Making Phenolphthalein (a common pH indicator)

In this video, phenolphthalein is synthesized by the condensation of phenol and phthalic anhydride. The phenolphthalein is separated from starting materials by several washing steps.
In theory you can also just extract the phenolphthalein from the reaction mixture using NaOH solution. This will pull out the phenolphthalein as well as the phenol. Then when the phenolphthalein is crashed out, the phenol should stay in solution. Then recrystallize. Much faster method.
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Nile talks about lab safety: • Chemistry is dangerous.

[@RMoribayashi]

My dad was a chemist and way back in the 1950's one of his collegues spiked the coffee with phenolphthalein as a practical joke. He probably wouldn't have gotten fired except he was off by at least one order of magnitude and shut down the lab.

[@haikalt.9279]

RMoribayashi i dont understand ,would u mind xplain it?

[@RMoribayashi]

Phenolphthalein is a powerful laxitive. The idiot underestimated just how powerful and put too much in their coffe. Not a funny joke. It sent several of his collegues to the hospital with severe gastrointestinal pain from explosive diarrhea.

[@wjthomas8186]

Nova Calisthenics he put ten times as much as he should have for a harmless prank.

[@sakelaine2953]

@Bless Gillette It could have killed anyone who drank the poisoned pot of coffee. Dehydration from severe diarrhea is not a joke.

[@buckstarchaser2376]

@@sakelaine2953 But does it give the diarrhea that lovely purple color? It's so pretty that it would certainly take the edge off of the agony.

[@hadinossanosam4459]

0:43: look at the magnet."I WANT TO STIR IT! Come on!!! HNNNNNNNG!" 0:48:"FINALLY!!!"

[@hgmercury7279]

50th like :D

[@carlmcalduff1191]

150th like :D

[@thefountainpendesk]

155th like :D

[@nocosttoogreat]

168th like :D

[@stumblingdeth83]

It finally believed

[@jacobstephens6937]

Can you show us how to make dihydrogen monoxide?

[@NileRed]

+Jacob Stephens I am not sure. I hear that stuff is dangerous!

[@science7089]

+Nile Red 100% of people who drink it DIE!

[@hoggif]

+Jacob Stephens Most chemists avoid that. It known to be a very dangerous synthesis where lots of accidents and explosions are known to have happened. On large scale lots of people have also died after falling into a large container of the product!

[@EarlofDestruction]

Inhaling it is very dangerous. Many people die because of that.

[@theLuigiFan0007Productions]

Why would anyone want to make dihydrogen monoxide! I'v heard it can cause a number of horrible things to happen, besides the reasons already mentioned. It can seize and destroy machinery, has been found in every cancer cell, causes electronics to fail in horrible ways that may lead to electrocution and can be blamed for about 6.1% of all deaths each year!

[@whysa4]

Have a recollection from school in the mid 1970's that there was one kid who had a reputation for helping himself to other peoples food etc. To pay him back a tempting can or bottle of juice was left unattended but that had been dosed with Phenolphthalein borrowed from the science lab due to it's knowm lacative properties.

[@TheTdw2000]

That's why I always add a few pellets of lye to my drinks just to make sure

[@oni8337]

@@TheTdw2000 don't overdose on lye either lol

[@sirloyn5044]

I am new to your channel and I just want to say I love your content! That being said, If I could change one thing about your videos it would be to add annotations at the beginning of your video. You mention that you have shown where to get DCM in a prior video but no mention of which video or where to find it. You could definitely increase the number of views you get simply by linking to your past videos. If that's not something you're interested in it would at the very least make your videos overall more informative.

[@NileRed]

Sirloingaming I understand what you mean! I should do that.

[@ללאכותרת-ט8ל]

After that, making Thymolphthalein and Bromothymol blue will be great!

[@Prchemist06]

Can we use acetone instead of DCM

[@LightAndLiving]

It turned brown, because leftover phenol reacted with oxygen. The same can happen if you synthesise paracetamol

[@arunavachakraborty4565]

It's react with HCl..cl make it brown..not oxygen..it's react with HCl how the hack u got oxygen?

[@Shelleloch]

@@arunavachakraborty4565 Oxygen in the air alone is enough to react with the phenol.

[@arunavachakraborty4565]

@@Shelleloch it's air tight .duh

[@rhythmjain5639]

@@arunavachakraborty4565 I don't think if you heard correctly, but he said that it turned brown after letting it dry overnight.

[@aiden359]

All about that red cabbage indicator

[@kbrod666]

Added to a coffee pot in the teachers lounge caused an interesting reaction

[@spankyjeffro5320]

While I'm not a chemist in any degree, your videos are pretty dang interesting. :)

[@SerGrell3Reaper]

the color that made is gorgeous at 3:15

[@tacodrake95]

Your separatory funnel looks like a beet at 3:20

[@chromiyum6849]

You mean beetroot the vegetable?

