One kilogram of triflic acid is 0.59 litres. At a density of 1.6960 g/cm³, 1,000 g works out to 589.6 mL, and that number settles more about a small order than the assay does. The limited-quantity limit for UN 3265 by road, sea and inland waterway is 1 L per package, so a 1 kg bottle sits inside it. The air limited-quantity limit is 0.5 L — about 848 g — so the same bottle sits outside it by 90 mL, and flying it means fully regulated dangerous goods. "Send us one kilogram" is decided by the container and the transport mode long before purity comes up.
Disclaimer: This article is general practical information, not legal, customs or chemical-regulatory advice, and guarantees no classification, duty rate or regulatory determination for any transaction. Verify classification with a licensed customs broker (관세사), Korean chemical obligations with the competent authority, and dangerous-goods packing with the carrier and the exporting country's inspection body. Statutes, notices and safety data sheets change.
The Fab Does Not Buy This Acid
A memory fab rarely purchases triflic acid as a raw material. What arrives at the fab is photoresist, etchant and thin-film precursor, with the acid's trace inside them — a materials maker's input, and so a second-tier supply chain from the fab's point of view, invisible on its own bill of materials. The buyers are photoacid-generator and precursor synthesis houses, etchant and plating-bath formulators, and battery electrolyte makers, alongside pharmaceutical synthesis. The photoresist leg is documented in Korean regulation rather than in marketing material: Annex 2 of a notice of the National Institute of Chemical Safety (화학물질안전원) 「유해화학물질의 규정수량에 관한 규정」 names triphenylsulfonium trifluoromethanesulfonate (1:1), CAS 66003-78-9, and two further sulfonium and iodonium triflates as regulated substances in their own right — textbook photoacid generators carrying this acid's anion.
The precursor leg carries the purchasing arithmetic. In one granted Korean patent for a thin-film precursor, the acid converts the silane to a silyl triflate before the amine step, and the worked example charges it at about 1.1 equivalents to the silane. The category matters more than the ratio: the acid is a stoichiometric reagent here, not a catalyst, so consumption scales with precursor output rather than sitting flat at a catalytic loading. It is one worked example in one patent, with no yield given, so no conversion to acid per kilogram of precursor follows.
UN 3265 in Every Mode, and the 0.5 L Line in One of Them
The classification is uniform. Across US DOT, Canada TDG, ADR/RID, IMDG, ADN and IATA/ICAO the entry is the same — UN 3265, CORROSIVE LIQUID, ACIDIC, ORGANIC, N.O.S., Class 8, packing group II. No single safety data sheet we hold covers all six frameworks; two sheets for the acid between them do, and a third, for a 28% solution, overlaps four and agrees. Dilution does not help either: a 28% aqueous solution is also packing group II, so a weaker solution does not drop a grade and simplify the shipment.
The N.O.S. entry carries special provision 274, requiring the technical name alongside the proper shipping name. The document must read "Corrosive liquid, acidic, organic, n.o.s. (trifluoromethanesulfonic acid)"; one bearing only the generic description is incomplete — rejected at a counter rather than a chemistry problem. Under ADR the entry takes classification code C3, Kemler number 80, tunnel restriction code (E) and packing instruction P001; per an independent ADR reference, carriage in bulk is not permitted.
Then the thresholds, against the one litre that a kilogram is not:
Read the last row as a packaging instruction, not a freight detail: for air, the limited-quantity unit is 500 g, not 1 kg. One further rule constrains what a 1 kg pack can physically be — glass inner packagings require sufficient inert cushioning material in contact with inner and outer packagings, unless the outer packaging is a close-fitting moulded plastic box compatible with the substance.
What Producers Actually Publish About Packaging
The smallest unit any producer puts in public is a 25 kg stainless steel drum — 14.7 L at this density — against the 50 kg that circulates as the producer minimum. Japanese producers are the written reference in several of the lines we work in, as our Japanese materials landscape maps; the point here is narrower. The same family's lithium salt, a solid, is catalogued by a producer at 1 kg: one kilogram is an ordinary unit for the salt and not for the acid, and the difference is not purity but phase and dangerous-goods class.
