What is the difference between a red CD and a blue CD?

As far as I know, there is no burning CD with red dye layer.

Out of curiosity, I helped you search online. I found this red CD you mentioned. Look at the information:

Blu-ray disc, aquamarine disc and deep blue disc all refer to the discs with metallized azo dyes. Because azo dyes are blue when combined with the silver reflective layer of optical disks, they are called Blu-ray disks. Blu-ray disc is stable and reliable in quality, and performs well in music CD burning. Besides these discs, there are some discs in red, black and purple on the market. These discs are colored by adding some dyes to the reflective layer, but their dye layers are still those three layers.

You got it? In other words, red is an extra dye, which has no practical effect, just looks good. Ha ha.