OrganoLeptic - 2017-08-13
Today I'll show you how to make benzyl chloride. This synthesis was loads of fun. I especially liked crying due to low-level exposure to the product during the filtrations. I hope I'll get the chance to use this product in one of my planned synthesis. If all goes well it will be quite a bitter experience :) Synthesis of benzyl chloride by nucleophilic substitution: - https://www.youtube.com/watch?v=lWFTYQ-x-SM by NileRed (benzyl alcohol + hydrochloric acid) - https://www.youtube.com/watch?v=1VIcoUKYHt8 by ChemPlayer (benzyl alcohol + hydrochloric acid + anhydrous zinc chloride) - https://www.youtube.com/watch?v=mtl-Hs66Uzo by chemx01 (benzyl alcohol + hydrochloric acid) Gas-phase free-radical chlorination of para-chlorotoluene to produce para-chlorobenzyl chloride: - https://www.youtube.com/watch?v=4DQuv6LjB80 by NurdRage This procedure is based on the following Sciencemadness thread: -https://www.sciencemadness.org/whisper/viewthread.php?tid=14063 comments by user Nicodem were especially useful If you would like to help me make videos you can do that by supporting me via Patreon: https://www.patreon.com/OrganoLeptic or you can donate using BitCoin: 1KUWpx4bVdWyrNSfNaWxfJD6jiyiyGPiLy WARNING: This video is only for entertainment purposes. If you rely on the information portrayed in this video, you assume the responsibility for the results. Have fun, but always think ahead, and remember that every project you try is at YOUR OWN RISK.
Hello, did you manage to gauge the purity of your final product? Did you try out the isopropanol/toluene azeotrope idea suggested by Melgar? (I know, I know...almost 3 yrs ago.)
Hello all. I know this post is 3 years old. Anyway, I´d like to point out that the glass flask is a borosilicate glas. It cuts the UV light almost 90%. If you do the same reaction in a quartz glass flask the yields are a lot better.
Doesn't the temperature spike suggest that whatever UV comes through is enough? You only need it for initiation anyway.
There is one chain termination missing, and that is where 2 benzyl radicals form 1,2-diphenylethane.
Nice video and explanation. I was thinking to do the experiment with toluene + Ca(ClO)₂ instead of TCCA, the TCCA in my country also contains Al2(SO4)3. Do yo think it would work with toluene + Ca(ClO)₂ and UV?
No it doesn't. You can use the TCCA with aluminium salt due to its insolubility in toluene. Also it is better to use the fresh toluene each time and distill it with a 200 mm column to obtain higher yield of benzyl chloride
will using a UV lamp be beneficial? or is bright sunlight needed instead? either way, nice job. i congratulate you on using a mortar and pestle to grind up TCCA- it is nasty enough in a block let alone a powder.
The reaction is initiated by chlorine radicals. These form in a process known as initiation in which UV light excites the bond causing the chlorine atom to vibrate enough split from the nitrogen. Then, in a process known as chain propagation, these chlorine radicals attack the hydrogen in the methyl group forming hydrogen chloride and a benzyl radical. This benzyl radical will then go on to attack a number of things, but most of the time, this will be another chlorine radical (chain termination) or the Cl-N bond of the trichloroisocyanuric acid (chain propagation). To answer your question there is nothing special about the sun. *We must add UV energy in order to excite the Cl-N bond*, but you need to be very careful. This reaction is quite exothermic, and when NurdRage did it in the gas phase, he experienced a problem with chlorine fires. I worry that using a UV lamp will cause the reaction to get to hot and perhaps go into *thermal runaway*. I personally would not recommend a UV lamp, although it may work if you have adequate temperature control (aka an ice bath).
@William AckersonDo you think an UV fluorescent tube would work? There are many frequencies in the UV range but unlike sunlight, I am worried whether the lamp provides just the right frequency for the chlorine to resonate.
The intensity can be easily regulated by placing the light source further (inverse square law) or using UV filter.
The ice bath is a good idea especially if the reaction rate is high enough even in cold.
