Process for producing phenoxycarboxylic acid derivative
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a process for producing phenoxycarboxylic acid derivatives useful as agricultural chemicals. 
     2. Description of the Prior Arts 
     It has been known that phenoxycarboxylic acid derivatives can be produced by reacting a phenol compound having the formula ##STR5## wherein R represents ##STR6## and X 1  represents a hydrogen atom, a halogen atom, a lower alkyl group, trifluoromethyl group, nitro group or cyano group; X 2  represents a hydrogen atom, a halogen atom, a lower alkyl group, nitro group or cyano group, with a halogen compound having the formula 
     
         X--R&#39; 
    
     wherein R&#39; represents ##STR7## and R 1  and R 2  respectively represent a hydrogen atom or a lower alkyl group and X represents a halogen atom, in a solvent such as ketones e.g. acetone, butanone and methyl ethyl ketone; ethers e.g. tetrahydrofuran, diethyl ether, methyl butyl ether, ethyleneglycol dimethyl ether; dimethylformamide, dimethylacetamide, dimethylsulfoxide, benzene, toluene and hexane, in the presence of a dehydrogenhalide agent of an alkali metal compound such as sodium or potassium compound or an alkaline earth metal compound such as calcium or magnesium compound. This is disclosed in Japanese Unexamined Patent Publication No. 22432/1973, 125228/1976, 32730/1976, and 87173/1977. 
     However, a dehydrogenhalidation of the halogen compound is caused by this process. Thus, a large amount of the halogen compound should be used and a large amount of the by-products is produced to cause low yield of the object compound. 
     The inventors have studied to obtain a phenoxycarboxylic acid derivative having high purity in high yield. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a process for producing a phenoxycarboxylic acid derivative having high purity in high yield by preventing side reactions. 
     The foregoing and other objects of the present invention have been attained by reacting a phenol compound having the formula ##STR8## wherein R represents ##STR9## and X 1  represents a hydrogen atom, a halogen atom, a lower alkyl group, trifluoromethyl group, nitro group or cyano group; X 2  represents a hydrogen atom, a halogen atom, a lower alkyl group, nitro group or cyano group, with a halogen compound having the formula 
     
         X--R&#39;                                                      (II) 
    
     wherein R&#39; represents ##STR10## and R 1  and R 2  respectively represent a hydrogen atom or a lower alkyl group; and X represents a halogen atom, in the presence of a quaternary ammonium salt or a quaternary phosphonium salt and in the presence of a base of an alkali metal compound or an alkaline earth metal compound to produce a phenoxycarboxylic acid derivative having the formula wherein R and R&#39; are defined above. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The phenol compounds having the formula (I) used in the present invention are the compounds having the formula ##STR11## wherein X 1  and X 2  is the same or different and respectively represents a hydrogen atom; a halogen atom such as chlorine, bromine, fluorine or iodine atom; a lower alkyl group such as methyl, ethyl, i-propyl or t-butyl group; trifluoromethyl group; nitro group; or cyano group. 
     Suitable phenol compounds (I) include 4-phenoxyphenol, 4-(2-chlorophenoxy)phenol, 4-(4-chlorophenoxy)phenol, 4-(4-bromophenoxy)phenol, 4-(3-methylphenoxy)phenol, 4-(4-methylphenoxy)phenol, 4-(3-trifluoromethylphenoxy)phenol, 4-(4-trifluoromethylphenoxy)phenol, 4-(2,5-dichlorophenoxy)phenol, 4-(3,4-dichlorophenoxy)phenol, 4-(3,5-dichlorophenoxy)phenol, 4-(4-chloro-3-methylphenoxy)phenol, 4-(4-chloro-2-methylphenoxy)phenol, 4-(2-bromo-4-trifluoromethylphenoxy)phenol, 4-(2-chloro-4-trifluoromethylphenoxy)phenol, 4-(4-chloro-2-nitrophenoxy)phenol, 4-(4-chloro-2-cyanophenoxy)phenol, 4-(5-methyl-2-isopropylphenoxy)phenol, 4-(4-trifluoromethyl-2-nitrophenoxy)phenol, 4-(2-cyano-4-trifluoromethylphenoxy)phenol, 4-(4-cyano-2-nitrophenoxy)phenol, 4-(5-chloropyridyl-2-oxy)phenol, 4-(5-bromopyridyl-2-oxy)phenol, 4-(5-iodopyridyl-2-oxy)phenol, 4-(3,5-dichloropyridyl-2-oxy)phenol, 4-(3,5-dibromopyridyl-2-oxy)phenol and 4-(3,5-diiodopyridyl-2-oxy)phenol. 
