€8% 
Table II. The hydrolysis constant is in K-100(h-¢). 
In parenthesis, the half-life in days. All measurements were made at pH 1-5 where 
the compounds exhibit greatest stability. At this pH the solution had minimal 
effects on hydrolysis (continued) 
COMPOUND 0° 10° 20° 30° 40° 50° 60° 70° 
Prep. S 404 (XXVIII) 0.00055 0.0027 0.0125 0.047 0.170 0.53 1.53 4.91 
(5200) (1070) (240) (63) (18) 5:25) (1.9) (0.59) 
Disyston (XI) 0.00012 0.0006 0.0026 0.010 0.037 0.12 O.37 1.06 
(23200) (4830) (1110) (290) (78) (24) (7.8) (2.7) 
Guthion (1X) 0.00055 0.0027 0.012 0.047 0, 16 0.53 1. 53 41D 
(5200) (1070) (240) (61.5) (18) (5.46) (1.9) (0.61) 
PO-Guthion (XXIX) 0.002 0.008 0.035 0.13 0.45 1.45 4.93 13.8 
(1450) (360) (82.5); *@2272) (6.4) (2.0) (0.585) (0.21) 
Dipterex (XIII) 0.00025 0.0012 0.0055 0.0207 £40.07 0.27 0.90 2.56 
(11600) (2400) (526) (140) (41) (10.7) (3.2) (1.13) 
DDVP (IIL) 0.0028 0.012 0.047 0.167 0.503 1.745 3.03 17.6 
(1030) (240) 61,5). (7.3) (5.8) (1.66) (0.58) (O. 64) 
Chlorthion (XIX) 0.001 0.0048 0.021 0.08 0.286 0:95 2493 8.34 
(2900) (600) (138) (36) (10) (3.0) (1) (0.35) 
Methyl-E 605 (XVIII) 0.0008 0.0038 0.0165 0.064 0.230 0.72 2.16 6), PZ 
(3600) (760) (175) (45) (12.5) (4.0) (1.34 (0.47) 
Thimet (XII) 0.014 0.08 0.4 L833 7.14 - - ~ 
(200) (36) C722) (1.6) (0.4) ~ - - 

K30° 
K20° 

3.85 
i Ber 
3.60 
3.8 
3.85 
4.6 
