The Color of Ketone

[Bubbleplate]

I think I've discovered what causes different colors of Ketone.
The last few times I ran the MM Benzo Wacker, the Ketone came out water white. Aminated fine, but I was curious as to why it the color was so light.
Looking at all parameters, I realized that the NaOH I was using was old leftover stuff, which I had diluted down with distilled H2O to have enough to run the cleanup. A pH test gave an indication of about a 3-4% strength of NaOH.

I mixed up a fresh batch of NaOH, and strength was about 7-8%.
Ran MM Benzo and cleanup. During cleanup I could see during the NaOH wash that the oil had a Greenish-yellow tinge.
Sure enough, the Ketone that distilled off had that classic Greenish "antifreeze" color.
So.... I believe that the ultimate color of the Ketone comes from the strength of the NaOH wash, and how long one lets the oil sit with it in the sep funnel ( the longer the sep, the greener the Ketone).
BTW, I have stopped washing with saturated NaCl.
I do the bicarb wash 3 times, then 3 times with NaOH, then 2 times with distilled H2O.

[nitrous351]

This is a question about the purities of different kinds of NaOH. I would assume the qualities would be ranked in this order: lab grade > food grade > drain cleaner. Is this correct?
On the labels of OTC chemicals, such as H**t and high power drain cleaner (sulfuric) it has a part that has numbers to describe what chems are in the product.
I always assumed these were CAS numbers for the chems (or something similar). Is this correct? If I pick up a product that only has one number, does that mean that it's fairly pure, or does it mean that it only has one major chemical ingredient?
For instance, I've heard some bees say that some drain cleaners have detergent in them... would these only have one number on the label?
I guess the best way to state my question is, does the manufacturer have to disclose EVERY ingredient in a product, even if it is a detergent or lube or color shelf-life indicator?

Bubble: why did you stop doing the NaCl washes? What kind of effect does it have on your yiels? Do you do a post-wash distillation for additional purity? If you do, what effect does not washing have on the distillation? Good observation either way! I think a bunch of bees will soon bee testing your theory! peace

[Bubbleplate]

either NF or USP grade. I like "Food Grade" because there are real limits as to amount of Lead, Arsenic, and other heavy metals that can be in it. Believe it or not, alot of "Lab Grade" chems allow 5x or 10x more heavy metals and other contaminants in their formulations. The only way to know what you're getting in any chemical is to read the manufacturers analysis listed in the catalog or request a certificate of analysis.
Getting back to the washes, I stopped doing the Salt Water wash for 2 reasons:
1) I always had nasty emulsions that took forever to separate and wasted product.
2) It just didn't seem to clean the ketone, judging from the light color of the wash. Eliminating the NaCl washes hasn't affected my yield, in fact it's gotten better. I consistently get 125 ml K from a full MM Wacker.

The 3 Bicarb washes suck up alot of crap, and the NaOH washes do even more! Especially that first NaOH wash.
I've also found that by doing 2 or 3 final washes with distilled H2O after the NaOH washes make for a cleaner distillation and less tarry crap in the flask.
One other thing I do: even though its a pain, I rinse my Sep funnel in running water after EVERY wash.

[OcoteaCymbarum]

Those damn NaCl washes...
They take forever, you have to sep like 20, 30 times to get all the dcm out!!!
Just a question about your PdCl2. Is is stored under argon? Or does it come in a plastic bag like mine. I ask because I wonder about the water contained in it. I would increase the weight of the catalyst. 2 grams wouldnt be 2 grams anymore. For a 125 ml yield, do you keep MM ratios?

[Bubbleplate]

You are kidding, right?

I use the cheapest but good grade PdCl2 I can find. Some is "chunky" and I don't even bother to grind it; some is "Mars Red" ultra-fine powder and guess what? They all work just fine! Again, I make sure the analysis says it's 99%+ pure. Never concerned myself with the H2O content...
Truth be told, I usually throw in 2.5 grams instead of 2.0.
Just to be sure; catalysts are cheap compared to the final product!
I use the MM formula just as is. Get 125 ml every time as long as starting oil is 95%+ safrole ( home made or store bought).

[OcoteaCymbarum]

I wasnt kidding when i was talking about Palladium being stored under argon, I've seen it before supplied that way.

Anyway, after your post, I ran a Benzo Wacker with 150 g benzo and 190g safrole and 2.5 g PdCl2.

I prestirred the catalyst for about 4-5 hours then added the benzo. Then my plans changed so i had to leave everything to stir overnight.

