Soda ash substitute for reactive dyeing is a chemical substance used in the dyeing of cellulose fibers, such as cotton, using reactive dyes. It is an alternative to traditional soda ash, which is commonly used as a dye fixative but can have negative impacts on the environment.

The functions of soda ash substitute for reactive dyeing include:

1. Providing alkalinity: Soda ash substitute provides the necessary alkalinity for the reactive dye to react with the fiber, resulting in a permanent bond between the dye and the fabric.
2. Improving color yield: Soda ash substitute can enhance the color yield of the dye, resulting in more vibrant and intense colors.
3. Reducing environmental impact: Soda ash substitute is a more environmentally friendly alternative to traditional soda ash, as it does not produce as much wastewater or cause as much pollution.
4. Reducing energy consumption: Soda ash substitute can be used at lower temperatures than traditional soda ash, reducing the amount of energy required to heat the dye bath.
5. Reducing fiber damage: Soda ash substitute can also reduce the damage to the cellulose fibers caused by traditional soda ash, resulting in a softer, more flexible fabric.

Overall, the use of soda ash substitute for reactive dyeing is an important step towards sustainability in the textile industry, as it allows for high-quality coloration of cellulose fibers while reducing negative impacts on the environment and promoting energy efficiency.