One kilogram does exist in reagent distribution: a UK distributor publishes 50 g, 100 g, 500 g and 1 kg at 99.0% assay, with stock shown. Another publishes the container itself for a 10 g pack, in words — a 15 mL amber glass bottle, 28 mm neck, with a 28 mm blue cap containing a PTFE wad. Read that list again: the only fluoropolymer anywhere in the pack is the cap liner. The glass is the containment; the PTFE is a seal.
A 28 mm screw neck implies a bottle you open and pour, with no valve and no dip tube. Published sources stop at the neck and the cap, so we do not state that as established — but the gap it creates can be. A glass bottle with a screw closure has no place on a line that pressure-feeds from a closed connection, so a buyer whose process expects nitrogen push-out supplies the transfer arrangement itself, and should establish it before the order. We found no public catalogue offering a 1 kg stainless steel or PFA container for this acid; the 1-to-20 kg PFA or 316L specification that circulates for semiconductor use has no published source behind it.
China's Packing Certificate Is Two Documents, Not One
The export packing certification (危包证) is routinely discussed as a single permit obtainable above some order size. The size part is wrong: the customs administration's own guidance specifies no minimum quantity, and we found no quantity threshold anywhere in the regime. The constraint is structural instead, and the statutory basis shows why — Article 17 of the Import and Export Commodity Inspection Law and Article 29 of its Implementing Regulation split the duty between two parties: the container manufacturer applies for a performance appraisal of the container, and the producer of the exported dangerous goods applies for a use appraisal of it. Goods in containers never appraised, or that failed, may not be exported.
The validity periods come from Chinese industry commentary rather than statutory text; we did not obtain the governing measure, so treat the month figures as the shape of the problem, not as law.
Three consequences follow, and together they explain small-pack difficulty better than any quantity threshold would. The performance certificate is not yours, and not even your supplier's — it belongs to whoever made the container, and that maker must hold the export packaging production registration, so a request for a new bottle format reaches a third company. Two validity windows have to overlap: Class 8 puts the use appraisal at six months inside a container window of twelve, so repeat small orders keep reopening that overlap instead of amortising it. Repacking moves the certificates — fill small bottles at a trader or repacker and both documents are issued against that repacker's containers, so the document chain no longer runs back to the original producer's lot. That is the structural reason a small-pack certificate of analysis may not connect to the batch that made the acid; whether it does is a question to ask by name, alongside the manufacturer-versus-trader questions in our supplier due diligence checklist.
Korea Deleted the Category This Acid Is Still Filed Under
Some Korean reagent listings and Korean-language editions of foreign safety data sheets we have seen still mark this acid 「유독물질」 ("toxic substance"). That category no longer exists. The amended Chemical Substances Control Act effective 7 August 2025 deleted it and redistributed its contents by hazard type into 인체급성유해성물질, 인체만성유해성물질 and 생태유해성물질 — the same change we set out for gases in our specialty gas import guide.
Triflic acid is now an 인체급성유해성물질, an acutely human-hazardous substance, unique number 97-1-314, CAS 1493-13-6 — and the designating authority moved with it, the current designation notice taking its authority from the Act on Registration and Evaluation of Chemical Substances (K-REACH, 화평법) rather than from the Chemical Substances Control Act where buyers look for it.
The content threshold changed, and for a mixture that single figure decides whether the regime applies at all. The superseded designation notice (화학물질안전원고시 제2025-2호, in force 25 April 2025) read: triflic acid [1493-13-6] and mixtures containing it at 1% or more. The current quantity notice (제2026-4호, in force 6 May 2026) carries a content-threshold column, and against the same unique number it reads 10 — the threshold moved from 1% to 10% while the substance number stayed put. A good deal of secondary material still prints 1%.
