1,3-Dichloropropene Technical Grade: How to Read a COA (Purity, Cis/Trans and the 1,2-Dichloropropane Impurity)

1. Identify the chemical by CAS number, not by abbreviation

In trade correspondence “1,3-D”, “DCP” and “dichloropropene” are used loosely, and similar names are easily confused. Put the full name and CAS number on every specification, sample request and purchase order.

Sources: California DPR · WHO/IPCS EHC 146 · NIST

A practical tip: if a supplier’s English documents write “dichloropropane” where they mean “dichloropropene”, ask for a correction before you sign. One letter changes the substance, and customs, shipping and registration documents all depend on it.

2. What “purity” means for technical 1,3-D

There is no single purity standard shared by all commercial products. Some published reference points:

Sources: EPA Telone II label · ATSDR ch. 3 · ATSDR ch. 5 · Sigma-Aldrich · TCI

The University of Hertfordshire Pesticide Properties Database, summarizing the EU review dossier, gives a minimum active-substance purity of 970 g/kg (97%) for the material assessed in the EU (PPDB). That is a reference point for one dossier, not a worldwide legal minimum — your own requirement depends on your registration, formulation or synthesis route.

For every offer, settle three questions:

• What is counted? “Total 1,3-D” should mean cis + trans. A trans-only figure is a different measurement.
• On what basis? Weight percent of the product as supplied, or normalized GC area percent? These are not the same, especially when water and other components are present.
• By what method? Ask for the method reference and how peaks were identified. A chromatogram peak does not name itself.

Do not calculate kilograms of active ingredient from an unexplained GC area percentage. First agree how the assay relates to the mass of product you will receive.

3. A COA checklist to use before you approve a sample

4. The impurity that deserves its own line: 1,2-dichloropropane

1,3-D and 1,2-dichloropropane (1,2-DCP) come from the same industrial chemistry: both are by-products of chlorinating propylene to make allyl chloride. That is why historical “DD” soil fumigants were roughly half 1,3-D and about a quarter or more 1,2-DCP (ATSDR). Modern technical 1,3-D is far more refined, but some 1,2-DCP can still carry through distillation.

Why 0.1% is the threshold that matters

1,2-Dichloropropane has a harmonised EU classification as a Category 1B carcinogen (EU-OSHA Roadmap on Carcinogens). Under the EU CLP rules, a mixture containing 0.1% or more of a Category 1B carcinogen must itself carry H350 “May cause cancer”. 1,3-Dichloropropene on its own is classified as a suspected carcinogen, H351 (ICSC 0995). In other words, the 1,2-DCP content can change the hazard statement on the drum label and the SDS — and with it the importer’s labelling, workplace and registration obligations.

Registration dossiers can go further. The PPDB summary of the EU dossier lists 1,2-dichloropropane as a relevant impurity at 0.1 g/kg (PPDB) — a relevant impurity being one that needs its own specified maximum because of its toxicological or environmental significance.

What this means when you buy:

• Always write a 1,2-DCP maximum into your specification. Total purity does not control it: two products with the same total assay can contain very different amounts of 1,2-DCP.
• Match the limit to your use. A registration holder or formulator should take the limit from the registration file; a synthesis buyer may accept a higher level.
• Expect low-impurity grades to cost more. Pushing 1,2-DCP to very low levels takes extra distillation and lowers yield.

5. Stabilizers: ask whether one was added

Some commercial 1,3-D products have been stabilized — ATSDR describes Telone II versions with about 1% epichlorohydrin or 2% epoxidized soybean oil (ATSDR). A stabilizer lowers the main assay figure, may need to be declared in your registration and SDS, and affects compatibility with your formulation. Ask whether the material is unstabilized, and if not, what was added and how much.

6. Does more trans mean better nematode control?

Not by itself. An isomer assay describes composition; it does not prove field performance. An EPA technical document from 2008 describes the cis (Z) isomer as the more nematicidally active one, so an unconditional “high-trans is better” claim needs evidence behind it (EPA, 2008).

