Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: Garabato on 31/10/2008 04:09:54

Title: How is acetylene prepared from calcium carbide?
Post by: Garabato on 31/10/2008 04:09:54
Hello

If currently doing a research job concerning a process for the preparation of propionic acid from calcium carbide, and it turns out that one of the steps involved is the preparation of acetylene from calcium carbide. Wikipedia says, and pretty much every book seems to agree, that the main way to manufacture acetylene is to make the calcium carbide react with water; which is why I find it so odd that I have been unable to find an article on the subject. WIPO (http://www.wipo.int/pctdb/en/wo.jsp?WO=2007096271) has something about the preparation of acetylene, but they use a completely different method. I know is supposed to be a very old and well known reaction, but I can't find any articles describing it in detail. ¿Does anyone knows where can I find a modern study of this process??  [???]

Before someone suggest it, I know there is a nice article (http://www.enotes.com/how-products-encyclopedia/acetylene) about it in "how products are made". However, I don't like it for two reasons: (1) I'm looking for a much more technical approach, and (2) "How products are" web page as a reference fails to look serious in a scientific paper  [;)]

Anyway, if anyone has some info about it or knows where I can find it, it would be really appreciated.
Title: Re: How is acetylene prepared from calcium carbide?
Post by: Bored chemist on 31/10/2008 07:07:31
I doubt there's a paper anout it. It really is a matter of "just add water".
YOu might want to look up Kipp's aparatus or have a look here.
mattson.creighton.edu/Download_Folder/QuimicaArticleMGC-Oct2005.pdf
Title: Re: How is acetylene prepared from calcium carbide?
Post by: lightarrow on 31/10/2008 17:42:41
Quote from: Garabato on 31/10/2008 04:09:54
Hello

If currently doing a research job concerning a process for the preparation of propionic acid from calcium carbide, and it turns out that one of the steps involved is the preparation of acetylene from calcium carbide. Wikipedia says, and pretty much every book seems to agree, that the main way to manufacture acetylene is to make the calcium carbide react with water; which is why I find it so odd that I have been unable to find an article on the subject. WIPO (http://www.wipo.int/pctdb/en/wo.jsp?WO=2007096271) has something about the preparation of acetylene, but they use a completely different method. I know is supposed to be a very old and well known reaction, but I can't find any articles describing it in detail. ¿Does anyone knows where can I find a modern study of this process??  [???]

Before someone suggest it, I know there is a nice article (http://www.enotes.com/how-products-encyclopedia/acetylene) about it in "how products are made". However, I don't like it for two reasons: (1) I'm looking for a much more technical approach, and (2) "How products are" web page as a reference fails to look serious in a scientific paper  [;)]

Anyway, if anyone has some info about it or knows where I can find it, it would be really appreciated.
How would you do to prepare CO2 from vinegar and baking soda? The same...
I only would recommend you to store CaC2 in dry conditions, it reacts even with air's water vapour (you wouldn't like to have the lab's air saturated with C2H2!).
Title: Re: How is acetylene prepared from calcium carbide?
Post by: blakestyger on 31/10/2008 22:48:03
Old bicycle lamps were run on carbide, and I remember as a schoolboy it was possible to buy it at hardware stores - which we did, and then put it in a screw top Corona bottle with a bit of water to make a bomb.  Glass everywhere - we were lucky to make to adulthood.
Title: Re: How is acetylene prepared from calcium carbide?
Post by: Garabato on 01/11/2008 03:03:10
"I doubt there's a paper anout it. It really is a matter of "just add water"."

Yeah, I know. And that really sucks. Its not like papers are necessary to make the acetylene, but my teacher is really picky about having references from an important journal  [:-\]
Title: How is acetylene prepared from calcium carbide?
Post by: Chemistry4me on 20/11/2008 06:54:13
CaC2 + H2O > C2H2 + CaOH
Title: How is acetylene prepared from calcium carbide?
Post by: lightarrow on 20/11/2008 16:05:25
Quote from: Chemistry4me on 20/11/2008 06:54:13
CaC2 + H2O > C2H2 + CaOH
You haven't balanced it.
Title: How is acetylene prepared from calcium carbide?
Post by: Chemistry4me on 22/11/2008 00:43:06
Hmmm... I can't believe I didn't even know thw formula for calcium hydroxide. My mistake so it should be CaC2 + 2H20 > C2H2 + Ca(OH)2
Cheers lightarrow
Title: How is acetylene prepared from calcium carbide?
Post by: lightarrow on 22/11/2008 11:11:10
Quote from: Chemistry4me on 22/11/2008 00:43:06
Hmmm... I can't believe I didn't even know thw formula for calcium hydroxide. My mistake so it should be CaC2 + 2H20 > C2H2 + Ca(OH)2
Cheers lightarrow
To edit formulas it's very simple: you press the "preview" button and now you have a window with more options; for example with the buttons "sup" or "sub" you can write numbers (or letters) as apex or subscript, respectively (after having evidenced them), change colors, font, size, ecc. E.g. :

CaC2 + 2H20 → C2H2 + Ca(OH)2