[@definitelynotyuribezmenov7611]

@@chromiyum6849 yes

[@Backyardmech1]

I remember years back being told about checking fuel bladders in aircraft with the stuff. Filling the bladder with ammonia and covering it with phenolphthalein to indicate leaks.

[@willemschipper7736]

What was the percent yield?

[@tensortab8896]

Methylene chloride has an exposure limit of 25 ppm, at which point supplied air respirators are required. I think you should include a recommendation that adequate ventilation be used or you need an SCBA (air tank respirator). Methylene chloride creates the same physiological effects as carbon monoxide.

[@erwinrommel9509]

Tensor Tab work in fumehood 😀

[@1412-kaito]

One of the most useful video . For titration especially

[@ColinRies]

Another interesting thing to do with my phthalic anhydride. Also somewhat funny that the resorcinol used for the fluorescin is just phenol with an additional hydroxy group.

[@herbslab]

wow, you are on a roll. great videos, keep em coming! thank you

[@kennettrosario2224]

Is it possible for you to show us how to extract mercury from cinnabar?

[@ColinRies]

There's a video now

[@Backyardmech1]

Reminds of potassium permanganate.

[@goharkhan7005]

very well explain every thing excellent work

[@YouMockMe]

Homemade laxatives.....nice

[@Areare349]

I have to prepare this experiment for my class soon 😭 lol, how am i suppose to make that in 45mins 🙈😂

[@judges69]

Excellent Video, thanks.

[@RMoribayashi]

There used to be a laxitive that was nothing more than chocolate with phenolphthalein added. Many children learned not to get snacks out of mama's handbag the hard way.

[@ivanovalle9764]

Can you show how to clean separatory funnels after working with dyes like this ?

[@minhnguyen475]

I wish i could’ve done this in my organic chem lab.

[@moathalmasri5832]

Thank You vert much! very useful video. Would you please list few recourses for this EAS reaction. Thanks!

[@maiphuong3192]

Why did you use DCM, some document use acid acetic pH=7 to crystallize and how to recrystaling phenolphtalein?

[@avaritiabaritia]

1:38 how is he stirring it?

[@ilovesheen7446]

Avaritia black magic

[@virginiagwen6523]

Is there any other method other than vacuum drying?

[@akhilthechemist]

Can we make thymolphthalein by same method . I have got some thymol .

[@bullwinklethemooseME]

thanks man

[@GattedGazoo91]

My high school chemistry teacher says it's a hell of a laxative.

[@KaidoLP]

In German the word Phenolphthalein hast a T plosiv in the middle, ist so weird to hear it without

[@zanpekosak2383]

What is the purpose of h2so4? Does it need to be conc.?

[@noahreckhorn6399]

It acts as a catalyst, and usually it needs to be conc.

[@GameDevCaptainBlack]

Sulphuric acid gets proton to acyl oxygen in ftalic anyhidride, its acyl carbon get ready to reaction, at the same time it gets activate phenol ring to attack. Rich phenol ring electrons (-) are warned by (+) protons of acid.

[@atishshahu540]

What is the procedure to make capb??

[@ChemExLK]

I reapeated the reaction you have done but with carbolic acid insted of phenol crystal. However in the end, after the phenolphthalein solution was added the precipitate was forms is ash color not white. After few minutes some sticky black colour oil like paste was occurred. So I couldn't take a precipitate to filter. But when I add NaOH to sticky black paste it turns red same as the phenolphthalein. Why is that ? Can you give me an explanation ?

[@thorium9190]

I rather make red cabbage indicator. Since I do not have these chemicals

[@nerdtopiaball5255]

Can you make a video how to make tashiro Indikator

[@sushant2664]

Phenolphthalein is used to indicate pH of other solutions. But, what is the pH of phenolphthalein itself?

[@AnitaSharma-tg4ws]

Hey Red! Can you please tell me why DCM was added?

[@Chemi4001]

For me it takes less than 30 min. for the phenol + phthalic anhydride + sulfuric acid to becomes dark red. p.s. I use molten phenol Edit 1: I keep heat it until minute 30 was reached and it becomes dark crimson (almost black but still contains crimson shade to it).

[@Prchemist06]

Can we use acetone or ethyl acetate

[@GameDevCaptainBlack]

Aceton mixes with water.. all phases mix each other. It is not good. DCM, CCl3 are useful and have lower boiling point for reversible on distillation.

[@Prchemist06]

@@GameDevCaptainBlack yeah I also that as well .But I inquired in case I dont get hold of Wood tarnish from which Nile used to extract DCM.

