I've read that taurine can be synthesized and given to cats, so that they may follow a vegan diet.
I was wondering if anyone could please describe in detail how this is done in practice, describing the whole process of synthesis.
In 1993, about 5,000–6,000 tonnes of taurine were produced for commercial purposes: 50% for pet food and 50% in pharmaceutical applications. As of 2010, China alone has more than 40 manufacturers of taurine. Most of these enterprises employ the ethanolamine method to produce a total annual production of about 3,000 tonnes.
In the laboratory, taurine can be produced by alkylation of ammonia with bromoethanesulfonate salts."
So the precursor would likely be ethanolamine, which can be found virtually in every organism which possesses cells (you will see that if you follow the link to "ethanolamine").
From this precursor it seems to me that it would consist in mixing chemicals in a lab under the proper conditions. The process is described along with the commercial suppliers for the reagents in the paper that you can download here
Then it is a question of where the ethanolamine would come from.
If I go on the website of the supplier (Sigma-Aldrich)
... you can also see on the datasheet of the product that it has been heavily tested on animals, like any other chemical you can buy I suppose.