Dispersant composition

Abstract

The present invention provides a dispersant composition that is obtained by condensing an aldehyde, preferably formaldehyde, with a sulfonated middle fraction obtained from the distillation of coal tar. The middle fraction, prior to sulfonation, includes greater than 55% to about 95% by weight naphthalene and from about 5% to less than 45% by weight of a plurality of compounds selected from the group consisting of quinoline, indene, biphenyl, indane, acenaphthene, anthracene, phenanthrene, methyl naphthalene, cresol, phenol, xylenol, and tetralin. The condensation product is reacted with a base such as sodium hydroxide to form a salt polymer having a weight average molecular weight between about 2,000 and 40,000. Salt polymers formed in accordance with the method of the invention are useful as dispersants and plasticizers in aqueous cementitious slurries.

1 . A dispersant composition comprising a water-soluble salt of a polymer that is a condensation product of: 
 an aldehyde; and    a sulfonated middle fraction of crude coal tar that distills at a temperature from about 200±10° C. to about 250±10° C. at atmospheric pressure and comprises greater than 55% to about 95% by weight naphthalene and from about 5% to less than 45% by weight of a plurality of compounds selected from the group consisting of quinoline, indene, biphenyl, indane, acenaphthene, anthracene, phenanthrene, methyl naphthalene, cresol, phenol, xylenol, and tetralin.    
     
     
         2 . The dispersant composition according to  claim 1  wherein the middle fraction comprises from 57% to about 85% by weight naphthalene and from about 15% to 43% by weight of a plurality of compounds selected from the group consisting of quinoline, indene, biphenyl, indane, acenaphthene, anthracene, phenanthrene, methyl naphthalene, cresol, phenol, xylenol, and tetralin.  
     
     
         3 . The dispersant composition according to  claim 1  wherein the middle fraction comprises from about 60% to about 75% by weight naphthalene and from about 25% to about 40% by weight of a plurality of compounds selected from the group consisting of quinoline, indene, biphenyl, indane, acenaphthene, anthracene, phenanthrene, methyl naphthalene, cresol, phenol, xylenol, and tetralin.  
     
     
         4 . The dispersant composition according to  claim 3  wherein the middle fraction comprises about 5±3% 2-methyl naphthalene, about 4±2% indane, about 3.5±2% phenol/o-cresol, about 3±2% 2,4-2,5 xylenol, up to about 2±1% by weight each of indene, 1-methyl naphthalene, quinoline, biphenyl, and 2,3 xylenol.  
     
     
         5 . The dispersant composition according to  claim 1  wherein the polymer has a weight average molecular weight of from about 2,000 to about 40,000  
     
     
         6 . The dispersant composition according to  claim 1  wherein the polymer has a weight average molecular weight of from about 7,000 to about 22,000.  
     
     
         7 . The dispersant composition according to  claim 1  wherein the polymer has a weight average molecular weight of from about 8,500 to about 15,000.  
     
     
         8 . The dispersant composition according to  claim 1  wherein the aldehyde comprises one or more selected from the group consisting of formaldehyde, paraformaldehyde, and gluteraldehyde.  
     
     
         9 . A dispersant composition formed by a process comprising: 
 providing a middle fraction of coal tar that distills at a temperature from about 200±1° C. to about 250±10° C. at atmospheric pressure and comprises greater than 55% to about 95% by weight naphthalene and from about 5% to less than 45% by weight of a plurality of compounds selected from the group consisting of quinoline, indene, biphenyl, indane, acenaphthene, anthracene, phenanthrene, methyl naphthalene, cresol, phenol, xylenol, and tetralin    sulfonating the middle fraction at a temperature that does not exceed about 90° C. to form a sulfonated middle fraction;    condensing the sulfonated middle fraction with an aldehyde to form a polymer; and    adding a base to the polymer to form a water-soluble salt.    
     
     
         10 . The dispersant composition according to  claim 9  wherein the middle fraction comprises from 57% to about 85% by weight naphthalene and from about 15% to 43% by weight of a plurality of compounds selected from the group consisting of quinoline, indene, biphenyl, indane, acenaphthene, anthracene, phenanthrene, methyl naphthalene, cresol, phenol, xylenol, and tetralin.  
     
     
         11 . The dispersant composition according to  claim 9  wherein the middle fraction comprises from about 60% to about 75% by weight naphthalene and from about 25% to about 40% by weight of a plurality of compounds selected from the group consisting of quinoline, indene, biphenyl, indane, acenaphthene, anthracene, phenanthrene, methyl naphthalene, cresol, phenol, xylenol, and tetralin.  
     
     
         12 . The dispersant composition according to  claim 11  wherein the middle fraction comprises about 5±3% 2-methyl naphthalene, about 4±2% indane, about 3.5±2% phenol/o-cresol, about 3±2% 2,4-2,5 xylenol, up to about 2±1% by weight each of indene, 1-methyl naphthalene, quinoline, biphenyl, and 2,3 xylenol.  
     
     
         13 . The dispersant composition according to  claim 9  wherein the polymer has a weight average molecular weight of from about 2,000 to about 40,000  
     
     
         14 . The dispersant composition according to  claim 9  wherein the polymer has a weight average molecular weight of from about 7,000 to about 22,000.  
     
     
         15 . The dispersant composition according to  claim 9  wherein the polymer has a weight average molecular weight of from about 8,500 to about 15,000.  
     
     
         16 . The dispersant composition according to  claim 9  wherein the aldehyde comprises one or more selected from the group consisting of formaldehyde, paraformaldehyde, and gluteraldehyde.  
     
     
         17 . A method of forming a dispersant composition for use in aqueous cementitious compositions comprising: 
 providing a middle fraction of coal tar that distills at a temperature from about 200±10° C. to about 250±10° C. at atmospheric pressure and comprises greater than 55% to about 95% by weight naphthalene and from about 5% to less than 45% by weight of a plurality of compounds selected from the group consisting of quinoline, indene, biphenyl, indane, acenaphthene, anthracene, phenanthrene, methyl naphthalene, cresol, phenol, xylenol, and tetralin    sulfonating the middle fraction at a temperature not to exceed 90° C. to form a sulfonated middle fraction;    condensing the sulfonated middle fraction with an aldehyde to form a polymer; and    adding a base to the polymer to form a water-soluble salt.    
     
     
         18 . The method according to  claim 17  further comprising adding a first portion of water to the sulfonated middle fraction prior to condensing the sulfonated middle fraction with an aldehyde.  
     
     
         19 . The method according to  claim 17  further comprising adding a second portion of water to the polymer prior to adding the base.  
     
     
         20 . The method according to  claim 17  wherein the sulfonating step is accomplished by adding a sulfonating agent to the middle fraction and wherein the molar ratio of sulfonating agent to middle fraction does not exceed 1.1:1.