Hello, everyone !
I am looking for information on the operation of a catalyst in complex form based on stannic oxide / catalysis composite
sulfuric acid allowing the condentation reaction to form allantoin.
I put so attached the original patent and translated into English.
Thanks for your help
best regards,
Thomas
Hello Thomas, many thanks for sharing this very interesting technical question with the RG community. When you take a closer look at this patent, you really wonder if the inventors / researchers knew what they were doing. I think that nobody knows what the composition of this "catalyst" is. It is quite a weird mixture and reminds me of alchemy. It's not surprising that the authors do not provide any formulas. In the end, the goal of this invention was the synthesis of allantoin from glyoxylic acid. This can be much easier achieved by the reaction of glyoxylic acid with urea as shown in the attached Scheme wich was taken from the German Wikipedia entry on "Allantoin". Thus you don't need to be ashamed when you have no idea what's going on in this catalyst preparation. I have no idea either! 😎
Good luck with yopur work and best wishes, Frank Edelmann
Hi Franck, thank you for your answer, I think SnO2 activates the electrophilia of the carbon of the acid, what do you think ?
Dear Thomas, thank you for your kind response and question. Yes, you are absolutely right. Tin dioxide itself is well known for being able to activate carbonyl groups. As a typical examle please see the following potentially useful RG link in which the use of mesoporous SnO2 is reported:
Superior performance of mesoporous tin oxide over nano and bulk in activation of carbonyl group: Conversion of bio-renewable feedstock
Article Superior performance of mesoporous tin oxide over nano and b...
There are quite a few other closely related articles about carbonyl activation by SnO2 in the chemical literature.
Moreover, the catalyst system "sulfated tin oxide" (STO) has been extensively studied. For more information about STO and its uses please have a look at the following very instructove review article:
Sulfated tin oxide (STO) – Structural properties and application in catalysis: A review
Article Sulfated Tin Oxide (STO)-Structural Properties & Application...
Fortunately this review article has also been posted by the authors as public full text on RG. Thus you can freely download it as pdf file. In the light of these studies the Chinese patent mentioned in your question doesn't look quite as confuse as I originally thought.
Good luck with your research and best wishes, Frank Edelmann