CA1137775A

CA1137775A - Formulation comprising 1-triacontanol and its use as plant growth regulator

Info

Publication number: CA1137775A
Application number: CA000334688A
Authority: CA
Inventors: Andrew J. Welebir
Original assignee: Biochemical Research Corp
Current assignee: Biochemical Research Corp
Priority date: 1978-09-01
Filing date: 1979-08-29
Publication date: 1982-12-21
Also published as: AR222345A1; AU5043879A; FR2434797A1; BR7905630A; AU532567B2; IT7925411A0; GB2030138A; DE2935252A1; ES484135A1; IT1122928B

Abstract

ABSTRACT OF THE DISCLOSURE

A plant growth stimulator formulation comprises water and concentrate solution dissolved therein. The concentrate solution comprises an effective plant growth stimulating amount of 1-triacontanol dissolved in a polar organic solvent. The organic solvent may usefully be acetone. The plant may be selected from the group consisting of sweet corn, field corn, sugar cane, tomatoes, cucumbers and beans. The composition of the invention is useful in stimulating the growth of living plants.

Description

. ~ ~
The present invention relates to the preparation of long-chain carboxylic acids and alcohols. The acids are ~; not only useful in themselves but can also be used to pro-duce the alcohol l-triacontanol which can be employed to increase crop yields. Thus, the invention is also directed ~, to a chemical formulation comprising l-triacontanol for use in stimulating the growth of living plants.
To the present date, syntheses of long-chain carboxy-~, lic acids containing up to about thirty carbon atoms in a . .
~, lO straight chain have not proven to be useful economically ~l when applied to large scale production. Such pTocesses have involved a keto-acid intermediate. Some older pro-',5 cesses show very low yields and involve additions of vari-ous half esters, half acid chlorides (or halides) to organo- ~
15 metallic intermediates or beta-keto esters. While some ~-~,~ othcr methods show good yields, they produce contaminated ~ products. -'S~ The present invention is directed to the preparation of long-chain carboxylic acids which can be easily conver-ted to alcohols through ester intermediates. In this ~; , :i.j `:
"

i, , .
',, .. ~ . ., . . , ,j . .. -, ~ .

~l~ 3~7~

-2-process, shorter chain acids are converted to the acid ;~ chloride which may be further purified. The acid chloride is mixed with an enamine and a hindered tertiary amine iTI an organic solvent and then acidified to form the beta-diketone after washing the organic phase and removal o-f the solvent. The beta-diketone is reacted with an inorganic hydroxide or alkali metal alkoxide and acidified to produce the keto acid which can be readily converted to the respec-tive aliphatic acid and alcohol.
The present invention thus pro~ides a process for the preparation o~ long-chain carboxylic acids and alcohols which comprises:
reacting a 21 to 30 carbon carboxylic acid with a chlorinating agent to form the acid chloride;
separating the acid ch:loride and reacting it with an enamine and a hindered tertiary amine in an organic solvent while maintaining the reaction temper-ature at 30 to 60C ;
removing the solvent and recoveTing the beta-diketone product;
reacting the beta-diketone with a solution of an alkali metal hydroxide or alkoxide and alcohol; and recovering the precipitated product.
The preferred starting short-chain acid is lignoceric 25 acid, CH3~CH2)22COO}I, which is used to make 7-keto-l-tria-contanoic acid and l-triacontanoic acid as well as l-tria-' contanol. Other short-chain acids can be used to prepare ; different long-chain carboxylic acids and alcohols contain-; ing from 28 to 36 carbon atoms such as octacosanoic acid and octacosanol and hexatriacontanoic acid and hexatria-~! contanol.
, In the preparation of long-chain carboxylic acids in accordance with the in~ention, shorter-chain starting acids are first treated with thionyl chloride, phosphorus tri-chloride or phosphorus pentachloride for up to 5 hours at ~,....