Added the safrole over a period of 1 hour and 40 minutes dropwise. The temp went up to 60-64 and was kept there. My addition first started slowly then i gradually increased the drip rate. Left stirring for 6 hours at 60-64.
Edit: Hydrolysed the ketal with 1.7L 10% HCl
Then I did like you advised. 3 X bicarb, 3 X 5%NaOH(fresh) and twice with water. The water washes produced a similar effect to those NaCl only easier to work around. Pooled my two water washes to get the last DCM out.

First did a quick distillation and collected everything that came between 80(when safrole usually comes over) and 120.
Double distilled carefully. The safrole forerun was about 1-2 ml so it was kept in.
Beautiful clean ketone that has yet to go through amination to confirm its quality.

Yield: 154g!! My best ever!

Now, I'm not sure if its only skipping the NaCl washes that caused my increasy in yield(last time was a mere 96 g!).

I'm sure that extra .5 g of PdCl2 has had an effect. Prices for Palladium have gone down lately so its all good.

What I really wonder about is the addition rate and temperature of the reaction. Maybe adding safrole over a longer period results in higher yields. I remember reading a post lately about someone getting a great yield because is addition funnel had clogged up. Anybody?

So the conclusion is I think: Skip those NaCl washes. They take time and make you loose valuable product.

A 73-74% yield(molar) isnt bad after all!

[Bubbleplate]

Adding more PdCl2 ups the yield as I've found. Like I said, catalyst is cheaper than Ketone!

You added the Safrole - SLOWLY. I've been doing the same lately - adding it over 1 1/2 to 2 hours and always keeping the temp just at methanol boiling point or under. I feel this greatly helps the yields and keeps side-reactions down to a minimum.

I've found that skipping the NaCl washes helps yield since nothing is lost to nasty emulsions!

Finally, washing with distilled H2O after the NaOH washes ensures that no residual NaOH is in the Ketone to affect it when it's heated under distillation.

Good work!

[NeoSynthesis]

Just curious... ever tried scaling up mm's waker? seems to me that everyone's been fiddling with in in one way or another (adding catalyst, etc..) so i'm curious if anyone's ever tried upping the scale altogether. If so, any suggestions on what might be the best way to work that out? thanks ppls!

[OcoteaCymbarum]

I will report after, maybe in a week.

I will double everything, maybe a bit less benzo(dont need 50 extra grams for nothing) and 5g PdCl2. I will drip in my safrole over a 2 1/2 hours maybe 3 and see what it does.
I found that keeping the temp at 60-64 and not washing with NaCl saturated to greatly enhance my yields, so I guess I will hope for 250-300 grams of double distilled Ketone!

[Bubbleplate]

I don't think I'd want to be washing the product in anything bigger than a 4 liter Sep funnel!  I guess one could split up the post Wacker washes, but besides, if I'm getting 120-130 grams of Ketone, how much can you aminate at once, especially if one uses Nitromethane.
Scaling up a MM Wacker should be straight forward: just get a bigger flask and drip away....

[Bubbleplate]

As you scale it up, you really don't need all that extra Benzo. Also, I've found that one doesn't want to run the temp too low - seems like alot of Benzo precipitates out if you run it too cold, especially with added PdCl2.
60-64 is perfect.

[NeoSynthesis]

I've become something of a Hive regular lately    and can't begin to tell you how much I appreciate the incredible resources available here, and the help offered by all around good folk.

I've got a couple of questions that are probably best for the newbie forums but I figured since I ended up here, that perhaps other newbies will as well, and might also find this info helpful so here goes:

1. Wacker: What's the ideal length of a reflux column for this type of reaction? I've got a 400mm, would that work? What are the drawbacks/advantages to varried lengths available?

2. It is said that a 2-neck RBF should be used. How about a simple RBF with a Claisen adapter? In which case which of the two necks should have the reflux column & which should have the addtion funnel? (I'm guessing the one directly overhead for the addition funnel - figured i'd ask to make sure)

3. In distillation of Nitromethane from rc fuel - I've just about shit my pants from all I've read about it. Could someone who has done this please comment on what to expect and any related safety issues? Better yet, if someone could write up (or point to) a detailed procedure of how to go about this step t'would be really appreciated.

4. Finally, as far as vacuum sources go - I've seen a couple of "air condition" type pumps, putting out around 27-29" of vacuum. Can these be used for a reliable vacuum source? (seeing as the pump would have to run for quite a few hours at a time) What are some low-budget (but not totally bankrupt) alternatives?

Thanks in advance for all the help, will be glad to pass the knowledge & experience down the grape vine!

