The present invention relates to novel yellow anionic dyes, a process for their preparation, certain novel intermediates necessary for their preparation and the use of these dyes for dyeing natural or synthetic materials, in particular, paper. The dyes are of formula (14), (15) or (16)

in which

• R₁ represents hydrogen, C₁-C₄alkyl, C₁-C₄alkoxy or SO₃H,
• R_{2 ...
  ]]> 8101731 http://www.patentstorm.us/patents/8101730/description.html}
• Patent Number:  8101730
• Publication Date:  2012-01-24
• Inventor:  Kuboshima, Yoshinori

Provided is a method for synthesizing a rare-earth oxo isopropoxide safely with a high yield, using a rare-earth metal, which is more inexpensive than anhydrous rare-earth chlorides, as a raw material.

In a solvent containing 90% or more by weight of isopropyl alcohol, a rare-earth metal and isopropyl alcohol are caused to react with each other in the presence of a mercury compound catalyst, a solvent is added thereto or the solvent is partially replaced, and then in a solvent ...
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