32 g vanillin (bought in a grocery store) were rextyllised from hot water filtered and pressed dry. About 30g of slightly moist vanillin was obtained. The mp wasn't tested but it showed all proper signs of melting in hot water, forming a clear bottom layer.
Then a procedure identical to that performed by Uemura in Post 297806 (https://www.thevespiary.org/talk/index.php?topic=9683.msg29780600#msg29780600)
(uemura: "How to prepare hydroxyvanillin", Methods Discourse) was carried out, xcept on a 1/2 scale and at 15 C (instead of 20 C). H2O2 was old, so to make sure all KBr reacted, an additional <10mls was added. Some real tiny bubbles began to appear, so probably H2O2 wasn't bad.
The mixtr turned yellow-brownish during the addition, but NO Br-vanillin precipitation was apparent at any time.
The rxn was flooded w/icewater and the tiny crop of xtals was filtered, dryed and found to weigh ~4g. They don't melt at 100 C (good sign).
Merde :( .
Any ideas? Experiences? Help! :(
Antoncho
SWIM just took a look at some kitchen vanillin, and it indeed mentions sugar as cutting ingredient. SWIM thinks you might have brominated/iodinated some of your sugar. You might want to try some colour test for sugar identification. There are some simple test at http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA5/MAIN/WORDS/WORDS01.HTM (http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA5/MAIN/WORDS/WORDS01.HTM)
- but be carefull with your interpretation! Some of the test are based on the presence of aldehyde groups in sugars, and your vanillin has an aldehyde group as well.
You say "there was lots of tar"... did you use H2SO4? If you did, SWIM is almost sure the tar is "carbonized" sugar. Sulfuric acid decomposes sugar and leaves some weird stinking shit.
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