Methods and systems to form propylene chlorohydrin and propylene oxide

Abstract

There are provided methods and systems to form propylene chlorohydrin by hydrolysis of 1,2-dichloropropane and to further form propylene oxide from propylene chlorohydrin.

What is claimed is: 
     
         1 . A method to form propylene chlorohydrin (PCH), comprising:
 (i) contacting an anode with an anode electrolyte in an electrochemical cell wherein the anode electrolyte comprises metal chloride and saltwater; contacting a cathode with a cathode electrolyte in the electrochemical cell; applying voltage to the anode and the cathode and oxidizing the metal chloride with metal ion in a lower oxidation state to a higher oxidation state at the anode;   (ii) withdrawing the anode electrolyte from the electrochemical cell and chlorinating propylene with the anode electrolyte comprising metal chloride with metal ion in higher oxidation state and the saltwater to result in one or more products comprising PCH and 1,2-dichloropropane (DCP), and the metal chloride with the metal ion in lower oxidation state;   (iii) extracting the one or more products comprising PCH and DCP from aqueous medium by extracting with DCP as an extraction solvent; and   (iv) hydrolyzing the DCP with water to form the PCH.   
     
     
         2 . The method of  claim 1 , wherein the DCP as the extraction solvent is the DCP separated and recirculated from the same process and/or is DCP from other sources. 
     
     
         3 . The method of  claim 1 , wherein amount of the DCP in the hydrolysis is between about 10-95% by volume. 
     
     
         4 . The method of  claim 1 , further comprising after extraction, transferring aqueous medium comprising the metal chloride with metal ions in the higher oxidation state and the lower oxidation state to the oxychlorination reaction and oxidizing the metal ion of the metal chloride from the lower oxidation state to the higher oxidation state in presence of an oxidant. 
     
     
         5 . The method of  claim 4 , wherein the oxidant is X 2  gas alone; or HX gas and/or HX solution in combination with gas comprising oxygen or ozone; or hydrogen peroxide; or HXO or salt thereof; or HXO 3  or salt thereof; or HXO 4  or salt thereof; or combinations thereof, wherein each X independently is a halogen selected from fluorine, chlorine, iodine, and bromine. 
     
     
         6 . The method of  claim 5 , further comprising forming HCl by the hydrolysis of the DCP to the PCH; separating the HCl; and transferring the HCl to the oxychlorination reaction; and/or adding other HCl to the oxychlorination reaction. 
     
     
         7 . The method of  claim 4 , further comprising recirculating the metal chloride with the metal ion in the higher oxidation state back to the chlorination reaction and/or to the electrochemical cell. 
     
     
         8 . The method of  claim 1 , wherein the PCH is formed with selectivity of between about 20-100% by wt and/or more than 0.01 STY. 
     
     
         9 . The method of  claim 1 , further comprising after hydrolysis, transferring organic medium comprising PCH and DCP to epoxidation; and epoxidizing the PCH with a base to form PO in presence of the DCP. 
     
     
         10 . The method of  claim 9 , wherein the base is selected from alkali metal hydroxide, alkali metal oxide, alkaline earth metal hydroxide, alkaline earth metal oxide, or metal hydroxychloride species of stoichiometry M x   n+ Cl y (OH) (nx-y) . 
     
     
         11 . The method of  claim 10 , wherein the base is between about 5-38 wt %. 
     
     
         12 . The method of  claim 9 , wherein the reaction forms between about 5-40 tonnes of brine per tonne of PO. 
     
     
         13 . The method of  claim 1 , wherein the saltwater comprises alkali metal chloride or alkaline earth metal chloride. 
     
     
         14 . The method of  claim 1 , wherein metal ion in the metal chloride is selected from the group consisting of iron, chromium, copper, tin, silver, cobalt, uranium, lead, mercury, vanadium, bismuth, titanium, ruthenium, osmium, europium, zinc, cadmium, gold, nickel, palladium, platinum, rhodium, iridium, manganese, technetium, rhenium, molybdenum, tungsten, niobium, tantalum, zirconium, hafnium, and combination thereof. 
     
     
         15 . The method of  claim 1 , wherein the metal chloride is copper chloride. 
     
     
         16 . The method of  claim 9 , further comprising adding other DCP to the chlorination; to the hydrolysis; and/or to the epoxidation for the extraction. 
     
     
         17 . The method of  claim 16 , wherein the other DCP is obtained from a traditional chlorohydrin process and/or from direct chlorination of propylene with chlorine. 
     
     
         18 . A system to form PO, comprising:
 (i) an electrochemical cell comprising an anode chamber comprising an anode and an anode electrolyte wherein the anode electrolyte comprises metal chloride and saltwater and the anode is configured to oxidize the metal chloride with metal ion in a lower oxidation state to a higher oxidation state; a cathode chamber comprising a cathode and a cathode electrolyte; and a voltage source configured to apply voltage to the anode and the cathode;   (ii) a chlorination reactor operably connected to the anode chamber of the electrochemical cell and configured to obtain the anode electrolyte and chlorinate propylene with the anode electrolyte comprising the metal chloride with the metal ion in the higher oxidation state in the saltwater to result in one or more products comprising DCP and the metal chloride with the metal ion in the lower oxidation state;   (iii) a hydrolysis reactor operably connected to the chlorination reactor and configured to obtain the one or more products comprising DCP from the chlorination reactor with or without the saltwater comprising metal chloride and configured to hydrolyze the DCP to PCH; and   (iv) an epoxidation reactor operably connected to the hydrolysis reactor and configured to obtain the solution comprising DCP and PCH and epoxidize the PCH to PO in presence of a base.   
     
     
         19 . The system of  claim 18 , further comprising an oxychlorination reactor operably connected to the chlorination reactor and/or the electrochemical cell;
 operably connected to the hydrolysis reactor; and   configured to obtain aqueous medium from the chlorination reactor and/or the electrochemical cell comprising the metal chloride with metal ion in the lower oxidation state and the higher oxidation state;   configured to obtain HCl produced in the hydrolysis reactor; and   configured to oxidize the metal chloride with metal ion in the lower oxidation state to the higher oxidation state using an oxidant comprising the HCl and oxygen, or hydrogen peroxide.   
     
     
         20 . The system of  claim 18 , further comprising the chlorination reactor and/or the hydrolysis reactor operably connected to a traditional chlorohydrin system and/or to another chlorination reactor chlorinating propylene with chlorine, and configured to obtain other DCP from the traditional chlorohydrin system and/or from the another chlorination reactor chlorinating propylene with chlorine.