Chloroplatinic acid, which was the first platinum catalyst used in organosilicon -- at least  I haven't seen anything earlier in the literature. Today is still in the silicone industry is not old. Chloroplatinic acid (isopropanol solution) was first discovered by John Speier of Dow Corning Company in the catalytic effect of hydrosilane addition (trichlorosilane, methyl dichlorosilane and olefin addition reaction), therefore, chloroplatinic acid is also called Speier catalyst. Out of respect for the discoverers, I will refer to the SPEIER catalysts below.
Speier catalyst, the simplest way of synthesis: chloroplatinic acid dissolved in isopropyl alcohol. And notice, I said synthetic, because isopropanol actually coordinates here, it's not just dissolved, but then there are other things, like tetrahydrofuran and so on.
Simple synthesis of chloroplatinic acid: platinum dissolved in aqua regia. Usually silicone industry people buy ready-made, in my experience, different sources, quality is different. However, in general, as long as the purity is high enough, can be used. Perhaps due to the inherent insufficiency of the Speier catalyst, Dow Corning's Willing David N(US3419593, 1968) and GE's Karstedt B (US3775452, 1973) further improved on this catalyst, That is, the substitution of ethylene tetramethyldisiloxane for isopropanol complexing agents results in catalysts that are more stable, more compatible with silicone polymers, and more efficient (in most cases).
In theory, Willing's invention patent was published earlier than Karstedt's, but from the two patents it is clear that Karstedt did more scientifically by pointing out the complex action of enyltetramethyldisiloxane and by using an alkaline substance (sodium carbonate) for the synthesis of this catalyst. In terms of theory and practice, Karstedt is better than Willing. It is not clear from the time of patent publication whether Karstedt was inspired by Willing. In the experiment, Willing reacted dienyl tetramethyldisiloxane with chloroplatinic acid at 120 ° C, while Karstedt reacted dienyl tetramethyldisiloxane with chloroplatinic acid (salt) at about 70 ° C, assisted by sodium carbonate. As far as I am concerned, the Willing method is prone to platinum black and has few products, while the Karstedt method has high yield, stable products and good operation reproducibility.
Thereafter, the dienyltetramethyldisiloxane platinum complex, known as the Karstedt catalyst, is presumably based on these factors, and may be commercial factors. There are also catalysts called Willing-Karstedt catalysts.