Digestion accelerator and method for producing pulp using same

Abstract

A digestion accelerator includes a specified quaternary ammonium compound, and at least one amine compound selected from the group consisting of a specified primary monoamine, a specified secondary monoamine, and a specified tertiary monoamine. A mass ratio between the quaternary ammonium compound and the amine compound is 5:1 to 10000:1. A method for producing pulp includes a digestion step of adding at least one main agent selected from the group consisting of an alkaline main agent and a sulfite-based main agent, and a digestion accelerator, to digest a material including lignocellulose, in which the digestion accelerator is the above digestion accelerator.

1 . A digestion accelerator comprising:
 a quaternary ammonium compound represented by formula (1); and   at least one amine compound selected from the group consisting of a primary monoamine represented by formula (2), a secondary monoamine represented by formula (3), and a tertiary monoamine represented by formula (4),   
       
         
           
           
               
               
           
         
         wherein, in formula (1), 
         R 1  is an alkyl group having 8 to 22 carbon atoms, a hydroxyalkyl group having 8 to 22 carbon atoms, an alkenyl group having 8 to 22 carbon atoms, or a hydroxyalkenyl group having 8 to 22 carbon atoms, 
         R 2  is an alkyl group having 1 to 22 carbon atoms, a hydroxyalkyl group having 1 to 22 carbon atoms, an alkenyl group having 2 to 22 carbon atoms, a hydroxyalkenyl group having 2 to 22 carbon atoms, or an (A 1 O) n Y group, 
         R 3  and R 4  are each independently an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, a hydroxyalkenyl group having 2 to 4 carbon atoms, an aryl group, a benzyl group optionally having an alkyl group having 1 to 4 carbon atoms, a phenethyl group optionally having an alkyl group having 1 to 4 carbon atoms, a glycidyl group, or an (A 1 O) m Y group, 
         N represents a nitrogen atom, 
         X p−  represents a counterion, and is an inorganic anion or an organic anion, and p represents a valence of an ion, 
         A 1 O is an alkyleneoxy group having 2 to 4 carbon atoms, and Y is a hydrogen atom or an acyl group, and 
         n is an integer of 1 to 15 and m is an integer of 1 to 15; 
       
       
         
           
           
               
               
           
         
         in formula (2), R 5  is an alkyl group having 1 to 22 carbon atoms, an alkenyl group having 2 to 22 carbon atoms, a hydroxyalkyl group having 1 to 22 carbon atoms, a hydroxyalkenyl group having 2 to 22 carbon atoms, or an (A 2 O) k Z group, A 2 O is an alkyleneoxy group having 2 to 4 carbon atoms, Z is a hydrogen atom or an acyl group, and k is an integer of 1 to 6; 
       
       
         
           
           
               
               
           
         
         in formula (3), R 6  and R 7  are each independently an alkyl group having 1 to 22 carbon atoms, an alkenyl group having 2 to 22 carbon atoms, a hydroxyalkyl group having 1 to 22 carbon atoms, a hydroxyalkenyl group having 2 to 22 carbon atoms, or an (A 3 O) r Z group, A 3 O is an alkyleneoxy group having 2 to 4 carbon atoms, Z is a hydrogen atom or an acyl group, and r is an integer of 1 to 12; and 
       
       
         
           
           
               
               
           
         
         in formula (4), R 8  and R 9  are each independently an alkyl group having 1 to 22 carbon atoms, an alkenyl group having 2 to 22 carbon atoms, a hydroxyalkyl group having 1 to 22 carbon atoms, a hydroxyalkenyl group having 2 to 22 carbon atoms, or an (A 4 O) t Z group, A 4 O is an alkyleneoxy group having 2 to 4 carbon atoms, Z is a hydrogen atom or an acyl group, and t is an integer of 1 to 12, and 
         R 10  is an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, a hydroxyalkyl group having 1 to 4 carbon atoms, a hydroxyalkenyl group having 2 to 4 carbon atoms, or an (A 5 O) u Z group, A 5 O is an alkyleneoxy group having 2 to 4 carbon atoms, Z is a hydrogen atom or an acyl group, and u is an integer of 1 to 12. 
       
     
     
         2 . The digestion accelerator according to  claim 1 , wherein a mass ratio between the quaternary ammonium compound and the amine compound is 5:1 to 10000:1. 
     
     
         3 . A digestion accelerator comprising:
 a quaternary ammonium compound represented by formula (1); and   a sulfur-containing compound that generates a sulfide ion, a polysulfide ion, or a hydrogen sulfide ion in the presence of the quaternary ammonium compound,   
       
         
           
           
               
               
           
         
         wherein, in formula (1), 
         R 1  is an alkyl group having 8 to 22 carbon atoms, a hydroxyalkyl group having 8 to 22 carbon atoms, an alkenyl group having 8 to 22 carbon atoms, or a hydroxyalkenyl group having 8 to 22 carbon atoms, 
         R 2  is an alkyl group having 1 to 22 carbon atoms, a hydroxyalkyl group having 1 to 22 carbon atoms, an alkenyl group having 2 to 22 carbon atoms, a hydroxyalkenyl group having 2 to 22 carbon atoms, or an (A 1 O) n Y group, 
         R 3  and R 4  are each independently an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, a hydroxyalkenyl group having 2 to 4 carbon atoms, an aryl group, a benzyl group optionally having an alkyl group having 1 to 4 carbon atoms, a phenethyl group optionally having an alkyl group having 1 to 4 carbon atoms, a glycidyl group, or an (A 1 O) m Y group, 
         N represents a nitrogen atom, 
         X p−  represents a counterion, and is an inorganic anion or an organic anion, and p represents a valence of an ion, 
         A 1 O is an alkyleneoxy group having 2 to 4 carbon atoms, and Y is a hydrogen atom or an acyl group, and 
         n is an integer of 1 to 15 and m is an integer of 1 to 15. 
       
     
     
         4 . The digestion accelerator according to  claim 3 , wherein the sulfur-containing compound comprises at least one compound selected from the group consisting of thiosulfate, hydrogen thiosulfate, sulfite, hydrogen sulfite, disulfite, dithionite, dithionate, disulfate, peroxosulfate, peroxodisulfate, and polythionate. 
     
     
         5 . The digestion accelerator according to  claim 3 , wherein a mass ratio between the quaternary ammonium compound and the sulfur-containing compound is 1:2 to 100:1. 
     
     
         6 . A method for producing pulp, the method comprising a digestion step of adding at least one main agent selected from the group consisting of an alkaline main agent and a sulfite-based main agent, and a digestion accelerator, to digest a material including lignocellulose,
 wherein the digestion accelerator is the digestion accelerator according to  claim 1 .   
     
     
         7 . The method for producing pulp according to  claim 6 , wherein a content of the digestion accelerator is 0.001% by mass to 1.0% by mass relative to the material including the lignocellulose. 
     
     
         8 . The digestion accelerator according to  claim 4 , wherein a mass ratio between the quaternary ammonium compound and the sulfur-containing compound is 1:2 to 100:1. 
     
     
         9 . A method for producing pulp, the method comprising a digestion step of adding at least one main agent selected from the group consisting of an alkaline main agent and a sulfite-based main agent, and a digestion accelerator, to digest a material including lignocellulose,
 wherein the digestion accelerator is the digestion accelerator according to  claim 3 .   
     
     
         10 . The method for producing pulp according to  claim 9 , wherein a content of the digestion accelerator is 0.001% by mass to 1.0% by mass relative to the material including the lignocellulose.