't done that step yet, but I saw in the book that you can use HBR (40%), low temperature reaction, etc., but it is best to have someone who has used it in person, so as to give substantial experience. I'm also waiting for a way to get out of protection...