@Libor Tinka you are definitely right about the unknown with the frequency. However since frequency and wavelength are inversely proportional, there must be some way to predict the ideal way to predict the ideal frequency to excite the chlorine enough to initiate. For example, microwaves used in consumer ovens produce waves with about 11-12cm wavelength. This is sufficient to add energy to the water molecules. I'll update you if I find any information about the ideal frequency range to split the chlorine, although it shouldn't take much convincing considering chlorine isn't too picky! ;)
You could use anhydrous lithium bromide as a catalyst to catalyze the uv light initiated chlorination of toluene to benzyl chloride.
http://www.sciencemadness.org/talk/viewthread.php?tid=14063
Even without a catalyst the initiation of the reaction was quick in the strong sunlight. (+ I had no bromide salts at the time.)
good to see new people joining this community
Chemistry always puts a smile on my face!
Can NaDCCA (sodium dichloroisocyanuric acid) be used instead of TCCA?
Can chlorine gas be pumped into the reaction flask directly and how to know it's enough?
interesting route, I will try it someday. thanks
I found this video in my recommended today, probably because I watch a lot of NileRed and Extractions & ire videos. By the way, you have a new sub.
For starting can add some polymerisation starter for styrol resin. Then need no light.
Very good job Organoleptic. I agree with you the yield could be better if you rinse the cianuric acid cake with toluene every filtration and do a fractional destilation. May be the idea of isopropanol/toluene azeotrope, Melgar said, works too. Azeotrope boiling point is 80,6ºC with 42% isopropanol/58% toluene. This way I think you could increase the amount of the fraction that distills above 173ºC.
Thank you! If I repeat this procedure I will try out the azeotrope.
@OrganoLeptic I think benzyl chloride should react with benzyl chloride and contaminate it. Just use a good fractionating column
can we make a LOHC by this?
I'll literally do this reaction to make benzyl alcohol
During the distillation of fractions - it is necessary to use a dephlegmator to increase the yield of the final product and increase its purity.
Can you use a short reflux condenser as a dephlegmator? Or how would you incorporate this in a standard glassware setup?
@Libor Tinka "Deflegmator" is Russian name for the Vigreux column or something like. An empty condenser can be used, but the separation will not be so good
Nice!
You can try to add slowly all TCCA to boiling toluene and heat it one hour like at patent US1280612 with toluene and dry calcium hypochloride.
Instead of hypochloride can add only radical initiater like for polyester used.
Excuse me, i can't understand why you wash the reaction mixture with water, i mean, doesn't Benzyl Chloride react with it to give Benzaldehyde?
And, about the usage of solar light as source of UV, is it enought strong? Isn't it blocked by the glass?
Thank you for this video anyway, and my congratulations for the reaction.
(Please, forgive me for my low level of English, but i'm not a native speaker)
Hey, I think you mixed up Benzyl Chloride and Benzal Chloride ;)
Benzal Chloride(the dichlorinated Form) will react with water to form benzaldehyde, as you said. Anyway benzyl Chloride also reacts with water, but it forms benzyl Alkohol. Thats also the reason why it is lacrymatory - in your eyes it forms benzyl Alkohol and hcl with the moisture in your eyes.
Hydrolysis of benzyl chloride is very slow at neutral conditions, thats why you can wash it with water without Problems.
I Hope I was able to help with your questions :)
Regular glass doesn't block uv. It's not sunglasses or safety glasses
Why did you run your fresh distillate through the filter?
some people take major joy in folding up filter papers, some others have it as a whole hobby to fold little animals out of paper
Where I can bay many glass bottles ?)
Bist du zufällig deutsch?
Nein, ich komme aus Slowenien.
Hättest du vlt. Interesse einer deutschen Chemie Whatsappgruppe beizutreten?
Danke für die Einladung. Aber ich habe keine Zeit und spreche kein Deutsch. Für diese Konversation verwende ich Google translate :)
cannagorilla - 2017-10-25
Your great! New subscriber here! Thank you for this synthesis I have only found the substitution reaction but I have no benzyl OH but lots of toluene.
OrganoLeptic - 2017-11-03
Thank you! I am glad to be of assistance.