GB2053684A - Herbicide composition based upon bipyridilium salts containing a substance that imparts an unpleasant smell - Google Patents

Abstract

A liquid herbicide composition comprising a bipyridilium salt and, as a nauseating agent, from 0.025 to 0.1% by weight based on the weight of the total composition of tert. butylmercaptan and/or phenylmercaptan. The presence of the nauseating agent imparts an unpleasant odour to discourage human consumption of the composition, the odour remaining even on prolonged storage of two years.

Description

SPECIFICATION Herbicide composition based upon bipyridilium salts containing a substance that imparts an unpleasant smell The present invention relates to herbicide compositions comprising a bipyridilium salt and an agent suitable for imparting an unpleasant smell to the composition to make it nauseating and clearly recognizable as an undrinkable liquid.

It is known that those who often handle small quantities of herbicides to be used in orchards, market gardens or domestic gardens in general, often transfer the liquid compositions from their original container into bottles. Sometimes the bottles utilized are those which originally contained refreshing drinks and therefore there is a risk of causing dangerous poisonings by persons or children unwarily consuming the contents.

In order to avoid such a risk, it has become a common practice to add to the liquid herbicide bipyridilium salt compositions, a substance developing a nauseating odour that will discourage anybody from mistakably drinking the liquid herbicide compositions.

The choice of the substance imparting a nauseating odour is not so simple. For example, many such substances are not sufficiently soluble in water or in aqueous solutions of bipyridilium salts, with the resu It that they either precipitate on the bottom of the liquid composition or are situated on the surface of the liquid composition, and thereby are not evenly distributed throughout the composition, especially during decanting operations. Furthermore, the compounds must not react chemically with the formulation components and must be active on prolonged storage and not deteriorate.

United States Patent Specification No. 4075 005 discloses that good results are achieved when the bipyridilium salt compositions are additioned with alkyl-carboxylic acids such as balerianic or butyrric acids, in quantities from 0.5 to 5%. However it has been found that at pH values near neutrality, the nauseating smell tends to disappear.

British Patent Specification No. 1 406 881 discloses the addition of a pyridine base, e.g. a mixture of alkyl-pyridines, to the bipyridilium herbicide composition. However, the cost of such compounds is a drawback given that the basic pyridine varies depending on the origin, and it is necessary to carefully monitor the composition in order to be sure it meets the requested requisites.

The present invention has been made with the above points in mind.

According to the invention there is provided a liquid herbicide composition comprising a bipyridilium salt and, as a nauseating agent, from 0.025 to 0.1% by weight based on the weight ofthe total compositionoftert. butylmercaptan andlor phenylmercaptan.

It has been found that the presence of one or both of the two mercaptans imparts a nauseating odour to the bipyridilium herbicide compositions which persists even after prolonged storage for two years.

The mercaptans are preferably used at a concentration of 0.075% based on the weight of the composition and the composition preferably has a pH of from 3to8.

The advantages of such additives are the following: low cost of the agent capable of imparting the nauseating smell; small quantities of agent required for obtaining the desired effect (up to 25 times less than the quantities of alkylcarboxylic acids); a long persistence of the nauseating smell of the composition during storage; nauseating odour that will discourage anybody from drinking it.

The agent that imparts the nauseating smell proves to be compatible with the usual additives, surfactants, diluents used in the formulations of bipyridilium-based herbicides.

The pyridilium salt formulations, usually contain from 200 to 500 g/l of the active herbicide ingredient.

Under such conditions the formulations may be additioned with the indicated quantities of the mercaptans without deleterious effects.

The persistance of the nauseating smell is the same whether the product is kept at an acid pH or at alkaline pH values comprised within the values from 3 to 8. However, it is convenient to keep a pH value around 7.5 because the bipyridilium salts are not stable in an alkaline medium or environment.

The invention will now be illustrated by the following Examples.

Example 1 The following components were loaded into a homogenizer: 1,1' - dimethyl - 4,4' - bipyridilium chloride 250g water 7009 Under stirring the following components were then admixed: nonylphenyl-polyoxyethylate 209 quaternary derivative of cocoamine 309 silicon antifoaming agent 0.5g tert. butyl-mercaptan 0.5g.

The mixture was then made up to 1000 with water.

After complete dissolution, the formulation was poured into a closed bottle and stored at room temperature for two years. On opening the bottle after the storage period, the solution appeared clear and was giving off the characteristic unpleasant odour of tert. butylmercaptan.

Example2 1,1'-dimethyl-4A'-bipyridilium chloride 4009 water 5009 were loaded into a homogenizer and thereafter the following components were added under stirring: nonylphenyl polyoxyethylate 32g quaternary cocoamine derivative 489 silicon anti-foaming agent 0.59 phenylmercaptan lg.

The mixture was then made up to 1000 with addition of water, and the mixture was stirred until attaining complete homogenisation.

The formulation was then subdivided into two parts one part (500 9) was bottled as such, the other was diluted with 300 cc of water and then bottled.

After two years storage, when opened, both formulations were clear and emitted a nauseating smell.

Claims (10)

1. A liquid herbicide composition comprising a bipyridilium salt and, as a nauseating agent, from 0.025 to 0.1% by weight based on the weight of the total composition often. butylmercaptan andlor phenylmercaptan.

2. A liquid herbicide composition as claimed in Claim 1 which contains a total of 200 to 500 g/l of one or more bipyridilium salts.

3. A liquid herbicide composition as claimed in Claim 1 or Claim 2 in which the bipyridilium salt comprises the 1,1 '-dimethyl-4,4'-bipyridilium ion.

4. A liquid herbicide composition as claimed in any preceding claim in which the nauseating agent is phenylmercaptan.

5. A liquid herbicide composition as claimed in any one of Claims 1 to 3 in which the nauseating agent is tert.-butylmercaptan.

6. A liquid herbicide composition as claimed in any preceding claim in which the nauseating agent is present in an amount of 0.075% by weight based on the weight of the total composition.

7. A liquid herbicide composition as claimed in any preceding claim which additionally comprises one or more surfactants andlor diluents.

8. A liquid herbicide composition as claimed in any preceding claim which has a pH in the range 3 to 8.

9. A liquid herbicide composition as claimed in any preceding claim which has a pH of about 7.5.

10. A liquid herbicide composition as claimed in Claim 1 substantially as herein described with reference to either Example.