How is carbon disulfide used to make rayon?

In the production of viscose rayon, carbon disulfide is a critical reagent used to transform purified cellulose into a liquid state suitable for fiber formation.12

The process follows these essential steps:

• Alkali Treatment: Purified cellulose is first treated with caustic soda (sodium hydroxide) to create alkali cellulose.1
• Xanthation: Carbon disulfide is added to the alkali cellulose to form cellulose xanthate, which is then dissolved in sodium hydroxide to produce a syrupy, viscous solution known as viscose.123
• Extrusion and Regeneration: This viscose solution is forced through a spinnerette into a coagulating bath containing acids and salts. This bath reconverts the cellulose xanthate back into solid cellulose filaments while setting free the carbon disulfide.12

Because carbon disulfide is toxic and its release poses environmental concerns, modern manufacturing often faces strict regulations, leading to the development of alternative processes like lyocell.1