[@onesimpleclik]

that's really cool :)

[@jonardgopo7084]

Simplest method of 0.1% Phenolphthalein. Weigh 0.1g Phenolphthalein in a 100ml vol.flask and dilute/dissolve using 95% Ethanol. Fill up to mark.

[@Sahity]

it can measure acidic and alkaline ph?

[@ajja1458]

Is DCM the only option for the solvent? Could toluene or other solvent work? (In our school chlorinated solvents are strictly forbidden :(

[@anramba8371]

i am suffering from food in chemical poisoning it is very hard like metal and mercury

[@aloysiusdevadanderabercrombie8]

I got phenolphthalein in my school's science kit.

[@gorepuppy]

It used to be very common and used in laxatives. Someone poisoned me with it and damn near killed me with water loss from diarrhea. The way they poisoned me was still funny though. But I do not remember any safety info on the stuff back in the day. "here kids, play with a possible carcinogen that is also a very powerful laxative". I would be surprised if it is still in chemistry kits for children.

[@christianlien4249]

gorepuppy My school uses it on a regular basis. The sophomores I think are using it to test for unlabeled compounds

[@gorepuppy]

The little kits for young children had it. We were a mess back then. So you know that stuff led to some stories. Yep, I think I would prefer to use litmus paper but ya you can use it to learn a little bit about a liquid in a pinch. The coolest use for it though in my opinion is magic paint.

[@TheHeretic2011]

gorepuppy Be surprised. I bought a kids chemistry set for my daughter a year or so ago, and it has phenolphthalein in it.

[@joeuenos6700]

what is the type of your magnetic stirrer with hot plate do you use?

[@Bloated_Tony_Danza]

Not to be confused with phallic anhydride

[@عمربنالخطاب-ص8ف]

oooooh your synthetic its very cooool

[@gonzalo2010lab]

What does the reaction mixture has a red color ? can that be to the presence of a small amount phenol red that's produced by the sulfonation of some phenolphthalein ?

[@JayMark2049]

gonzalo2010lab I don't think so. Pretty sure it's due to the high acidity. But I could be wrong.

[@bradywells1293]

Phenolphthalein is always colorless is acidic solution. The reason the color change happens in phenolpthalein is apparently from a quinone group being formed from one of the phenol groups when it is deprotonated (only in basic solution). This qionone group is also formed in phenol red, giving it it's color too. I think it probably is from phenol red, because when he puts his product into the 2M HCl there's a yellow color produced.

[@juzeralirangwala3539]

Gr8 video

[@tirthv6746]

How to extract cellulose?

[@jaredgarden2455]

My first attempt at this looks like it failed :/ ive ended up with dark brown goo after filtration which i then put in the oven at 150*C to try and get the water out but now it looks like i burned it, fuck. Did you get a brown goo upon filtration then just put it under vacuum in a desiccator? Also upon addition to the HCl the precipitate that formed was pink not white like yours, Im not entirely sure what ive done wrong.

[@dakotagore9601]

I feel like I'm watching a meth diy

[@kenyu14689]

Is the blue liquid from washing a purple cabbage similar to this?

[@lassassindu5071]

Not the same molecule, but other pH indicators : anthocyanins.

[@juzeralirangwala3539]

I tried this method but don't know why failed to crystallise Phenolphthalein by hydrolysis. Any suggestions on how to get crystalline product ??

[@NileRed]

I had a really hard time recrystallizing the phenolphthalein, which is why I didn't show it in the video. So, unfortunately I don't have much advice

[@juzeralirangwala3539]

Nile Red No issues,i will try the whole procedure again and hope to get better results

[@АликАлик-ъ9м]

И что получилось?

[@bullwinklethemooseME]

no comments! wow

[@jacobdirecto277]

here because I'm bored and used this thing in a couple gen chem labs I forgot about

[@ludwigludwig3515]

Wonderful Chemistry.

[@Shaggyfauvorite]

PHENOLPHTALEINA

[@1337fraggzb00N]

Awesome. Now i can do things with stuff.

[@palakdubey6223]

It's too hard to pronounce phenolphthalein

[@tomasbrukstus9396]

what's that spinning thing inside?

[@Biteityeah]

+Tomas B It's a stir bar. It's being spun by the hot plate through magnetism.

[@cadellvandenheuvel949]

Why is sulfuric acid such a common catalyst?

[@smarphpharph5021]

Cadell Van Den Heuvel very strong acid, and 2moles of h+ per

[@cadellvandenheuvel949]

jake pole But why does that make it a good catalyst? What about a very acidic environment facilitates so many common reactions?