The same annex now sets three quantity tiers where an earlier version of the quantity regulation (환경부고시 제2024-77호, April 2024) ran two and gave this substance 20 t with no upper figure at all: the 20 t tier is unchanged, with a 0.4 t tier added beneath it and a 250 t ceiling above.
The carry-over is explicit, and for this acid there is no transition to track. The first designation notice under the new system (화학물질안전원고시 제2025-19호, in force 7 August 2025) deems every substance designated as a 유독물질 under the former notice to be designated as an 인체등유해성물질 (Supplementary Provisions, Article 2), and treats a 화학물질 확인 submission or an import filing (수입신고) already made for the 유독물질 as made for the new category (Article 3(3)). Its grace periods — running to 1 July 2026, 1 January 2027, 1 January 2028 and 1 January 2030 — attach only to substances newly designated, including those whose content threshold was lowered. Triflic acid's threshold moved the other way, from 1% to 10%, so an importer already filed stays filed, and a mixture between 1% and 10% has left the regime. We read the supplementary provisions of the notices, not the amended Acts themselves. One thing this acid is not: an accident-preparedness substance (사고대비물질) — neither the current designation notice for those (제2026-2호, in force 10 March 2026) nor Annex 3 of the quantity notice contains CAS 1493-13-6 or the word 트리플릭.
And the family is not regulated as a family:
The anhydride is caught at half the content threshold and half the bottom tier; the lithium salt is not listed at all. A bundled quotation across the family — which is how this channel sells, the salts and the anhydride all descending from the acid — therefore carries four different regulatory answers. Price them together; clear them one at a time.
A Basket Tariff Line With Exactly One Korean Code
The heading is 2904.99, and in one jurisdiction it is written into the statute by name: US tariff subheading 9902.02.06 reads "Triflic acid (trifluoromethanesulfonic acid) (CAS No. 1493-13-6) (provided for in subheading 2904.99.50)," with 9902.02.07 doing the same for the anhydride. Chapter 99 subheadings are temporary duty-suspension provisions, so the cross-reference to 2904.99.50 is what we rely on, not any rate inside them. The exclusion logic closes on the heading texts alone — 2904.10 covers derivatives containing only sulpho groups, and this molecule carries sulpho and fluorine, so it falls to 2904.99, "Other."
In Korea that residual heading has exactly one ten-digit line, 2904990000, whose standard commodity name list has a single entry: "Other." The required specification field "Type" offers two values — 01 for 2,4-dinitrochlorobenzene and p-nitrochlorobenzene, and 02 for "Other" — so declaring this acid means writing 02, Other, no standard name existing for it. That is sharper than the usual complaint about basket headings: the problem is not that statistics aggregate the acid away after the fact, but that the declaration itself never distinguishes it. Any average unit value from that line averages unrelated chemicals, so it cannot sanity-check a quotation.
For the 2026 calendar year the line carries a base rate of 8% and a WTO concession rate of 5.5%, and the Korea–China FTA column reads 0%. The hedge on that last figure is real: the preferential rate-kind codes are not named in the published code table we worked from, and we read them by convention. Preference also turns on origin documentation and on the ten-digit line being settled for the article actually imported. Fix the line by advance ruling (관세법 제86조 품목분류 사전심사) as our sputtering target guide describes, and have a broker confirm the preference before pricing it in. No anti-dumping or countervailing measure is recorded against the line.
"99.5%" Tells You Almost Nothing
Published commercial specifications live between 98% and 99.5% — a UK distributor at 99.0%, a large US reagent house with both a 98% grade and a ≥99% grade, Chinese supplier pages commonly at 99% — and the number by itself separates almost nothing.
Industry-practice basis. Actual requirements are set by the customer specification and must be confirmed against it, not against this table.
The cell marked "no published specification" is not an omission. We could not find a metals limit for this acid published by any producer, anywhere. One producer states that it offers a high-purity grade and publishes no numbers for it; the only numeric impurity panel we located sits on a Chinese supplier's own sales page, a single source selling the product, so we print none of it. Our own triflic acid page says the same from the other side — there is no single industry-standard impurity table for this acid, so the metals panel is agreed per order — and this research confirmed that sentence rather than qualifying it.
