# US 5,705,648 A · Mepiquat chloride

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- Number: US 5,705,648 A
- Document ID: US5705648A
- Status: Granted
- Kind: A
- Application number: 08/325,945
- Filed: 1994-10-17
- Granted: 1998-01-06
- Earliest claimed: 1992-06-04
- Assignees: Micro Flo Company
- Inventors: Richard U. Clark; James S. Lovell; James C. Thigpen; David William Bristol; John Raymond Tyndall; Albert Roger Frisbee
- Web page: https://patentgrep.com/patent/US5705648A

## CPC

- C07D 295/037: with quaternary ring nitrogen atoms
- A01G 7/00: Botany in general
- A01N 43/40: six-membered rings
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- A01G: HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING (picking of fruits, vegetables, hops or the like A01D46/00; propagating unicellular algae C12N1/12)
- A01N: PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF (preservation of food or foodstuff A23); BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES (preparations for medical, dental or toiletry purposes which kill or prevent the growth or proliferation of unwanted organisms A61K); PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS

## Abstract

Mepiquat chloride is formed from the reaction between N-methylpiperidine and chloromethane in an anhydrous liquid solvent selected from the group consisting of acetone, methyl ethyl ketone, toluene, tetrahydrofuran, isopropanol, acetonitrile, N,N-dimethylformamide and methylene chloride in the absence of sodium hydroxide. Mepiquat chloride precipitates as a solid of high purity and is recovered under a substantially moisture-free atmosphere. The solid mepiquat chloride can be sealed into a water soluble pouch or into a water soluble encapsulated solid form (e.g., granule, pellet, or briquette) for convenient handling. The pouch contains powdered mepiquat chloride or the encapsulated solid is merely introduced directly into a spray tank or reservoir for application with low human exposure and no containers in contact with the mepiquat chloride that require disposal. Mepiquat chloride is used as a component of a system for growing a number of commodity plants including cotton. The first component is a plant growth regulator applied. to at least one of: (a) a furrow for cotton plant seeds, (b) to a cotton plant bearing the first true leaves, (c) to a cotton plant at pinhead square, and (d) to a cotton plant at early bloom. The plant growth regulating agents produce higher plant masses with high levels of boll retention. At mid-bloom, mepiquat chloride is applied to retard vegetative growth in favor of fruit (boll) production.

## Claims

### Claim 1

A process for making mepiquat chloride comprising:
contacting chloromethane with N-methylpiperidine in an anhydrous liquid solvent selected from the group consisting of acetone, methyl ethyl ketone, toluene, tetrahydrofuran, isopropanol, acetonitrile, N,N-dimethylformamide and methylene chloride for a time sufficient to precipitate solid mepiquat chloride in a yield of at least 80%;
separating said solid mepiquat chloride from said solvent; and
recovering said solid mepiquat chloride.

### Claim 2 (depends on 1)

The process of claim 1 wherein the mepiquat chloride recovered exhibits a purity of at least 98 wt %.

### Claim 3 (depends on 1)

The process of claim 1 wherein said solvent is acetone or isopropanol.

### Claim 4 (depends on 1)

The process of claim 1 wherein chloromethane and N-methylpiperidine are contacted in said solvent in a molar ratio of chloromethane to N-methylpiperidine of at least 1:1.

### Claim 5 (depends on 1)

The process of claim 1 wherein the mepiquat chloride recovered has a purity of at least 99 wt %.

### Claim 6 (depends on 1)

A process as in claim 1 wherein the recovering step comprises:
recovering mepiquat chloride solids having a purity of at least 99.5 wt %.

### Claim 7 (depends on 6)

The process of claim 6 wherein said solvent is acetone.

### Claim 8 (depends on 1)

The process of claim 1 wherein the separating step and the recovering step are each conducted under an atmosphere substantially free of moisture.

### Claim 9

A process for making mepiquat chloride comprising:
contacting chloromethane with N-methylpiperidine in acetone for a time sufficient to precipitate solid mepiquat chloride in a yield of at least 80%;
separating said solid mepiquat chloride from said acetone;
recovering said solid mepiquat chloride; and
recycling said acetone.

### Claim 10 (depends on 9)

The process of claim 9 wherein the mepiquat chloride recovered exhibits a purity of at least 98 wt %.

### Claim 11 (depends on 9)

The process of claim 9 wherein said chloromethane is contacted with said N-methylpiperidine by bubbling chloromethane through N-methylpiperidine in acetone at a temperature of up to 70.degree. C.

### Claim 12 (depends on 9)

The process of claim 9 wherein the solid mepiquat chloride is separated from said acetone under an atmosphere consisting essentially of nitrogen.

### Claim 13 (depends on 1)

The process of claim 1 further comprising:
washing the separated solid mepiquat chloride with acetone, and
recovering the acetone used for washing said solid mepiquat chloride for recycle to the contacting step.

### Claim 14

Solid mepiquat chloride made by a process consisting essentially of:
contacting chloromethane with N-methylpiperidine in acetone in the absence of NaOH for a time sufficient to precipitate solid mepiquat chloride in a yield of at least 80%;
separating said solid mepiquat chloride from said acetone; and
recovering said solid mepiquat chloride solids exhibiting a purity of at least 99.5 wt %.

### Claim 15 (depends on 1)

A process according to claim 1 wherein greater than 90% of said N-methylpiperidine is converted into said mepiquat chloride.

### Claim 16 (depends on 1)

A process according to claim 1 wherein said contacting is performed at a temperature of about 70.degree. C. or less.

### Claim 17 (depends on 1)

A process according to claim 1 wherein said contacting is performed at a temperature within the range of 40.degree.-50.degree. C.

### Claim 18 (depends on 1)

A process according to claim 1 wherein said contacting is at a molar ratio of chloromethane to N-methylpiperidine of at least 1:1.

### Claim 19 (depends on 18)

A process according to claim 18 wherein said contacting is at a molar ratio of chloromethane to N-methylpiperidine within the range of about 1.05:1 to about 1.5:1.

### Claim 20 (depends on 1)

A process according to claim 1 wherein said separating and said recovering are conducted under an inert atmosphere.

### Claim 21 (depends on 20)

A process according to claim 20 further comprising:
sealing the separated mepiquat chloride in a package while under an inert atmosphere.

### Claim 22 (depends on 1)

A process according to claim 1 further comprising:
sealing the separated mepiquat chloride in a pouch made with a water soluble polymer.

### Claim 23 (depends on 22)

A process as in claim 22 wherein said water soluble polymer is selected from the group consisting of polyvinyl alcohol and cellulose-derived polymers.

### Claim 24 (depends on 23)

A process according to claim 23 wherein said pouch is enclosed in a foil outer pouch.

### Claim 25 (depends on 1)

A process according to claim 1 further comprising:
forming the separated mepiquat chloride into a solid pellet.

### Claim 26 (depends on 25)

A process according to claim 25 further comprising:
encapsulating said pellet with a water soluble outer coating.

### Claim 27 (depends on 26)

A process as in claim 26 wherein said water soluble outer coating is selected from the group consisting of polyvinyl alcohol and cellulose-derived polymers.

### Claim 28 (depends on 27)

A process as in claim 27 wherein said water soluble outer coating is selected from the group consisting of polyvinyl alcohol methyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, and mixtures thereof.