"Transformation <diagram>".

Another guess is that it may mean something like "interaction <diagram>" or "influence", "effect" meaning the interaction between the elements or influence of the elements in the compound on each other - ”化：影響を他に及ぼすこと”（大辞泉）

See : http://www.google.co.th/search?hl=en&q="化1" 化学反応式　chemical r...

化1, 化2, etc. are mostly used in chemical patents or research papers. They indicate Chemical formulas 1,2 ... or Chemical reaction 1, 2 ...
化1, 化2, etc. are usually followed by formula of a chemical compound or some chemical reaction.

The word [化１] is a delimiter for inserting an image of a chemical formula, or a chemical reaction in the required format of a specification to be filed with the Japan Patent Office. If you want to insert an image of a numeircal formula, for example, you should provide a delmiter of [数１] (for the first numerical formula) in the previous line of the numerical formula to be inserted in the specificaiton in order to satisfy the formality requirement. That is, the word of interest is required to meet the formality requirement of the Japanese Patent Law.

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Note added at 2 days4 hrs (2011-04-18 22:33:17 GMT)
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You can translate such a delimiter into "Chemical Formula 1", or "Numerical Euation 1", etc. according to a following image.