     The halogen compounds used in the present invention are the compounds having the formula (II) wherein R&#39; represents ##STR12## and R 1  and R 2  respectively represent a hydrogen atom; a lower alkyl group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, or i-butyl group; X represents a halogen atom such as chlorine, bromine or iodine atom. 
     Suitable halogen compounds (II) include 2-bromopropanoic acid, 2-chloropropanoic acid, methyl 2-bromopropanoate, ethyl 2-bromopropanoate, ethyl 2-chloropropanoate, propyl 2-bromopropanoate, propyl 2-chloropropanoate, butyl 2-bromopropanoate, butyl 2-chloropropanoate, 2-bromobutanoic acid, 2-chlorobutanoic acid, methyl 2-bromobutanoate, methyl 2-chlorobutanoate, ethyl 2-bromobutanoate, ethyl 2-chlorobutanoate, propyl 2-bromobutanoate, propyl 2-chlorobutanoate, butyl 2-bromobutanoate, butyl 2-chlorobutanoate, 2-bromopentanoic acid, 2-chloropentanoic acid, methyl 2-bromopentanoate, methyl 2-chloropentanoate, ethyl 2-bromopentanoate, ethyl 2-chloropentanoate, propyl 2-bromopentanoate, propyl 2-chloropentanoate, butyl 2-bromopentanoate, butyl 2-chloropentanoate, 4-bromopentanoic acid, 4-chloropentanoic acid, methyl 4-bromopentanoate, methyl 4-chloropentanoate, ethyl 4-bromopentanoate, ethyl 4-chloropentanoate, propyl 4-bromopentanoate, propyl 4-chloropentanoate, butyl 4-bromopentanoate, butyl 4-chloropentanoate, 4-bromohexanoic acid, 4-chlorohexanoic acid, methyl 4-bromohexanoate, methyl 4-chlorohexanoate, ethyl 4-bromohexanoate, ethyl 4-chlorohexanoate, propyl 4-bromohexanoate, propyl 4-chlorohexanoate, butyl 4-bromohexanoate, butyl 4-chlorohexanoate, 4-bromoheptanoic acid, 4-chloroheptanoic acid, methyl 4-bromoheptanoate, methyl 4-chloroheptanoate, ethyl 4-bromoheptanoate, ethyl 4-chloroheptanoate, propyl 4-chloroheptanoate, butyl 4-bromoheptanoate, butyl 4-chloroheptanoate, 4-bromo-2-pentenoic acid, 4-chloro-2-pentenoic acid, methyl 4-bromo-2-pentenoate, methyl-4-chloro-2-pentenoate, ethyl 4-bromo-2-pentenoate ethyl 4-chloro-2-pentenoate, propyl 4-bromo-2-pentenoate, propyl 4-chloro-2-pentenoate, butyl 4-bromo-2-pentenoate, butyl 4-chloro-2-pentenoate, 4-bromo-2-hexenoic acid, 4-chloro-2-hexenoic acid, methyl-4-bromo-2-hexenoate, methyl 4-chloro-2-hexenoate, ethyl 4-bromo-2-hexenoate, ethyl 4-chloro-2-hexenoate, propyl 4-bromo-2-hexenoate, propyl 4-chloro-2-hexenoate, butyl 4-bromo-2-hexenoate, butyl 4-chloro-2-hexenoate, 4-bromo-2-heptenoic acid, 4-chloro-2-heptenoic acid, methyl 4-bromo-2-heptenoate, methyl 4-chloro-2-heptenoate, ethyl 4-bromo-2-heptenoate, ethyl 4-chloro-2-heptenoate, propyl 4-bromo-2-heptenoate, propyl 4-chloro-2-heptenoate, butyl 4-bromo-2-heptenoate, butyl 4-chloro-2-heptenoate, 4-chloro-3-methyl-2-butenoic acid, 4-bromo-3-ethyl-2-butenoic acid, methyl 4-chloro-3-methyl-2-butenoate and propyl 4-bromo-3-methyl-2-butenoate. 
