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name         Taing O.
age          50s

Question -   I just sent a question about PABA. In one of your
answers, you mentioned it was para-amino benzaldehyde. But in another
answer, you said it was para-amino benzoic acid. Whic is correct?
What I want to get information is the manufacturing method and uses of
para-amino benzaldehyde (not p-amino benzoic acid).
This question overwrites if PABA is p-amino benzoic acid.
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The sunscreen PABA is para-aminobenzoic acid.

Richard E. Barrans Jr., Ph.D.
Director of Academic Programs
PG Research Foundation, Darien, Illinois
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http://www.naturalhealthnotebook.com/Vitamins/PABA_P-amino-benzoic_acid.htm

PABA = P-amino-benzoic acid

IT IS NOT THE ALDEHYDE VERSION ( PARA - AMINO BENZALDEHYDE).

REGARDS,
DARIN WAGNER
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Dr. Taing:

PABA is para-aminobenzoic acid.

Regards,
ProfHoff 485
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Dr. Taing O.
  PABA is the acronym for p-amino benzoic acid. It is used as an
anti-bacterial agent, as a sun screen, and as a chemical intermediate in the
synthesis of other compounds. You can find out the details from citations in
the Merck Index. The compound p-amino benzaldehyde has the empirical
formula:
C7H7N1O1. This empirical formula is not attributed to p-amino benzaldehyde
in either the Handbook of Chemistry and Physics or Lange's Handbook of
Chemistry, so while it probably can be synthesized, it is not a common
chemical reagent. From its structure one would expect it to be very unstable
with respect to oxidation, either photochemically or contact with
atmospheric oxygen. In addition, aromatic aldehydes react with aromatic
amines to form a class of compounds called "aldimines" that have the
structure:
PHENYL -- CH = N -- PHENYL. Since p-amino benzaldehyde has both amine and
aldehyde functionality it is very likely that it will polymerize to form
"poly-aldimines". Interesting structures, but I have no idea about
properties etc. The next place to start to find out some information on it
would be the Baker or Sigma Aldrich chemical reagent catalogs.

Vince Calder
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