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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: masteroc on March 04, 2011, 12:09:49 AM

Title: Fused Glassware
Post by: masteroc on March 04, 2011, 12:09:49 AM: So far this year in Organic II, I have done a few labs where the lab manual and instructor have been very specific about some steps where a strong base has been used in a round bottom flask and thermometer adapter. They have said and have shown us that the glassware will fuse together. I asked my instructor, but she didn't know the answer as to why a strong base will fuse the two glass pieces. Anyone have an idea?

Thanks
Title: Re: Fused Glassware
Post by: discodermolide on March 04, 2011, 01:13:55 AM: Quote from: masteroc on March 04, 2011, 12:09:49 AM
So far this year in Organic II, I have done a few labs where the lab manual and instructor have been very specific about some steps where a strong base has been used in a round bottom flask and thermometer adapter. They have said and have shown us that the glassware will fuse together. I asked my instructor, but she didn't know the answer as to why a strong base will fuse the two glass pieces. Anyone have an idea?

Thanks

The strong base attacks the glass at the joint effectively acting like glue.
If you heat it with a heat gun and tap gently they should be able to be separated. Don't burn yourself.
Title: Re: Fused Glassware
Post by: masteroc on March 04, 2011, 01:17:23 AM: Thanks for the info, would you happen to know the name or type of reaction that occurs? I am very interested in finding out more about this, just because i'm curious.
Title: Re: Fused Glassware
Post by: Borek on March 04, 2011, 03:49:11 AM: Glass dissolves in strong bases (think sodium metasilicate), then recrystallizes; effect is especially prominent on the grounded surfaces where the surface in contact with solution is larger than in other places.
Title: Re: Fused Glassware
Post by: TSClimber on March 05, 2011, 05:15:21 AM: you can try and stop it happening my using silicone grease between the ground glass joints but strong base will also dissolve that if its refluxing!