     The quaternary ammonium salts or the quaternary phosphonium salts include benzyltrialkylammonium salts, benzyltrialkylphosphonium salts, tetraalkylammonium salts, tetraalkylphosphonium salts, triphenylalkylphosphonium salts and triphenylbenzylphosphonium salts such as benzyltriethylammonium bromide, benzyltributylammonium chloride, benzyltriamylammonium chloride, benzyltrioctylammonium chloride, trioctylmethylammonium chloride, isobutyltributylammonium bromide, hexadecyltributylphosphonium bromide, tetrapropylammonium bromide, tetrabutylammonium chloride, tetraamylammonium bromide, tetraamylammonium chloride, tetrahexylammonium bromide and tetrabutylphosphonium chloride. It is preferable to select the quaternary ammonium salt or the quaternary phosphonium salt from benzyl tri-C 1  -C 16  alkylammonium salts, tetra-C 1  -C 16  alkylammonium salts, triphenylbenzylphosphonium salts, benzyl tri-C 1  -C 16  alkylphosphonium salts, tetra-C 1  -C 16  alkylphosphonium salts, and triphenyl C 1  -C 16  alkylphosphonium salts. 
     The alkali metal compounds or the alkaline earth metal compounds used in the present invention are the bases such as potassium hydroxide, potassium carbonate, sodium hydroxide, sodium carbonate, calcium hydroxide and magnesium oxide. It is optimum to use sodium carbonate (bicarbonate) or potassium carbonate (bicarbonate). 
     It is preferable to use a solvent so as to smoothly result the reaction. It is preferable to use a solvent being stable to the alkali metal compound or the alkaline earth metal compound, and especially an insert nonpolar solvent such as aromatic or aliphatic hydrocarbons and aromatic or aliphatic halohydrocarbons. 
     The reaction of the present invention is carried out by reacting the phenol compound having the formula (I) with the halogen compound having the formula (II) in the presence of the quaternary ammonium salt or the quaternary phosphonium salt, and in the presence of a base of the alkali metal compound or the alkaline earth metal compound in a solvent, by heating and stirring them. 
     After the reaction, an oil phase is separated from the reaction mixture by a phase separation and washed with an acid and with water and treated by a distillation or a recrystallization to obtain the object compound of the phenoxycarboxylc acid derivative (III) having high purity in high yield. 
     The halogen compound (II) is used at a molar ratio of 1.0 to 1.5 preferably 1.05 to 1.1 based on the phenol compound (I). 
     The quaternary ammonium salt or the quaternary phosphonium salt is used at a molar ratio of 0.005 to 0.05, preferably 0.008 to 0.015 based on the phenol compound (I). 
     The base of the alkali metal compound or the alkaline earth compound is used at a molar ratio of 0.5 to 1.5 based on the phenol compound (I), in a form of an aqueous solution at a desired concentration. 
     The reaction temperature is in a range of 50° to 90° C. preferably 60° to 80° C. The reaction time is depending upon the reaction temperature and is usually in a range of 4 to 8 hours. 
     In the reaction of the phenol compound (I) with the halogen compound (II), in the present invention, the dehydrogenhalide reaction of the halogen compound itself is prevented to prevent the side reactions by using at least one of the quaternary ammonium salts and the quaternary phosphonium salts such as benzyltrialkylammonium salts, benzyltrialkylphosphonium salts, tetraalkylammonium salts, tetralkylphosphonium salts, benzyltriphenylphosphonium salts, alkyl triphenylphosphonium salts whereby the phenoxycarboxylic acid derivative (III) having high purity can be obtained in high yield. 
     The process of the present invention attain excellent advantages that the phenoxycarboxylic acid derivative having high purity can be easily produced in high yield and the side reaction can be remarkably decreased. 
     The present invention will be further illustrated by certain examples and references which are provided for purposes of illustration only and are not intended to be limiting the present invention. 
     EXAMPLE 1 
     In a reactor, 100 ml of chlorobenzene and 100 ml of water were charged and then, 95.3 g (0.375 mole) of 4-(4-trifluoromethylphenoxy)phenol, 85.4 g (0.412 mole) of ethyl 4-bromo-2-pentenoate, 39.0 g (0.281 mole) of potassium carbonate and 1.1 g (0.00375 mole) of tributylethyl ammonium bromide were added. The mixture was refluxed with stirring for 6 hours to react them, and the water phase was removed and the organic phase was washed with 5% hydrochloric acid and with water and then, chlorobenzene, ethyl 4-bromo-2-pentenoate and low boiling by-products were distilled off at 100° C. under a reduced pressure of 0.02 to 0.05 mmHg to obtain 137.0 g of ethyl 4-[4-(4-trifluoromethylphenoxy)phenoxy]-2-pentenoate. The yield was 96.0%. 
