My first suggestion is to remind people that they need to allow emails from you or your confirmation may end up in spam. So, you should remind people to check spam for confirmation email.
So far, I do like the use of CAS numbers for searching for chemicals across the vendors. What will make your service better than most is if the data is up to date and those vendors really do supply the requested materials.
Thanks Joseph, we will add a notification about not marking our emails as spam.
The data is current and lists how long ago it was collected on the site. We haven't had any reported issues of vendors not supplying products, but that could certainly happen.