Thermodynamically stable crystal modification of 2-methyl-N-(5-methyl-1, 3, 4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide
A thermodynamically stable crystal modification of 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide is described. This thermodynamically stable crystal modification has particular advantages in the stability of suspension formulations.
1. A thermodynamically stable crystal modification A of 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide, wherein the crystal modification
a) has an X-ray powder diffractometry pattern with the following peaks, measured at a copper anode at a K-alpha1 radiation of 1.54060 Ångstrom, specified in degrees 2 theta:
9.2
23.0
30.6
10.4
23.4
31.6
11.4
23.9
32.3
12.4
24.9
32.8
12.6
25.4
33.7
14.0
25.7
33.9
17.5
25.7
34.4
17.7
26.4
35.0
17.9
27.2
35.1
18.3
27.3
35.6
19.3
27.8
35.8
20.1
28.0
36.2
20.6
28.6
36.7
21.2
29.4
36.8
21.8
29.6
37.3
22.3
29.8
37.6
22.8
30.3
37.8
and
b) has a Raman spectrum with band maxima specified in [cm −1 ], of:
3080
1267
603
3066
1214
584
3039
1194
566
3030
1156
544
3009
1148
530
2948
1136
508
2928
1109
477
1719
1066
469
1681
1010
428
1618
965
404
1592
957
382
1577
909
359
1563
868
303
1545
803
288
1445
772
270
1412
758
231
1404
746
186
1391
720
154
1330
710
143
1303
672
105.
2. A herbicidal composition comprising a content of the thermodynamically stable crystal modification A of 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide as claimed in claim 1 and one or more standard extenders and/or surface-active auxiliaries.
3. The herbicidal composition as claimed in claim 2 , wherein the 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide is present to an extent of more than 90% by weight in the stable crystal modification A.
4. The herbicidal composition as claimed in claim 3 , wherein the 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide is present to an extent of more than 95% by weight in the stable crystal modification A.
5. The herbicidal composition comprising the thermodynamically stable crystal modification A of 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide as claimed in claim 1 and a metastable crystal modification, wherein the 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide is present to an extent of more than 90% by weight in the stable crystal modification A.
6. The herbicidal composition as claimed in claim 5 , wherein the 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methyl sulfonyl)-4-(trifluoromethyl)benzamide is present to an extent of more than 95% by weight in the stable crystal modification A.
7. The herbicidal composition as claimed in claim 4 , wherein the 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide is present to an extent of more than 98% by weight in the stable crystal modification A.
8. A product comprising the thermodynamically stable crystal modification A of 2-methyl-N-(5-methyl-1,3,4-oxadiazol-2-yl)-3-(methylsulfonyl)-4-(trifluoromethyl)benzamide as claimed in claim 1 or a composition thereof for controlling unwanted plants.
9. A method for controlling one or more unwanted plants, comprising allowing the thermodynamically stable crystal modification A as claimed in claim 1 or a composition thereof to act on the unwanted plants and/or a habitat thereof.
10. The method as claimed in claim 9 for controlling harmful plants in monocotyledonous plant crops.
11. The method as claimed in claim 9 in which the plant crops are genetically modified or have been obtained by mutation-selection.