     EXAMPLE 2 
     In a reactor, 100 ml of chlorobenzene and 100 ml of water were charged and 95.3 g (0.375 mole) of 4-(4-trifluoromethylphenoxy)phenol, 73.7 g (0.412 mole) of 4-bromo-2-pentenoate, 78.0 g (0.56 mole) of potassium carbonate and 1.1 g (0.00375 mole) of tributylethylammonium bromide were added. The mixture was refluxed with stirring for 6 hours. The reaction mixture was cooled to the room temperature and conc. hydrochloric acid was added to the reaction mixture with stirring to be acidic. The water phase was separated and the organic phase was washed with water and chlorobenzene was distilled off at 100° C. under a reduced pressure of 0.02 to 0.05 mmHg to obtain 4-[4-(4-trifluoromethylphenoxy)phenoxy]-2-pentenoic acid. The yield was 91.2%. 
     REFERENCE 1 
     In accordance with the process of Example 1 except that tributylethylammonium bromide was not incorporated, the mixture was refluxed with stirring for 6 hours and the reaction mixture was cooled to the room temperature and 15.0 g (0.375 mole) of sodium hydroxide was added and the mixture was further stirred for 30 minutes and the mixture was further treated to obtain 44.5 g of ethyl 4-[4-(4-trifluoromethylphenoxy)phenoxy]-2-pentenoate. The yield was 31.2%. 
     REFERENCE 2 
     In a reactor, 100 ml of ethanol was charged and 95.3 g (0.375 mole) of 4-(4-trifluoromethylphenoxy)phenol, 85.4 g (0.412 mole) of ethyl 4-bromo-2-pentenoate and 39.0 g (0.281 mole) of potassium carbonate were added. The mixture was refluxed with stirring for 6 hours to react them. Ethanol was distilled off and 100 ml of chlorobenzene and 100 ml of water were added and the mixture was stirred at the room temperature for 30 minutes. The water phase was separated and the organic phase was washed with 5% hydrochloric acid and with water and then, chlorobenzene, ethyl 4-bromo-2-pentenoate and low boiling by-products were distilled off under a reduced pressure to obtain 10.47 g of ethyl 4-[4-(4-trifluoromethylphenoxy)phenoxy]-2-pentenoate. The yield was 73.5%. 
     EXAMPLES 3 TO 39 
     In accordance with the process of Example 1 except using the phenol compounds and the halogen compounds shown in Table 1 instead of 4-(4-trifluoromethylphenoxy)phenol and ethyl 4-bromo-2-pentenoate, each reaction was carried out. The results are shown in Table 1. 
     
                       TABLE 1                                                     
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Ex-                                                                       
am-  Starting material                                                    
ple  Phenol compound    Halogen compound                                  
______________________________________                                    
3    4-(4-trifluoromethylphenoxy)                                         
                        ethyl 4-brono-2-                                  
     phenol             pentenoate                                        
4    4-(4-trifluoromethylphenoxy)                                         
                        4-bromo-2-pentenoic acid                          
     phenol                                                               
5    4-(4-trifluoromethylphenoxy)                                         
                        2-bromopropanoic acid                             
     phenol                                                               
6    4-(4-trifluoromethylphenoxy)                                         
                        ethyl 4-chloropentanoate                          
     phenol                                                               
7    4-(4-trifluoromethylphenoxy)                                         
                        ethyl 4-bromo-2-                                  
     phenol             heptenoate                                        
8    4-(4-trifluoromethylphenoxy)                                         
                        octyl 4-bromo-2-penteno-                          
     phenol             ate                                               
9    4-(3-trifluoromethyl-                                                
                        ethyl 4-bromo-2-                                  
     phenoxy) phenol    pentenoate                                        
10   4-(2-chloro-4-trifluoro-                                             
                        4-chloro-2-pentenoic acid                         
     methylphenoxy) phenol                                                
11   4-(2-nitro-4-trifluoromethyl-                                        
                        ethyl 4-bromo-2-                                  
     phenoxy) phenol    pentenoate                                        
12   4-(2-bromo-4-      ethyl 4-bromo-2-                                  
     trifluoromethylphenoxy)                                              
                        pentenoate                                        
     phenol                                                               
13   4-phenoxyphenol    4-bromo-2-pentenoic acid                          
14   4-(2-chlorophenoxy)                                                  
                        butyl 4-bromo-2-                                  
     phenol             pentenoate                                        
15   4-(4-cyanophenoxy) phenol                                            
                        ethyl 4-bromo-2-                                  
                        pentenoate                                        
16   4-(2,4-dichlorophenoxy)                                              
                        ethyl 2-chloropropanoate                          
     phenol                                                               
17   4-(2-nitro-4-chlorophenoxy)                                          
                        isopropyl 2-bromo-                                
