Compositions and methods for differential release of 1-methylcyclopropene
A clathrate of 1-methylcyclopropene with α-cyclodextrin, obtained as a solid particulate product, is modified by comminuting, classifying, or both to obtain a modified particulate. When subjected to identical atmospheric disgorgement conditions of humidity and temperature, identical masses of the modified and unmodified particulates exhibit different rates of 1-methylcyclopropene disgorgement. Specifically, we have found that a smaller mean particle size is inversely related to a greater rate of 1-methylcyclopropene release.
1. A particulate composition consisting essentially of a mixture of a first particulate portion and a second particulate portion, wherein
i) the first particulate portion is a modified portion of a source particulate and has a mean particle size between 1 μm and 10 μm, or between 10 μm and 20 μm as determined by a volume-based method, and the second particulate portion is an unmodified portion of the source particulate and has a mean particle size between 30 μm and 100 μm, as determined by a volume-based method, wherein the source particulate consists essentially of a 1-methylcyclopropene clathrate of α-cyclodextrin;
ii) the first particulate portion and the second particulate portion have a first rate of 1-methylcyclopropene release and a second rate of 1-methylcyclopropene release, respectively, when subjected to a set of disgorgement conditions; and
iii) the particulate composition has a rate of 1-methylcyclopropene release that is intermediate between said first rate of 1-methylcyclopropene release and said second rate of 1-methylcyclopropene release when subjected to said set of disgorgement conditions.
2. The particulate composition of claim 1 wherein the volume-based method is light scattering.
3. The particulate composition of claim 1 wherein the first particulate portion has a mean particle size between 1 μm and 3 μm, between 2 μm and 4 μm, between 3 μm and 5 μm, between 4 μm and 6 μm, between 5 μm and 7 μm, between 6 μm and 8 μm, between 7 μm and 9 μm, between 8 μm and 10 μm, between 10 μm and 12 μm, between 11 μm and 13 μm, between 12 μm and 14 μm, between 13 μm and 15 μm, between 1 μm and 5 μm, between 5 μm and 10 μm, between 10 μm and 15 μm, between 15 μm and 20 μm, between 2 μm and 10 μm, between 3 μm and 10 μm, between 3 μm and 9 μm, between 3 μm and 8 μm, or between 3 μm and 7 μm.
4. The particulate composition of claim 1 wherein the first particulate portion mean particle size is about 4 μm.
5. The particulate composition of claim 1 wherein the first particulate portion mean particle size is about 5 μm.
6. The particulate composition of claim 1 wherein the first particulate portion mean particle size is about 6 μm.
7. The particulate composition of claim 1 wherein the first particulate portion mean particle size is about 7 μm.
8. The particulate composition of claim 1 wherein the second particulate portion has a mean particle size between 40 μm and 70 μm.
9. The particulate composition of claim 1 wherein the particulate composition comprises about 1 to 1000 parts by weight of the first particulate portion and about 1 to 1000 parts by weight of the second particulate portion.
10. The particulate composition of claim 1 wherein the mixture has a bimodal mean particle size distribution.
11. The particulate composition of claim 1 wherein the disgorgement conditions are a pressure of about 1 atm, a temperature between 0° C. and about 50° C., and a relative humidity between about 80% and 100%.
12. The particulate composition of claim 1 , wherein a portion of the source particulate is comminuted to produce the first particulate portion.
13. The particulate composition of claim 1 , wherein a portion of the source particulate is classified to produce the first particulate portion.
14. A method of disgorging 1-methylcyclopropene gas from the particulate composition according to claim 1 , the method comprising
a. obtaining the particulate composition comprising the mixture of the first particulate portion and the second particulate portion; and
b. situating the particulate composition proximal to a living plant or portion thereof.
15. A method of making the particulate composition according to claim 1 , the method comprising:
a. obtaining a source particulate consisting essentially of a 1-methylcyclopropene clathrate of α-cyclodextrin, the source particulate having a mean particle size between 30 μm and 100 μm as determined by a volume-based method;
b. modifying a first portion of the source particulate to provide a first particulate portion having a mean particle size between 1 μm and 10 μm, or between 10 μm and 20 μm as determined by the volume-based method; and
c. admixing at least a portion of the first particulate portion with at least a portion of the source particulate to obtain the particulate composition.