So the metals panel is something the buyer writes. If the purchase order does not name the elements, the limits and the analytical method, the certificate of analysis comes back with assay, water, sulfate and fluoride — all real, none answering the question an electronic-materials buyer is asking. The rest of that discipline, production lot and method on the COA, is in our sample evaluation protocol.
Storage: the Safety Data Sheets Disagree
Published safety data sheets for the same CAS number do not agree on how to store it. One instructs "Keep refrigerated. (Store below 4 °C / 39 °F)" with a nitrogen blanket. A second says cool, dry, well ventilated, hygroscopic, and "store under argon." A distributor's product data gives +20 °C and shipping at ambient. Both the temperature and the inert gas differ by source. Take the storage clause from the supplier's own safety data sheet for the lot you are buying, and settle it before the drum arrives.
Materials of construction are clearer, and one-sided. A safety data sheet states plainly: do not use aluminium or galvanised containers, and the acid "reacts with mild steel, galvanised steel / zinc producing hydrogen gas which may form an explosive mixture with air." Note what it does not say. It does not clear stainless steel. Mild steel and 316L are different materials, and no safety data sheet we read states a stainless compatibility either way — so get that in writing from the supplier.
The GHS classifications split on the fine subdivision too — skin corrosion 1B on the two sheets that classify under GHS, category 1 or 1A behind the Korean quantity tiers, metal corrosivity on one sheet only — so use the behaviour rather than a subdivision: skin corrosion and serious eye damage, hydrogen evolution against mild steel, and decomposition products including carbon monoxide, oxides of sulphur and hydrogen fluoride. It boils at 162 °C, freezes at −40 °C, and is a superacid stronger than sulfuric; the Hammett figure widely quoted for it we could not trace to an original measurement, so no number appears here.
What We Could Not Establish
- Market size. Published estimates for the same base year differ between research houses by more than a factor of three. Product definition — pure acid, solutions, or the family together — and regional scope appear to vary, which we could not confirm either, having obtained no report text or methodology. No market figure appears above, and no price forecast: we have no sourced basis for one.
- Electronic-grade impurity limits. No producer anywhere publishes a metals specification for this acid — the finding most likely to change how an order is written. What any particular buyer requires is equally closed; those limits live in purchase orders only.
- Small-pack hardware. No public catalogue for a 1 kg stainless or PFA container, and the absence of a valve and dip tube on 1 kg bottles rests on supplier correspondence rather than a published source.
- Looked for and not found. Any support for the claim that this acid is a stoichiometric input to diiodosilane, the SiN atomic-layer-deposition precursor. The published routes we read use iodine, magnesium iodide or iodide halide exchange instead, so a consumption estimate built on that route has nothing under it.
- Primary texts beyond the notices. The Chinese certificate validity periods in statutory form, and whether the six-month content–container compatibility test report some commentary attaches to the use appraisal is real — it is not in the customs administration's guidance. ADR Part 4 packing instruction P001 in full, the UNECE download and a mirror both returning 403, so the glass-inner-packaging mass limit in secondary summaries stays unverified — well above a kilogram in any case. The amended Chemical Substances Control Act itself, as against its subordinate notices. And no K-REACH existing-substance number from a primary source, so none is printed, nor the claim-level patent count that circulates for Korean filings mentioning this acid.
Before the First Order
- Decide the transport mode first. Air caps a limited-quantity package at 0.5 L, about 848 g; a 1 kg bottle flies only as fully regulated dangerous goods.
- Name the container in the enquiry — glass, stainless or fluoropolymer; valve and dip tube or open pour; neck size against the receiving connection. Ask for a photograph of the mouth.
- Check the transport document carries the technical name after the n.o.s. entry, per special provision 274.
- Ask for the Chinese packing certification as two documents, compare the remaining validity of each, and ask whether the container maker holds the export dangerous-goods packaging production registration — the long pole where a new bottle format is proposed.