[@smarphpharph5021]

Usually, id say UTFSE, but... eh. Lol. H2SO4 in aqueous solutions will dissociate into 2H+. Those free acidic protons will protonate some portion of the structure being reacted with, which will destablize the structure, and ,"kick start" the reaction. As an example, with esters, tge carboxylic acids double bonded oxygen will pick up a free proton in acidic conditions, which essentially creates an imbalanced of electrons. As to why H2SO4 is used specifically, im not ENTIRELY sure, but id say its availability and the fact that less can be used compared to an acid like HCL, since you have 2 moles of H+ per mole rather than one (stronger acid)

[@djkontol]

i have no idea what is going on, but i enjoy watching your videos allot

[@LauRa-re9un]

Cancer danger!!

[@SmokedHam444]

Is this cheaper than buying it?

[@smarphpharph5021]

MatthiasChristiaens certainly not

[@laquade1]

but its fun.

[@user-kl1on3nw7y]

What's the best way to produce a large amount of oxygen!!!!

[@larrytischler8769]

Plant a lot of grass. Grass makes more O2 quicker than trees.

[@Hailfire08]

Used as a laxative? So does your poop come out pink or clear?

[@larrytischler8769]

It was pulled off the market after decades by ole bummer.

[@boobiesandshit]

o mg - I've been pronouncing it phenol-fftha-leen my whole life and no one corrected me ;-;

[@dimitriskemerlis4983]

So, you made solid indicator? Because I have seen this indicator only in liquid phase.

[@rajeshshahi1000]

It is better to buy phenolphthalein online.

[@nickolascrousillat4265]

Hhhhmmm a laxative I might try and make this in science class and put it in a drink and say it can tell its Ph and that it's safe to drink

[@doomdeathxx]

nose pero esa fenolftaleina no me da confianza para realizar una titulacion xD xD xD

[@austinbevis4266]

Can you show how to make carbon monoxide in your garage?

[@nightmarechameleon7502]

austin bevis planning something?

[@Ghorda9]

just turn on the car engine and keep it running, don't forget to close the garage doors and windows to trap it.

[@paulherrmann6434]

Mhmmm Phenol ..delicious

[@longplays2420]

Can you make oxygen?

[@konradlab3479]

H2O3 and KMno4 or MnO2

[@longplays2420]

lol you ruined it all ps that is irrelevant, you make oxygen by burning KMnO4 which is: 2 KMnO4 -> K2MnO4 + MnO2 + O2 then you clean the K2MnO4 and MnO2 to get O2 ez

[@DenyCreep]

mostest bestest

[@zeke2315]

epic gamer

[@gogear131]

well i actually failed chemistry.....twice..

[@robertkat]

I drink that with Scotch, nice flavour.

[@londifonerr9688]

Шавоооо

[@Joemamashouse69]

Nilered, "Pholphthalein is an extremely useful... Laxative." 🤣

[@silversagebrush]

im pretty sure my biology teacher used this chemical to show us something! I ended up having my teacher waft ammonia into my face and my nose burnt super bad (i didnt smell it directly)

[@alexi3489]

Hi! First of all, your videos are fantastic. I've always loved chemistry, and your videos are like an embodiment of that love. I was wondering why you used such small amounts of reactants, and more specifically, I want to know if I can scale it up, say 100 grams of phenol and 75 grams of phthalic anhydride. I know I would never use that much phenolphthalein, but I figure it couldn't be that hard to sell online. ;)

[@psychpile]

two grams of phenol, two grams of thaline.

[@Enjoymentboy]

I'm really enjoying going through the whole series of videos you've made and think an interesting addition to this one would be how to use it to test the concentration of various acids (ie hardware store grade sulfuric, HCL etc).

[@RaExpIn]

Nice Synthesis! I really like the triphenyl methane dyes :)

[@dvwebro]

Hey Nile. I would like to see a video with synthesis of other indicators, that have a similar structure. Phenolsulfonphthalein (Phenol red) and then maybe tetrabromophenolsulfonphthalein (Bromophenol blue).

[@mr.porridge4898]

Hi NileRed, I've been watching you videos lately to help me focusing on my studies (which are totally different from the arguments of your videos lol). they really helped me and they taught me loads of thing. I got a request for you, even if I know already the answer: Could you do a video about Thallium? I read about it in a book written by Agatha Christie, which used to work in a dispensary during first and second world war. Could you think about it? Thank you and thanks again for your great job!

[@gjollar412]

Welcome back to another episode of: “Why the fuck is this in my recommendations?”

[@kensclark]

I swear you were holding back a laugh when you said "phthalic anhydride" hahaha.

[@michaelhayward7790]

Why does it say illegal to sell separately on most ph indicator bottles?

[@mihneasimionescu2022]

+nilered can i also use chloroform instead of DCM?