Selectivity improvement in oxygen delignification and bleaching of lignocellulose pulp using singlet oxygen

A process for the delignification or bleaching of lignocellulosic pulp comprising the steps of:

• a) providing an aqueous or non-aqueous mixture of pulp under typical oxygen delignification conditions, b) separately providing a stream of molecular oxygen, reacting the molecular oxygen light in the presence of visible light and a chemical agent, photochemically converting a portion of the molecular oxygen to singlet oxygen, and c) subsequently contacting pulp or pulp mixture with the singlet oxygen stream.

The process of 8 wherein the singlet oxygen is added to one of more stages of an oxygen delignification process.

A process for the delignification or bleaching of lignocellulosic pulp comprising the steps of:

• a) providing an aqueous or non-aqueous mixture of mechanical pulp under typical mechanical pulping conditions, b) separately providing a stream of molecular oxygen, reacting the molecular oxygen in the presence of visible light and a chemical agent, photochemically converting a portion of the molecular oxygen to singlet oxygen and c) subsequently contacting pulp or pulp mixture with the singlet oxygen stream.

A method to generate singlet oxygen that comprises the steps of providing a molecular oxygen source, a visible light source, a chemical agent wherein the molecular oxygen source provides a stream of molecular oxygen into a chamber or a series of chambers containing the chemical agent, contacting the molecular oxygen with the chemical agent in the presence of visible light from the light source.