Hi,
I've been working on JP10-265428. The full literal translation isn't done yet,
but I thought I would post a quick paraphrasing of the patent since it might be
of interest and I may not get around to actually finishing the whole translation
anytime soon (since I am a lazy, lazy bastard and my job at the Ministry of
Truth eats up most of my time).
The actual mechanics of the process in the patent are pretty straightforward
and at the same time quite vague. Cold 3-alkoxy-4-hydroxybenzaldehyde is added
to cold non-halide acid, the mix warmed up and allowed to react, then some
water dumped in. They give a wide range of reactants, quantities, and
temperatures however. There are three concrete examples at the end.
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Publication date: 1998-10-06
Inventor(s): HARADA KATSUMASA;; SHIRAI MASASHI;; FURUYA TOSHIO
Applicant(s): UBE IND LTD
Requested Patent: JP10265428
Application Number: JP19970072239 19970325
IPC Classification: C07C47/565; C07C45/64
First comes the abstract; the patent is for an industrially suitable method
of producing protocatechualdehyde in high yield by dealkylation of
3-alkoxy-4-hydroxybenzaldehydes in the presence of a non-halide acid. The
alkoxy radical of the 3-alkoxy-4-hydroxybenzaldehyde here *must* have at least
two carbon atoms.
Next it describes the scope of the patent application and lists the patent
application clauses. These are under the headings marked "[blah blah 1]"
through "[blah blah 5]".
After this comes the detailed explanation of the patent, under numeric
headings 0001 to 0017.
0001: A description of the field under which this invention falls.
0002-0005: Descriptions of older techniques for producing
protocatechualdehyde and why they suck. Vanillin/AlCl3 method (J. Org. Chem.,
27, 2037(1962)) is the chief reference, with further mention of vanillin
processes involving HCl, HBr and acetic acid, and PCl5.
0006-0008: The patent starts listing example categories of suitable
3-alkoxy-4-hydroxybenzaldehydes. 0008 gives some specific examples that are
definitely suitable: 3-ethoxy-4-hydroxybenzaldehyde,
3-n-propoxy-4-hydroxybenzaldehyde, 3-isopropoxy-4-hydroxybenzaldehyde,
3-n-butoxy-4-hydroxybenzaldehyde, 3-isobutoxy-4-hydroxybenzaldehyde,
3-sec-butoxy-4-hydroxybenzaldehyde, 3-tert-butoxy-4-hydroxybenzaldehyde, "etc.".
0009-0011: Examples of suitable non-halide acids are given: sufuric acid,
pyrosulfuric acid (disulfuric acid), non-halide sulfonic acids, methane sulfonic
acid, ethane sulfonic acid, ethane disulfonic acid, benzene sulfonic acid,
benzene disulfonic acid, toluene sulfonic acid, napthalene sulfonic acid,
napthalene disulfonic acid.
Some guidelines to the process are given in these sections as well.
For every mole of 3-alkoxy-4-hydroxybenzaldehyde, 5-20 moles of acid are
required, with 5-10 moles being desirable. The acid should be 70-100% pure
by weight, with 85-100% being desirable. The reaction temperature should be
25-100 degrees C, with 25-70 degrees C being desirable. The initial
temperature should be 0-70 degrees C, with 0-40 degrees being desirable. The
amount of water added should be 0.5-10 liters per mole of 3-a-4-hb, with
0.5-5 liters being desirable.
0012-0016: "Examples of Execution" where they actually give details on
some tiny runs. These I present fully:
0013 Example of Execution 1
Inside an Argon gas stream, at room temperature, 96% by weight sulfuric acid
(60.20mmol) was placed into a 25ml flask; after reducing the temperature
to 5 degrees C, this temperature of 3-ethoxy-4-hydroxybenzaldehyde
(6.02mmol) was added, all the while stirring. Next, the temperature was
raised to 65-70 degrees C; after an additional 2 hours of stirring heated at
the same temperature, the reaction liquid was cooled to room temperature.
Then, to the thus obtained reaction liquid was added, with stirring, ice
water (20ml) and the reaction liquid stirred for 1 hour. After, when the
aqueous solution was analyzed by high speed liquid chromatography, it was
established that the conversion ratio of 3-ethoxy-4-hydroxybenzaldehyde was
97%, yield of protocatechualdehyde was 91%. Also, the entire procedure
described above was done under normal pressure.
0014 Example of Execution 2
Same, except the amount of 96% by weight sulfuric acid was changed to
116.19mmol, and the reaction time was changed to 1 hour. Procedure was
performed in the same manner as Example of Execution 1. The result was
conversion ratio of 3-ethoxy-4-hydroxybenzaldehyde 99%, yield of
protocatechualdehyde 96%.
0015 Example of Execution 3
Same, except the amount of 96% by weight sulfuric acid was changed to
30.15mmol, and the reaction time was changed to 11 hours. Procedure was
performed in the same manner as Example of Execution 1. The result was
conversion ratio of 3-ethoxy-4-hydroxybenzaldehyde 91%, yield of
protocatechualdehyde 84%. Results of the Examples of Execution are shown
in Table 1.
0016
[Table 1]
+----------------------+---------------+---------------+---------------------+
|Example of Execution | Sulfuric Acid | Reaction Time | Protocatechualdehyde|
| | mmol | hr | yield % |
+----------------------+---------------+---------------+---------------------+
|Example of Execution 1| 60.20 | 2 | 91 |
+----------------------+---------------+---------------+---------------------+
|Example of Execution 2| 116.19 | 1 | 96 |
+----------------------+---------------+---------------+---------------------+
|Example of Execution 3| 30.15 | 11 | 84 |
+----------------------+---------------+---------------+---------------------+
0017: A summary.
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DISCLAIMER: Myne japsaneses aint perfikt super number one, doubleplusgood etc.
etc. blah blah blah (aforementioned).
Cheers.