High-trans material makes sense when a synthesis route needs that isomer. For fumigant use, what matters is whether the composition fits your approved product and whether efficacy data exist for your crop and soil. Soil conditions matter too: in one study in sandy loam at 20 °C both isomers had a half-life of 6.3 days, falling to 1.8–1.9 days when 5% composted manure was added (Dungan et al., 2001). A purity number cannot predict that.

7. Packaging, materials and dangerous-goods transport

1,3-D is transported as UN 2047, dichloropropenes, Class 3, Packing Group III, and is a marine pollutant. Its GHS classification includes flammable liquid, acute toxicity, carcinogenicity and very toxic to aquatic life with long-lasting effects (ICSC 0995). Check the SDS of the exact grade for the full classification.

• UN-specification packaging. Drums or IBCs for sea freight must carry a valid UN packaging mark suitable for Class 3, PG III liquids. Ask for the mark and the test report.
• Materials. The Telone II label warns against containers, pumps or transfer equipment made of aluminium, magnesium or their alloys, because 1,3-D can be severely corrosive to them under certain conditions (EPA label). Check that drum material, liner and gaskets are rated for chlorinated hydrocarbons.
• Volume vs. net weight. “200 L drum” is a capacity, not a weight. 1,3-D is denser than water and drums are filled with headspace, so agree the net kilograms per package in the quotation.
• ISO tanks for volume. For full-tank quantities an ISO tank removes drum cost and handling — it is how we prefer to ship bulk orders.

8. Import rules: shipping documents are not market authorization

A commercial invoice, SDS and COA do different jobs. Having all three does not mean a pesticide may be imported, sold or applied in your country.

• United States. EPA states that imported pesticides must meet registration, labeling and producing-establishment requirements, and importers file a Notice of Arrival; an establishment number is not a product registration number (EPA). California adds its own 1,3-D rules — DPR’s occupational and bystander regulations took effect on 1 January 2026 (CDPR).
• European Union. Commission Implementing Regulation (EU) 2022/740 of 13 May 2022 did not approve 1,3-dichloropropene as a plant-protection active substance; EFSA could not finalise the consumer, operator and resident risk assessment and identified possible groundwater concerns (EUR-Lex). REACH registration is not plant-protection approval, and any emergency authorization needs its own current, country-specific evidence.
• Other markets. Tell your supplier the country, the intended use and the importer of record, and confirm local registration or permit, label language and dangerous-goods acceptance at the port. Approval in one country is not approval in another.

9. Comparing quotations fairly

Compare prices only after the specification is aligned. For a verified weight-percent assay:

For example, one metric ton at 92% w/w contains 920 kg of 1,3-D; at 97% w/w it contains 970 kg — about a 5% difference in active content before any impurity or regulatory differences are counted. This does not apply to unexplained GC area figures.

Then compare commercial terms: currency, net weight, packaging, loading port, Incoterm, freight, insurance, inspection, validity and lead time. A low ex-works price is not a landed cost.

10. What we supply, and how to get a fast, useful quote

Zibo Yixiao is the export arm for 1,3-dichloropropene produced by Shandong Haiyi Chemical Technology Co., Ltd. in Zhanhua District, Binzhou, Shandong. We also supply 1,2-dichloropropane (CAS 78-87-5).

To get a quotation you can act on, send us:

1. Intended use (formulation, registered product, synthesis or laboratory evaluation)
2. Grade, and your limits for total 1,3-D, cis/trans and 1,2-DCP
3. Quantity: sample, first order, expected yearly volume
4. Destination country and port, plus your importer or registration-holder requirements
5. Documents you need (COA, SDS, others)
6. Packaging and Incoterm

Frequently asked questions

Author: Qi Wenlong, Export Sales, Zibo Yixiao. Sources checked November 2026. Your acceptance limits, product authorization and shipping arrangements must be set for each transaction. TELONE is a third-party trademark, mentioned only to identify public source documents; we claim no affiliation or equivalence.