     phenol             propanoate                                        
18   4-(2-chloro-4-nitro-                                                 
                        ethyl 2-bromoacetate                              
     phenoxy) phenol                                                      
19   4-(2-nitro-4-chloro-                                                 
                        ethyl 4-bromo-2-                                  
     phenoxy) phenol    butenoate                                         
20   4-(4-nitrophenoxy) phenol                                            
                        ethyl 2-bromobutanoate                            
21   4-(4-bromophenoxy) phenol                                            
                        isopropyl 4-bromo-2-                              
                        pentenoate                                        
22   4-(3,5-dichloropyridyl-                                              
                        ethyl 2-bromopropanoate                           
     2-oxy) phenol                                                        
23   4-(3,5-dichloropyridyl-                                              
                        butyl 4-bromo-2-                                  
     2-oxy) phenol      pentenoate                                        
24   4-(5-nitropyridyl-2-                                                 
                        ethyl 2-bromopropanoate                           
     oxy) phenol                                                          
25   4-(5-nitropyridyl-2-                                                 
                        ethyl 4-bromo-2-                                  
     oxy) phenol        pentenoate                                        
26   4-phenoxyphenol    methyl 4-chloro-3-                                
                        methyl-2-butenoate                                
27   4-(4-chlorophenoxy) phenol                                           
                        isopropyl 4-bromo-3-                              
                        methyl-2-butenoate                                
28   4-(5-methyl-2-isopropyl-                                             
                        2-chloropropanoic acid                            
     phenoxy) phenol                                                      
29   4-(3-methylphenoxy) phenol                                           
                        2-chloropropanoic acid                            
30   4-(4-chloro-3-methylphenoxy)                                         
                        2-chloropropanioc acid                            
     phenol                                                               
31   4-(4-trifluoromethyl-                                                
                        isobutyl 2-bromo-                                 
     phenoxy) phenol    propanoate                                        
32   4-(2-bromo-4-trifluoro-                                              
                        ethyl 2-bromo-                                    
     methylphenoxy) phenol                                                
                        propanoate                                        
33   4-(5-bromopyridyl-2-oxy)                                             
                        2-chloroacetic acid                               
     phenol                                                               
34   4-(3,5-dibromopyridyl-                                               
                        2-bromopropanoic acid                             
     2-oxy) phenol                                                        
35   4-(3,5-dichloropyridyl-                                              
                        methyl 2-chloroacetate                            
     2-oxy) phenol                                                        
36   4-(5-chloropyridyl-2-                                                
                        methyl 2-bromo-                                   
     oxy) phenol        propanoate                                        
37   4-(3,5-diiodopyridyl-                                                
                        ethyl 2-bromo-                                    
     2-oxy) phenol      propanoate                                        
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                       TABLE 1                                                     
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Ex-  Product                                                              
am-  Phenoxycarboxylic acid                                               
                          Physical   Yield                                
ple  derivative           property   (%)                                  
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3    ethyl 4-[4-(4-trifluoromethyl-                                       
     phenoxy) phenoxy]-2-penteno-                                         
                          n.sub.D.sup.20 1.5195                           
                                     96.0                                 
     ate                                                                  
4    4-[4-(4-trifluoromethyl-                                             
     phenoxy) phenoxy]-2-pentenoic                                        
                          n.sub.D.sup.20 1.5119                           
                                     91.2                                 
     acid                                                                 
5    2-[4-(4-trifluoromethylphenoxy)                                      
                          m.p.                                            
     phenoxy]propanoic acid                                               
                          136-138° C.                              