~L ~ 3~ ~'7~

-3-temperatures from 30 to 60C in t}-e presence of sol-vents such as anhydrous chloroform, methylene chloride, or carbon tetrachloride. This produces the acic1 chlor-ide which can be separated from the excess solvent and chlorinating agent with a rotary evaporator or similar means. In a preferred embodiment, the reaction tempera-ture is from 50 to 60C. Increasing the concentrations of initial reactants will increase the yield.
The acid chloride is then dissolved in an organic solvent such as chloroform which is added to a solution of an enamine and a hindered tertiary amine such as cyclo-i hexyl dimethyla~ine or tributylamine, also in an organic solvent such as chloroform. The enamine can be l-morpho-line-l-cyclopentene, l-morpholino-l-cyclohexene or l-mor-pholino-l-cycloheptene although the six carbon enamine is preferred. The more hindered the tertiary amine, the greater is the yield. Pyridine and other less hindered amines fail to work. The reaction is maintained at 30 to 40C with an ice bath or similar means. Higher concen-trations of reactants allow higher temperatures of up toabout 60C and increase the yield. While maintaining this temperature, the resulting complex is stirred and refluxed with hydrochloric acid for 3 to 5 hours, although more rapicl stirring will reduce the reaction time. The organic phase is then separated and washed with water with the subsequent recovery of the product beta-diketone.
The beta-diketone is then added to a solution of sodium, po~assium or lithium hydroxide in alcoho1 while keeping the temperature below the boiling point. The yield of this re-action can be increased by substituting an alkoxide for thehydroxide. Sodium hydroxide is the preferred hy~roxide among the alkali metal hydroxides which can be used in this reaction. The longer chain alkoxides give ~reater yields ~o that sodium propoxide is better than sodium ethox~ide. Sodi-um is again prefer1ed over the lithium or potassium .

-4-alkoxides. Almost any alcohol of 6 carbons or less is acceptable including ethylene glycol After refluxing, the solution is cooled to 5GC to precipitate out the salt of the keto acid which is readily isolated by filtering and washing. The free acid can be prepared by merely suspending the salt in hot water and adding hydrochloric acid. If further purification is de-sired, the acid can be dissolved in heated methyl ethyl ketone and then cooled to recrystallize the purified acid.
The keto acid can be readily converted to the respec-tive carboxylic acid and alcohol by a number of di-fferent processes. For example, the Huang-~linlon reduction can be used to form the carboxylic acid.
The long-chain alcohol l-triacontanol, CH3lCH2)28CE12OH, which can be prepared in accordance with one of the aspects of this invention, has been studied recently as being a naturally occurring plant growth stimulant (Ries et al, Science, 195, 1339 (1977)). Field trials have been conduc-ted in an attempt to optimize the conditions under which a .;~ 20 chemical formulation of this compound can be applied to plants.
In the research involving the utilization of l-tria-contanol as a plant growth regulator, use has been made of a relatively large amount o surfactants in the chemical formulation in an effort to render the l-triacontanol solu-ble in water. ~s is well known, l-triacontanol is basically insoluble in water. Of course, the use of a large ainount of water is imperative in order to economically and effectively apply the chemical formulation to large areas of growing plants. Accordingly, it is imperative to render the l-tria~
contanol water-soluble so that it can be properly dispersed in a large quantity of water which is to be subsequently applied to the plants. However, the organic solvents which are presently being utilized to make the ]-triacontanol solu-ble in water, for example, chloroform and chemical

-5-surfac-tants and also other wa~er~insolllble solvents, have been found to be detrimental to both plant life and to tile environment. Thus, it has been found, for example tha-t surfactants coat the plants, thereby pre-venting entry of the l-triacontanol into the plant and, consequently, the plant growth properties of the l-tria-contanol are rendered less effective.
Accordingly, an additional objecti~e of the present invention is to provide an inexpensive and effective means for formulating l-triacontanol without the use of surfac-tants or other large quantities of organic solvents which have been found to adversely affect plant growth Speci-fically, the present invention provides a plant growth regulator formulation containing a polar organic solvent which renders the l-triacontanol soluble in water and at the same time poses no threat to plant life or to the en-vironment.
The plant growth stimulant, l-triacontanol, is dissol-ved in a polar organic solvent in an amount sufficient to ; 20 form a water-soluble concentrate. Typically, the concen-~ trate can be formed by mixing together one part by weight - of l-triacontanol with up to about S00,000 parts by volume of the polar organic solvent, and advantageously one part by weight of l-triacontanol to about l,000 parts by volume of the polar organic solvent. The polar organic solvent can be any water-soluble solvent or solvent mixture contain-ing one or more functiona] groups 7 which renders the result-ing l-triacontanol solution soluble in water, which is the major constituent in the formulation. This solution is then dissolved in a large quantity of water with stirring an~/or shaking.
Typically, the l-triacontanol-polar organic solvent concentrate-water mixture is applied t~o the growing plants in an amount sufficient to achieve a distribution of at le~st I mg of l-triacontanol per acre, advantageously 5 to !

