chemistry

Tri-allate

Tri-allate is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tri-allate rather than just read about it. In short: Tri-allate or triallate is a selective pre-emergent thiocarbamate herbicide, used to control wild oats and sundry grasses and broadleaf weeds, often co-applied with trifluralin, which is much weaker against wild oats than tri-allate. Residual control can be expected for 6 to 8 weeks.

Key takeaways

Tri-allate belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tri-allate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tri-allate from memory before moving on to harder problems.

Reference excerpt

Tri-allate or triallate is a selective pre-emergent thiocarbamate herbicide, used to control wild oats and sundry grasses and broadleaf weeds, often co-applied with trifluralin, which is much weaker against wild oats than tri-allate. Residual control can be expected for 6 to 8 weeks. It is used in Australia, India and the United States. It was first registered in 1961. In 2001, US agriculture used 2.3 million pounds (1,000 t) annually. Tri-allate is a mitosis-inhibitor; its HRAC classification is Group J (Aus), Group K3 (global), Group 15 (numeric). Affected weeds are prevented from germinating, or their shoots will be swollen and bright green.

Environmental behaviour Under very dry conditions, tri-allate can persist in soil for several months, and can damage field oats and sorghum. Degradation is dependent on soil microörganisms and moisture levels. Tri-allate is nontoxic to birds and bees, though it is very toxic to aquatic life. It doesn't bioaccumulate in plants, and has low mobility in soil. The aquatic toxicity is most potent against invertebrates and algae. The EPA says "the overall ecological risk associated with the use of triallate is low". The average soil half life is 82 days in "typical" conditions; it is also measured at 46 days, under "field" conditions. Similar half-life is seen in water sediment and in acidic (pH 9) solution.

Properties Triallate is synthesised from diisopropylamine, phosgene and 2,3,4-trichloro-phenyl-1-thiol. Its surface tension is 0.049 N/m, as a 90% solution at 20 °C. Monsanto manufactured it in the 1960s by the reaction of diisopropylthiocarbamate salt with 1,1,1,3-tetrachloro-propene. It is soluble in acetone, ether, ethyl alcohol, heptane, benzene, ethyl acetate and most organic solvents. Diallate is almost identical, but missing one of triallate's 3 chlorine atoms. Unlike triallate, it has cis- and trans- isomers.

Health Exposure to large amounts of tri-allate may harm the liver, spleen and kidneys. The EPA considers tri-allate to be a possible carcinogen, the result being "borderline" statistically significant in a trial on mice, though their rough estimate is that the chance of cancer from dietary triallate is one in 14 million. This trial only showed an increased incidence of tumors in one measured category, in a sample size of 15. Diallate, a very similar herbicide, was carcinogenic, possibly prompting the concern for triallate. In tests on rabbits, no fetotoxic or teratogenic effects were observed, although a small decrease of birth weight was strongly evidenced.

Regulatory status Tri-allate is limited to the US states of California, Colorado, Idaho, Kansas, Minnesota, Montana, Nebraska, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming, as of 2023. In Australia, all states allow it to control wild oats and most allow its broader use in combination with trifluralin. It is used in the United Kingdom, Morocco and the EU states of Belgium, France, Ireland and the Netherlands.

Application It is incorporated to soil pre-sowing or (IBS) incorporated by sowing, and is applied immediately before or up to 3 weeks before sowing. It is recommended to incorporate it 2–4 cm deep, and within 6 hours if the soil is moist, or 24 hours if dry, to minimise volatilisation. Proper incorporation is essential for efficacy, and two-pass incorporation is needed for maximum efficacy. Efficacy can also be reduced if the top 2 cm of soil is very dry. Tri-allate is applied at 0.8-1.0 kg/Ha (0.71-0.89 lbs/ac) in Australia, with a spraywater volume of 30 to 100 L/Ha (3.2-10.7 US gal/ac). Triallate is sold as an emulsifiable concentrate of 500 g/L active ingredient.

Compatibility Tri-allate is compatible with spray mixes containing chlorsulfuron, diclofop-methyl, trifluralin, glyphosate and oryzalin.

Crops applied to Tri-allate is applied to wheat, triticale, chickpeas, barley, peas, linseed, lupins, canola, faba beans and safflower. It was used on canary grass, but this registration was not renewed by the manufacturers, circa 2000.

Weeds controlled Tri-allate is used to control wild oats, annual ryegrass, wireweed, phalaris spp, fumitory, cereal oats, sand fescue, silvergrass, wintergrass, paradoxa grass (canary grass), corn gromwell (sheepweed) and rough poppy. It suppresses brome grass, barleygrass, cornered jack (doublegee), caltrop (yellowvine & bullhead), yellow burr weed, deadnettle and speedwell.

Tradenames Triallate has been sold as Avadex, Buckle, Far-Go, Showdown, Check Mate, Triallate Gold, Triallate and Tri-Allate.

References

Links Tri-allate in the Pesticide Properties DataBase (PPDB)

Illustrations

Worked examples

Example 1 — a first encounter with Tri-allate

Start with the simplest possible case. Write down what Tri-allate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tri-allate before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tri-allate ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tri-allate

In research: Tri-allate appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tri-allate in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tri-allate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Diisopropylamino compounds, Group 15 herbicides, Group 8 herbicides, so understanding it makes those chapters shorter.
In everyday life: Look for Tri-allate outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Tri-allate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tri-allate means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tri-allate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tri-allate in simple terms?

Why does Tri-allate matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tri-allate?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tri-allate.