                                     90.5                                 
6    ethyl 4-[4-(4-trifluoromethyl-                                       
     phenoxy) phenoxy]pentanoate                                          
                          n.sub.D.sup.20 1.5080                           
                                     94.5                                 
7    ethyl 4-[4-(4-trifluoromethyl-                                       
     phenoxy) phenoxy]pentanoate                                          
                          n.sub.D.sup.20 1.5103                           
                                     95.0                                 
8    octyl 4-[4-(4-trifluoromethyl-                                       
     phenoxy) phenoxy]-2-pentenoate                                       
                          n.sub.D.sup.20 1.5045                           
                                     96.5                                 
9    ethyl 4-[4-(3-trifluoromethyl-                                       
     phenoxy) phenoxy]-2-pentenoate                                       
                          n.sub.D.sup.20 1.5155                           
                                     96.0                                 
10   4-[4-(2-chloro-4-trifluoro-                                          
                          m.p.                                            
     methylphenoxy) phenoxy]-2-                                           
                          88-89° C.                                
                                     87.3                                 
     pentenoic acid                                                       
11   ethyl 4-[4-(2-nitro-4-trifluoro-                                     
     methylphenoxy) phenoxy]-2-                                           
                          n.sub.D.sup.20 1.5343                           
                                     95.6                                 
     pentenoate                                                           
12   ethyl 4-[4-(2-bromo-4-trifluoro-                                     
     methylphenoxy) phenoxy]-2-                                           
                          n.sub.D.sup.20 1.5341                           
                                     96.0                                 
     pentenoate                                                           
13   4-(4-phenoxyphenoxy)-2-                                              
                          m.p.                                            
     pentenoate           113-114° C.                              
                                     94.7                                 
14   butyl 4-[4-(2-chlorophenoxy)                                         
     phenoxy]-2-pentenoate                                                
                          n.sub.D.sup.20 1.5547                           
                                     95.1                                 
15   ethyl 4-[4-(4-cyanophenoxy)                                          
     phenoxy]-2-pentenoate                                                
                          n.sub.D.sup.20 1.5625                           
                                     93.7                                 
16   ethyl 2-[4-(2,4-dichlorophenoxy)                                     
     phenoxy]propanoate   n.sub.D.sup.20 1.5601                           
                                     90.0                                 
17   isopropyl 2-[4-(2-nitro-4-                                           
     chlorophenoxy) phenoxy]pro-                                          
                          n.sub.D.sup. 20 1.5605                          
                                     97.1                                 
     panoate                                                              
18   ethyl 2-[4-(2-chloro-4-nitro-                                        
                          m.p.                                            
     phenoxy) phenoxy]acetate                                             
                          92-95° C.                                
                                     97.0                                 
19   ethyl 4-[4-(2-nitro-4-chloro-                                        
     phenoxy) phenoxy]-2-butenoate                                        
                          n.sub.D.sup.20 1.5790                           
                                     97.5                                 
20   ethyl 2-[2-(4-nitrophenoxy)                                          
     phenoxy]butanoate    n.sub.D.sup.20 1.5701                           
                                     94.3                                 
21   isopropyl 4-[4-(4-bromophenoxy)                                      
     phenoxy]-2-pentenoate                                                
                          n.sub.D.sup.20 1.5724                           
                                     95.0                                 
22   ethyl 2-[4-(3,5-dichloropyridyl-                                     
     2-oxy) phenoxy]propanoate                                            
                          n.sub.D.sup.20 1.5603                           
                                     90.2                                 
23   butyl 4-[4-(3,5-dichloropyridyl-                                     
     2-oxy) phenoxy]-2-pentenoate                                         
                          n.sub.D.sup.20 1.5565                           
                                     92.7                                 
24   ethyl 2-[4-(5-nitropyridyl-2-                                        
     oxy) phenoxy]propanoate                                              
                          n.sub.D.sup.20 1.5557                           
                                     91.3                                 
25   ethyl 4-[4-(5-nitropyridyl-2-                                        
     oxy) phenoxy]-2-pentenoate                                           
                          n.sub.D.sup.20 1.5684                           
                                     89.2                                 
26   methyl 4-(4-phenoxyphenoxy)-3-                                       
                          m.p.                                            
     methy-2-butenoate    55-56° C.                                
                                     91.0                                 
27   isopropyl 4-[4-(4-chlorophenoxy)                                     
                          m.p.                                            
     phenoxy]-3-methyl-2-butenoate                                        
                          49-50° C.                                