, .: ' : , , :' ' . -7~

-6-20 mg per acre.
The polar organic solvents which are utilized in the present invention to aid in the solubility of the l-triacontanol in water include alcohols, ketones, water-soluble ethers, glycols and any otheT solvent or solventmixture containing one or more functional groups contained in any one class or classes of said solvents. Suitable polar organic solvents include acetone, methyl ethyl ketone, methanol, isopropanol, diethylene glycol, n-butanol, propy-lene glycol and dioxane.
Typical ratios of the l-triacontanol-organic solvent ; solution, on the one hand, to water, on the other hand, may vary from 1 : 10,000 to 1 : 1 parts by volume, preferably 1 : 1,000 to 1 : 100 parts by volume, depending upon the de-~ 15 sired concentration of the l-triacontanol required or de-; sired in the final solution.
The chemical formulation, according to the present in-. vention can be applied to plant life in any desired manner although the spraying of the growing plant life has been found to be particularly effective.
The formulation of the invention, when applied tofield and sweet corn, sugar cane, tomatoes, cucumbers, beans, and the like, has been found to increase production in a greenhouse-controlled environment in an amount up to about 24% based upon the dry weight of the plants. Similar tests under field conditions of 1,000 acres or more have resulted in an increase in crop yield of field corn of from about 6 to 16% measured in terms of bushels per acre.

, 30 :~ ' l 35 ;''" ~.
., ,. ~ .
:~';', .~"

- 7 -The following Examples are given merely as illustra-tive of the present invention and are not to be considered as limiting. Unless otherwise noted, the percentages ` therein are by weight.

Lignoceric acid was reacted with 3 equivalents of thionyl chloride for up to 3 hours at 50-60C in 300 ml per mole of anhydrous chloroform. Excess solvent and ~ thionyl chloride was evaporated leaving an ambeT liquid, - which was used without further purification. One mole of the acid chloride was then dissolved in 500 ml anhydrous, alcohol-free chloroform and added over 2 hours to a solu-tion of one mole of l-morpholino-l-cyclohexene and one eqwivalent of triethyl amine (a tertiary amine) in an equal volume (500 ml) of chloroform. The temperature was main-tained between 30 and 40C., and the resulting complex was stirred and refluxed Wit]l 500 ml of 3N hydrochloric acid over a 5 hour period. The organic phase was then separated and washed with water. The resultant organic phase was evaporated on a rotary evaporator leaving the beta-diketone `i as a brown oil.
The entire quantity of beta-diketone was then added to a solution of 3 mols of sodium hydroxide in 1.5 liters of ethanol over l/2 to l hour while maintaining the temperature at less than 80C. The solution was refluxed for 1 to 2 hours and then cooled to 5C. The resulting precipitate was ~ filtered and washed with methanol and then dried. The free ,~ 30 acid was prepared by suspending the salt in hot water and i acidifying to pH 2-3 with hydrochloric acid. After filter-~3 ing and washing with hot water, the product is 7-keto-l-triacontanoic acid which can be further purified by recry-stallization with methyl ethyl ketone. The crude yield was about 82~.

:~ .
.

., :

!

