There is scant evidence that there is such a thing as a snake repellent, and Phenol is not it.
A decidedly western source from 1970s does not list Phenol as a supposed repellent, but decries the general lack of actual repellents.
A patent from 1999 mentions only one preexisting repellent ('Dr.T's'), containing Naphthalene and Sulfur as active ingredients. The patent itself proposes essential oils with a strong smell.
Papers are witten on the efficacy of the naphthalene and other smelly repellents, and are generally negative (small effect if any, restricted to specific species)
A fact sheet citing literature comes to the conclusion that there is no known repellent, althought the list does not explicitly contain Phenole
Several potential home remedies were evaluated to determine if they
would repel black rat snakes. Treatments tested included gourd vines,
moth balls, sulfur, cedar oil, a tacky bird repellent, lime, cayenne
pepper spray, sisal rope, coal tar and creosote, liquid smoke,
artificial skunk scent, and musk from a king snake (they eat other
snakes) (San Julian and Woodward 1985). None of these remedies
repelled black rat snakes.
A work finally recognizing some Asian influences (Japan...) also finds no clear repellent
A study from India with severe methodological problems finds some efficacy for some oils from plants (they were looking at the possible value of known home remedies), though they do not even mention any belief in Phenol.
Another study from India, this time with more problems than redeeming qualities discusses basil as an effective repellen, again no mention of Phenole
Actually, there is a wealth of papers from India investigating the snake repellent properties of one or the other plant, often coming to the conclusion that they do work fine, never explaining why snakes are still such a problem.
This Australian paper seems to look into the Phenol-belief (in terms of tracing it, not testing it), but it is access-restricted