Bzzzzzzz

[Propoxyfiend]

No, No let me, ok?

1. Wacker: What's the ideal length of a reflux column for this type of reaction? I've got a 400mm, would that work? What are the drawbacks/advantages to varried lengths available?

2. It is said that a 2-neck RBF should be used. How about a simple RBF with a Claisen adapter? In which case which of the two necks should have the reflux column & which should have the addtion funnel? (I'm guessing the one directly overhead for the addition funnel - figured i'd ask to make sure)

3. In distillation of Nitromethane from rc fuel - I've just about shit my pants from all I've read about it. Could someone who has done this please comment on what to expect and any related safety issues? Better yet, if someone could write up (or point to) a detailed procedure of how to go about this step t'would be really appreciated.

4. Finally, as far as vacuum sources go - I've seen a couple of "air condition" type pumps, putting out around 27-29" of vacuum. Can these be used for a reliable vacuum source? (seeing as the pump would have to run for quite a few hours at a time) What are some low-budget (but not totally bankrupt) alternatives?

USE THE FUCKING SEARCH ENGINE.

possibee one day I will get a cool UTFSE icon like other members have displayed.  However, as of today I am not that cool.

[OcoteaCymbarum]

I will help you as much as I can
1. Wacker: What's the ideal length of a reflux column for this type of reaction? I've got a 400mm, would that work? What are the drawbacks/advantages to varried lengths available?

For a benzo wacker, any type of column would work. That is because you dont want to run it at a huge reflux, just very low. Of course if you need to buy a condenser, get it as long as you can, its always useful for refluxing. Anyway if you proceed to try MM nitromethane write-up, you will need a 600 mm length condenser because it refluxes so hard. Allinh type condensers are great for refluxing, Liebigs are for distillation. I found that running the wacker at around 60-65 is perfect which is just about the bp of the solvent, so it doesnt reflux hard, almost not at all.

2. It is said that a 2-neck RBF should be used. How about a simple RBF with a Claisen adapter? In which case which of the two necks should have the reflux column & which should have the addtion funnel? (I'm guessing the one directly overhead for the addition funnel - figured i'd ask to make sure)

No!!! You can use a Claisen instead of a 2 neck no problem but its the refluxing column that goes directly above your flask. The addition funnel is placed on the side adaptor.
I would suggest you get this book:
The organic Chem Lab survival Manual by Zubrick. Its essential for basic techniques, especially when your starting.

4. Finally, as far as vacuum sources go - I've seen a couple of "air condition" type pumps, putting out around 27-29" of vacuum. Can these be used for a reliable vacuum source? (seeing as the pump would have to run for quite a few hours at a time) What are some low-budget (but not totally bankrupt) alternatives?

You want a pump that pulls at least 27 inches, not anything below if you can. A lot of different pumps can be used, including a fridge compressor. HVAC pumps for air conditionning systems are great. Or just any vacuum pump make for labs and stuff. Your best bet would be an auction site, where u can find tons of pumps and you can make great bargains. My pump was bought of an auction site, cost me 50 bucks, pull about 29 inches. These pumps are made for continuous running and most have a thermal switch that turns the pump off if too hot. It's never happen to me, even after running the pump for 8 hours. The only drawback of such pumps: they can be real noisy


As for nitromethane, I cant help you, mine is 99.9% Nitro so I dont need distilling.

One last piece of advice. If you run MM benzo wacker, skip the saturated NaCL washes. Do 3 brine, 3 X 5% NaOH, then 2 water washes. Make sure you combine the water washes and put them back in the sep funnel to get some extrac DCM out.

Saturated NaCL is hard to separate from the DCM and you loose a lot of solvent and therefore product in the end.
Make sure you make the water washes after the NaOH. This is to make sure that you have no NaOh whatsoever left in the dcm. Other wise, you will loose some product that will polymerize when you try to distill it. I usually get about 125 grams of ketone that way. My last run afforded 154 grams so I can complain.

Hope this helped

[technology]

Hey Dude,

dont mind the flaming, all receive some of that.

here are some pumps well worth a look. cheap, just make sure you get a digital meter, cause you want to be accurate with your measure on what your rig pulls.

http://www.acsource.com/prod/yjvacpump.html

these are yellow jacket air con pumps, just the same as lab pumps but because they are sold as air con refrig pumps there cheeper..

OcoteaCymbarum, how nice of you   to help a fellow bee.

[wyndowlicker]

HEy now,


 Thats the best link for a cheap pump.He even gives you a free gallon of oil.What a guy.