Lignoceric acid was reacted with 3 equivalents of thionyl chloride for 3 hours at 50-60C in 300 ml per mole of anhydrous chloroform. Excess solvent and thionyl - chloride were evaporated leaving an amber liquid, which was used without further purification. One mole of the acid chloride was then dissolved in 500 ml anhydrous, alcohol-free chloroform and added over 2 hours to a solution of one 10 mole of l-morpholino-l-cyclohexene and one equivalent of tributyl amine (a tertiary amine) in an equal volume ~500 ïnl) of chloroform. The temperature was maintained 'be-tween 30 and 40C , and the resulting complex was stirred and refluxed with 500 ml of 3N hydrochloric acid over a 15 5 hour period. The organic phase was then separated and washed with water. The resultant organic phase was evapora-ted on a rotary evaporator leaving the beta-diketone as a brown oil.
The entire quantity of beta-diketone was then added to 20 a solution of 3 mols of sodium ethoxide in 1.5 liters of methanol over 1/2 to 1 hour while maintaining the tempera^
, ture at less than 80C. The solution was refluxed for 1 to , 2 hours and then cooled to 5-10C. The resulting precipi-tate was filtered and washed with methanol and then dried.
Z5 The free acid was prepared by suspending the salt in hot water and acidifying to pH 2-3 with hydrochloric acid.
" 'After filtering and washing with hot water, the product is 7-keto-1-triacontanoic acid which can be further purified by recrystallization with methyl ethyl ketone. The crude 30 yield was about 85%. ' " :

Lignoceric acid was reacted with 2 equivalents of phosphorus pentachloride for 1 hour at 40-50C in 300 ml per mole of anhydrous chloroform. Excess solvent was re-moved by distillation while the acid chloride was then collected after further distillation in vacuo as an amber liquid after cooling. One mole of the acid chloride was then dissolved in 500 ml anhydrous, alcohol-free chloroform and added over 2 hours to a solution of one mole of l-mor-pholino-l-cyclohexene and one equivalent of triethyl amine (a tertiary amine) in an equal volume (500 ml) of chloro-form. The temperature was maintained between 30 alld 40C , and the resulting complex was stirred and re:Eluxed with 500 ml of 3N hydrochloric acid over a 5 hour period. The organic phase was then separated and washed with water. The resultant organic phase was evaporated on a rotary evapora-tor leaving the beta diketone as a brown oil.
, The entire quantity of beta-diketone was then added to .~ 15 a solution of 3 mols of potassium hydroxide in 1.5 liters ; of ethanol over 1/2 to l hour while maintaining the temper-- ature at less than 80C. The solution was refluxed for 1 to 2 hours and then cooled to 5C. The resulting precipi-tate was filtered and washed with methanol and then dried.
The free acid was prepared by suspending the salt in hot water and acidifying to pH 2-3 with hydrochloric acid.
After filterin~ and washing with hot water, the produc~ is 7-keto-1-triacontanoic acid which can be further purified ' by recrystallization with methyl ethyl ketone. The crude ', 25 yield was at least 80%.

The sodium salt of the 7-keto-1-triacontanoic acid ,, 30 (such as produced in Examples 1-3 above) in the amount of ,! o.g mol was dissolved in 1 liter of diethylene glycol at 150~C. The temperature was reduced to 130~C ; then 150 ml of hydrazine hydrate was added with the reaction mixture ` being refluxed for 3 to 4 hours to form the hydrazone.
Either at this pclint or during the previous refluxing, .~
.~

3~

about 200 grams Or potassium hydroY.ide was added to the mixture. After the refluxing, the temperature was raised to 195C and refluxing was continued for 4 to lZ hours to decompose the hydrazone to the free acid. The tempera-ture was then reduced to 100C and 2 liters of hot waterwas added whereafter the acid salt was acidified to about pH 2-3 with 6N hydrochloric acid (to form triacontanoic acid) and filtered. The triacontanoic acid can be further purified by recrystallization -from methyl ethyl ketone with a yield of 89~ at a purity of about 99% after washing with diethyl ether and a second recrystallization.

Triacontanol was prepared from triacontanoic acid by suspending 0.1 mol o:E the acid in 40 ml of anhydrous chloro-form followed by the addition of thionyl chloride while maintaining the temperature at 40C to 60C for 2 hours.
Chloroform and excess thionyl chloride were removed in a rotary evaporator, and the resulting acid chloride was re-acted with 10 ml of absolute ethanol to form the ester.
Excess ethanol was removed in a similar manner, and the ester was dissolved in 100 ml of anhydrous ether.
; Powdered lithium aluminum hydride (0.5 mol) was re-fluxed in 200 ml of anhydrous diethyl ether until most of the solid had dissolved. The solution of the ester was added slowly over 45 min. with vigorous stirring, and the reaction mixture was allowed to reflux overnight. Ethyl acetate (20 ml) was added to react with the unreacted lithi-um aluminum hydride, and the mixture was decomposed cautious-ly with 50 ml of 6N HCl with vigorous stirring. To solu-bilize the resulting alcohol, 50 ml of benzene was added, and the mixture was washed with warm water. The organic layer was filtered through anhydrous sodium sulfate, and an equal volume of acetone was added. Cooling to 5C , 7~'~

followed by filtration, produced l-triacontanol at a yield of about 86%.