                                     98.0                                 
28   2-[4-(5-methyl-2-isopropylphe-                                       
                          m.p.                                            
     noxy) phenoxy]propanoic acid                                         
                          91-92° C.                                
                                     91.1                                 
29   2-[4-(3-methylphenoxy) phenoxy]                                      
                          m.p.                                            
     propanoic acid       78-79° C.                                
                                     92.5                                 
30   2-[4-(4-chloro-3-methylphenoxy)                                      
                          m.p.                                            
     phenoxy]propanoic acid                                               
                          128-129° C.                              
                                     90.5                                 
31   isobutyl 2-[4-(4-trifluoro-                                          
                          m.p.                                            
     methylphenoxy) phenoxy]propano-                                      
                          55-57° C.                                
                                     90.8                                 
     ate                                                                  
32   ethyl 2-[4-(2-bromo-4-trifluoro-                                     
     methylphenoxy) phenoxy]propano-                                      
                          n.sub.D.sup.20 1.5541                           
                                     91.1                                 
     ate                                                                  
33   2-[4-(5-bromopyridyl-2-oxy)                                          
                          m.p.                                            
     phenoxy]acetic acid  130-132° C.                              
                                     93.1                                 
34   2-[4-(3,5-dibromopyridyl-2-                                          
                          m.p.                                            
     oxy) phenoxy]propanoic acid                                          
                          68-70° C.                                
                                     90.3                                 
35   methyl 2-[4-(3,5-dichloropyridyl-                                    
                          m.p.                                            
     2-oxy) phenoxy]acetate                                               
                          52-54° C.                                
                                     93.7                                 
36   methyl 2-[4-(5-chloropyridyl-                                        
                          m.p.                                            
     2-oxy) phenoxy]propanoate                                            
                          88-90° C.                                
                                     92.0                                 
37   ethyl 2-[4-(3,5-diiodopyridyl-                                       
                          m.p.                                            
     2-oxy) phenoxy]propanoate                                            
                          85-87° C.                                
                                     90.0                                 
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     EXAMPLES 38 TO 48 
     In accordance with the process of Example 1 except replacing tributylethylammonium bromide by the other quaternary ammonium salt or phosphonium salt shown in Table 2, ethyl 4-[4-(4-trifluoromethylphenoxy)phenoxy]-2-pentenoate was produced. The results are shown in Table 2. 
     
                       TABLE 2                                                     
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Example  Quaternary salt        Yield (%)                                 
______________________________________                                    
38       benzyltrimethylammonium chloride                                 
                                93.5                                      
39       benzyltriethylammonium bromide                                   
                                95.2                                      
40       benzyltrioctylammonium chloride                                  
                                94.1                                      
41       benzyltriphenylphosphonium chloride                              
                                94.7                                      
42       tetraethylammonium bromide                                       
                                94.5                                      
43       tetrabutylammonium bromide                                       
                                94.5                                      
44       tetrahexylammonium bromide                                       
                                93.2                                      
45       trioctylmethylammonium chloride                                  
                                94.1                                      
46       tetrabutylphosphonium bromide                                    
                                95.0                                      
47       methyltriphenylphosphonium bromide                               
                                94.7                                      
48       butyltriphenylphosphonium bromide                                
                                94.3                                      
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     EXAMPLES 49 TO 56 
     In accordance with the process of Example 1 except replacing chlorobenzene by the other nonpolar solvent shown in Table 3, ethyl 4-[4-(4-trifluoromethylphenoxy)phenoxy]-2-pentenoate was produced. The results are shown in Table 3. 
     
                       TABLE 3                                                     
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Example     Solvent             Yield (%)                                 
______________________________________                                    
49          benzene             95.0                                      
50          toluene             95.1                                      
51          xylene              94.7                                      
52          dichlorobenzene     94.5                                      
53          chloroform          94.0                                      
54          carbon tetrachloride                                          
                                94.1                                      
55          n-hexane            94.0                                      
56          cyclohexane         93.7                                      
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     EXAMPLE 57 
     In accordance with the process of Example 1 except using 67.0 g (0.412 mole) ethyl 4-chloro-2-pentenoate instead of 85.4 g (0.412 mole) of ethyl 4-bromo-2-pentenoate, ethyl 4-[4-(4-trifluoromethylphenoxy)phenoxy]-2-pentenoate was obtained. The yield was 83.4%.