Benzoin : Organic synthesis - without using cyanide salt

[@jamesg1367]

Vitamin B1 versus cyanide. Tough choice. :-) Nice work!

[@runzsh]

The yield calculation which is leading to 23% yield is flawed. If we retrospect the calculation it leads to the theoretical yield being calculated around 41 grams. 20ml Benzaldehyde weights around 20 grams and only reactant that is consumed is Benzaldehyde(catalysts being regenerated), we always get similar amount of Benzoin, conservation of mass. I think you have mistaken the stoichiometry of the reaction, i.e Molar Ratio of Benzaldehyde : Benzoin :: 2 : 1. Molar Ratio 1:1 gives 23% yield. Correct calculation yields around 45% yield of Benzoin which is appreciable!!

[@kaezaklimber3391]

very good demonstration!! by the way, please take a quick look at the theory background because its believed that there is no carbene involved, but in fact an "thiazole ylide". just double check the structure of that carbon atom between the nitrogen and sulfur. It appears trivalent but the H atom is simply omissed as normally. Structurally it is tetravalent, as it is used to have a hydrogen or even a methyl group (whatever R group not to make it trivalent) bonded to it.

[@abhinabhdas7099]

Mind-blowing 🔥

[@sudipghorai3783]

Sir, (A)What is the difference between addition of a reagent " dropwise" and"one time"? (B)Why the book suggests us "to add the sodium hydroxide solution dropwise over a period of several times"? = Is the reaction, thiamine hydrochloride to thiamine is exothermic..?As thiamine a heat sensitive reagent, that's why it(sodium hydroxide solution)should be added over a several period of time with small installment..So, the less amount generated heat quickly absorb by the ice bath.. (C)Why thiamine is stable in acidic medium but not much stable in basic medium?

[@retireeelectronics2649]

Very nice crystals

[@mcreativenotes812]

We can used instead of thiamine vitamin B1

[@foc2241]

Verz nice mechanism😁

[@NandanaKrishna-qb7qw]

can we use any other alcohols?

[@sarkar506]

nice

[@danielasarmiento9282]

Nice video! Do you have a book or something where you get this method of synthesis from?

[@morlanius]

I think you could increase yield by dissolving the thiamine directly in the alcohol phase avoiding any need to add water. And if you pre-heat the funnel and flush some hot alcohol though it before you start the filtration it sometimes helps prevent a lot of crystallisation in the paper.

[@sudipghorai3783]

As thiamine hydrochloride is sparingly soluble in ethanol and highly soluble in water. So, we have to must use the water but as minimum as possible, because addition of more water should increases the polarity of the medium and it should decreases the dissolving rate of benzaldehyde into ethanol...And the idea of filtration while recrystallization is useful.

[@h0lx]

very cool!

[@JorgeStolfi]

Wikipedia says that benzoin has a "light camphor-like odor". Is it possible that the strong disagreeable odor you reported is due to traces of some sulfur-containing impurity derived from the thiamine?

[@sudipghorai3783]

Sir,is it is mandatory to dry the crude product completely, which i want to recrystallized?

[@vibzzlab]

No it's not absolutely necessary

[@sudipghorai3783]

Sir, lf I use little bit more water to dissolve thiamine hydrochloride (about 3.5 gm thiamine hydrochloride+20 ml water) is there any problem...

[@vibzzlab]

No problem

[@WIN4iG]

Hello, can you please tell me if I can use vanillin instead of benzaldehyde to do a similar reaction?

[@bromisovalum8417]

iirc it will not work when the benzaldehyde is substituted with a phenolic or amino group in ortho or para position. However a mixed benzoin condensation may still be possible, say vanillin and benzaldehyde (as benzaldehyde can both donate and accept proton). And using thiazolium salt/base catalyst the reaction can even be extended to aliphatic aldehydes, the Stetter reaction.

[@itheharshaik]

Hello sir please help me to make Sulfur mono bromide

[@Hukum7860]

Hello sir iam chemestry lecturer give me ur moble no