S
Docosanoic acid was heated with 3 equivalents of thionyl chloride for 3 hours at 50 60C in 300 ml per mole of anhydrous chloroform. Excess solvent and thionyl chlor-ide were evaporated leaving an amber liquid, which was used without further purification. One mole of the acid chlor-, ide was then dissolved in 500 ml anhydrous, alcohol-free ! chloroform and added over 2 hours to a solution of one mole of l-morpholino-l-cyclohexene and one equivalent of diethyl cyclohexyl amine in an equal volume (500 ml) of chloroforln.
The temperature was maintained between 30 and 40C , and ~ the resulting complex was stirred and re-fluxed with 500 ml ; of 3N hydrochloric acid over a 5 hour period~ The organic phase was then separated and washed with water. The re-sultant organic phase was evaporated on a rotary evaporator leaving the beta-diketone as a brown oil.
The entire quantity of beta-diketone was then added to a solution of 3 mols of sodium hydroxide in 1.5 liters of ethanol over 1/2 to l hour while maintaining the tempera-ture at less than 80C. The solution was refluxed for l to 2 hours and then cooled to 5~C. The resulting precipitate ~', was filtered and washed with methanol and then dried. The :free acid was prepared by suspending the salt in hot wa~er and acidifying to pH 2-3 with hydrochloric acid. After filtering and washing with hot water, the product is 7-keto-l-octacosanoic acid which can be further purified by recry-stallization with methyl ethyl ketone. The crude yield was , at least 80%.
The 7-keto-l-octacosanoic acid can be converted to 1-~l octacosanoic acid in the same manner as the 7-keto-1-tri-~` 35 acontanoic acid is converted to l-triacontanoic acid in ....
.:1 "
( y .

,;
. .
, .~

3~

Example 4 and then to the corresponding alcohol as in Examples 5 and 7.
',:
~ EXAMPLE 7 The acid chloride of l-triacontanoic acid was conver-ted to the ester by adding methanol or ethanol and stirring for 1/2 to 1 hour. The alcohol was evaporated on a rotary evaporator leaving ethyl-l-triacontanoate. The ester was then reacted in a pressure vessel under about 250 atmos-pheres of hydrogen in the presence of a powdered copper chromite catalyst for about 12 hours at 250C. to produce l-triacontanol. One part of catalyst was present for every 5 to 10 parts of ester.
~ EXAMPLE 8 :'' A 1 mg quantity of l-triacontanol was dissolved in 10 ml of boiling acetone (or methyl ethyl ketone) and the solution was cooled to room temperature. This was added to ; 990 ml of water with vigorous stirring o~er a 30-second period. The resultant solution may be applied to plant life aerially at a concentration of 10 mg per acre using 10 liters of solution per acre. The solution may further be diluted with ten parts of water Tesulting in a concentra-i tion of 1 mg per acre.

., .

A 10 mg quantity of l-triacontanol was dissolved in 100 ml of methanol. The mixture was added to 900 ml of -water heated to 50C with vigorous stirring. The concen^ - ;
trate may be diluted with 9 liters of water resulting in a solution containing 1 mg per liter. This solution may be 35 ~applied as described in Example 8.

~ .

. . .

:
.

EXAMPLE IO

One mg of l-triacontanol was dissolved in 25 ml of hot isopropanol and the hot solution was poured into 975 ml of water with vigorous stirring over a one-minute period, This solution may be applied as described above in Example

8.

One mg of l triacontanol was dissolved in 25 ml of hot diethylene glycol and addecl to 975 ml of rapidly stirring water. The resulting solution may be used as described in Example 8.

