Basic clay catalyst for the production of glycol monoester

Abstract

The invention is a base-modified clay that selectively catalyzes the formation of a glycol monoester from an aldehyde. The base-modified clay comprises a clay having secluded conjugate base sites and exchangeable interstitial cationic spaces. In the base-modified clay, the interstitial hydroxyl groups have been converted to oxide sites, at least one structural hydroxyl group has been converted to an oxide site. The base-modified clay contains sufficient conjugate base cations to balance the charge of said oxide groups. Processes for preparing the base-modified clay are described. The invention also provides a process for preparing a glycol monoester. This process includes heating in a reaction vessel an aldehyde and a catalytic amount of the base-modified clay under conditions sufficient to produce a glycol monoester.

1 . A base-modified clay having secluded conjugate base sites and exchangeable interstitial cationic spaces.  
     
     
         2 . A base-modified clay of  claim 1 , wherein all interstitial hydroxyl groups have been converted to oxide sites, wherein at least one structural hydroxyl group has been converted to an oxide site, and containing sufficient base cations to balance the charge of said oxide sites.  
     
     
         3 . A base-modified clay of  claim 1 , wherein the clay is selected from the group consisting of a smectite clay, a partially exchangeable and hydrated illite clay, and a hydrated chlorite clay; 
 and the base cation is selected from the group consisting of an alkaline metal cation, an alkaline earth metal cation, and mixtures thereof.    
     
     
         4 . A base modified clay of  claim 3 , wherein the clay is selected from the group consisting of a montmorillonite clay, a beidellite clay, a nontronite clay, a saponite clay, a hectorite clay, a stevensite clay, a sepiolite-palygorskite clay, degraded illites, and hydrated chlorites; and the base cation is selected from the group consisting essentially of lithium, sodium, rubidium, cesium, and potassium.  
     
     
         5 . A base-modified clay of  claim 3 , wherein the base cation is lithium, potassium or sodium.  
     
     
         6 . A base-modified clay of  claim 3 , wherein the concentration of the base cation ranges from about 0.005 to about 20 weight percent.  
     
     
         7 . A base-modified clay of  claim 6 , wherein the concentration of the base cation ranges from 0.5 to 10 weight percent.  
     
     
         8 . A base-modified clay of  claim 1 , having a gallery width of less than about 10.2 Å.  
     
     
         9 . A process for preparing a base-modified clay comprising the step of treating a clay with a solution containing a basic anion or an uncharged species under conditions sufficient to produce a clay having secluded conjugate base sites and exchangeable interstitial cationic spaces.  
     
     
         10 . A process of  claim 9 , wherein the clay is heated in a solution containing a Brönsted base.  
     
     
         11 . A process of  claim 10 , wherein the solution is aqueous solution of an alkaline metal hydroxide.  
     
     
         12 . A process of  claim 11 , wherein the alkaline metal hydroxide is selected from lithium hydroxide, sodium hydroxide or potassium hydroxide and the clay is heated for 0.5 to 100 hours.  
     
     
         13 . A process of  claim 9 , wherein the clay is mixed with a solution of a salt or other compound having an alkaline metal and then subjected to pyrolysis or a combustion/pyrolysis process.  
     
     
         14 . A catalyst composition comprising catalytic amount of a base-modified clay according to  claim 1 .  
     
     
         15 . A catalyst composition according to  claim 14 , wherein the base-modified clay is in the form of a granule, particle, pellet, sphere, tablet, ring or extrudate.