One mg of l-triacontanol was dissolved in 10 ml of hot n-butanol and the mixture was added with stirring to 990 ml 20 of water at 60. The solution was cooled to room temperature before use.

:
~5 Ten mg of l-triacontanol was dissolved in 100 ml of warm dioxane and added over 60 seconds to 950 ml of warm water. The solution may be used as described in Example 8.

` 30 One mg of l-triacontanol was dissolved in 50 ml of hot propylene glycol and added to 950 ml of water with stirring.
This solution may be used as described in Example 8.

..

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A plant growth stimulator formulation comprising:
water and a concentrate solution dissolved in said water, said concentrate solution comprising an effective plant growth stimu-lating amount of 1-triacontanol dissolved in a polar organic solvent, wherein said concentrate solution and said water are present in a ratio sufficient to disperse the triacontanol in said formulation.

2. A plant growth stimulator formulation comprising:
water and concentrate solution dissolved in said water said concentrate solution comprising an effective plant growth stimu-lating amount of 1-triacontanol dissolved in a polar organic solvent wherein the ratio of concentrate to water is from 1:10,000 to 1:1 parts by volume.

3. The plant growth stimulator formulation of claim 2, wherein the concentrate comprises: one part by weight of 1-triacontanol with up to about 500,000 parts by volume of the polar organic solvent.

4. The plant growth stimulator of claim 2, wherein the polar organic solvent is selected from a group consisting of alcohol, ketones, water soluble ethers and glycols.

5. The plant growth stimulator of claim 1, wherein the ratio of concentrate to water is from 1:10,000 to 1:1 parts by volume.

6. The plant growth stimulator of claim 3, wherein the concentrate comprises: one part by weight of 1-triacontanol with up to about 1,000 parts by volume of the polar organic solvent.

7. The plant growth stimulator of claim 2, wherein the ratio of the concentrate to water is 1:1,000 to 1:100 parts by volume.

8. The plant growth stimulator of claim 2, wherein the polar organic solvent is selected from the group consisting of acetone, methyl ethyl ketone, methanol, isopropanol, diethylene glycol, n-butanol, propylene glycol and dioxane.

9. The plant growth stimulator of claim 2, wherein the polar organic solvent has one or more functional groups.

10. The plant growth stimulator of claim 2, wherein said polar organic solvent is acetone.

11. A method for stimulating plant growth which com-prises applying to the plants an effective plant growth stimula-ting amount of the plant growth stimulator of claim 1.

12. A method as defined in claim 11, wherein said concentrate comprises a mixture of one part by weight of 1-triacontanol with up to about 5,000 parts by volume of the polar organic solvent.

13. A method as defined in claim 11, wherein said concentrate comprises one part by weight of 1-triacontanol with up to about 1,000 parts by volume of the polar organic solvent.

14. A method as defined in claim 11, wherein the ratio of the concentrate to water is from 1:10,000 to 1:1 parts by volume.

15. A method as defined in claim 11, wherein the ratio of the concentrate to water is 1:1,000 to 1:100 parts by volume.

16. A method as defined in claim 11, wherein the polar organic solvent is selected from the group consisting of alcohols, ketones, water soluble ethers and glycols.

17. A method as defined in claim 11, wherein the solvent is selected from the group consisting of acetone, methyl ethyl ketone, methanol, isopropanol, diethylene glycol, n-butanol, propylene glycol and dioxane.

18. A method as defined in claim 11, wherein the solvent is acetone.

19. A method as defined in claim 11, wherein the 1-triacontanol is applied in an amount of at least 1 mg per acre.

20. A method as defined in claim 11, wherein the 1-triacontanol is applied in an amount of between 5 to 20 mg per acre.

21. A method according to claim 11, wherein said 1-triacontanol is dissolved in said polar organic solvent by heating said solvent and dissolving the 1-triacontanol in the heated solvent.

22. A method as defined in claim 11, wherein said plant is selected from the group consisting of sweet corn, field corn, sugar cane, tomatoes, cucumbers, and beans.

23. A method as defined in claim 11, wherein said plant is sweet corn.

24. A method as defined in claim 11, wherein said formulation is applied to the plants by spraying the formulation on to the growing plants.