- Exclude aluminium, galvanised steel and mild steel, get stainless or fluoropolymer compatibility confirmed in writing, and take the storage clause from the lot's own safety data sheet.
- Write the metals panel into the purchase order — elements, limits, analytical method — and ask who filled the bottle and whether the COA carries the original production lot number.
- Clear the family item by item, using the current Korean designation: 인체급성유해성물질, number 97-1-314, content threshold 10%, not an accident-preparedness substance — and an importer's existing 유독물질 filing carries over automatically. And fix the ten-digit tariff line by advance ruling before any preferential rate is priced in.
Frequently Asked Questions
Can we air-freight 1 kg of triflic acid as a limited quantity?
No. The IATA limited-quantity packing instruction for UN 3265 packing group II, Y840, caps a package at 0.5 L — about 848 g at this acid's density — and 1 kg is 0.5896 L. The kilogram clears the 1 L road, sea and inland-waterway limit comfortably and misses the air limit by 0.09 L, so flown it travels as fully regulated dangerous goods under PI 851. For limited-quantity carriage by air the package has to come down to 0.5 L — 848 g — which in catalogue terms means the 500 g pack.
Is triflic acid a 「유독물질」 in Korea?
That category was deleted. As amended effective 7 August 2025, the Chemical Substances Control Act redistributed 유독물질 into three hazard-based categories, and this acid is now an 인체급성유해성물질, unique number 97-1-314. Two changes matter commercially: the designation runs off the Act on Registration and Evaluation of Chemical Substances (K-REACH) instead, and the content threshold for mixtures moved from 1% to 10%. It is not an accident-preparedness substance, an importer's existing 유독물질 filing carries over automatically, and anything still citing 「유독물질」 or a 1% threshold predates the change.
What purity should we specify for semiconductor use?
Purity is the easy part: commercial material sits between 98% and 99.5%, so the assay separates very little. Fitness is decided by the metals panel, and there is no published industry specification for it from any producer we could find. So the buyer writes it — elements, limit for each and analytical method in the purchase order, with the certificate of analysis reporting against them on the production lot.
Does the China packing certification only need to come from one party?
No. It splits across two parties and two documents — the container manufacturer holds the performance certificate, and the dangerous-goods producer or exporter holds the use appraisal that depends on it. Their validity windows differ (a twelve-month container window against a shorter use-appraisal window for Class 8) and have to overlap, and repacking at a trader moves both certificates to the repacker's containers, which can break the paper trail back to the original producer's lot. Ask for both documents by name, not just "the packing certificate," and ask whose containers they were issued against.
References (Public Sources)
Held in full and read directly: safety data sheets from three non-Chinese suppliers, one for a 28% aqueous solution; a notice of the National Institute of Chemical Safety 「유해화학물질의 규정수량에 관한 규정」 (in force 6 May 2026), Annexes 1 to 3; the superseded 「유독물질의 지정고시」 (25 April 2025) with its 1% entry and transitional provisions, and an earlier version of the quantity regulation it worked with (11 April 2024); the enabling provision of the current 인체급성유해성물질 designation notice; the 「사고대비물질의 지정」 notice (10 March 2026); Korea Customs' 2026 HS code, duty-rate and standard-commodity-name datasets; and US tariff subheadings 9902.02.06, 9902.02.07 and 2904.99.50.
Read partially or through secondary sources: UN Model Regulations special provision 274 and the ADR, IMDG and ICAO–IATA entries for UN 3265, from supplier safety data sheets cross-checked against an independent ADR reference; China's Import and Export Commodity Inspection Law Article 17 with Article 29 of its Implementing Regulation, plus customs guidance on export packaging inspection and industry commentary for the validity periods; producer and distributor product pages; one granted Korean patent for the aminosilane route and five further patents for iodosilane routes.
Prices, market estimates, impurity panels and company names are absent above because the public record does not carry them in a form we were willing to print.
Nami Tech Solutions (NTS) lists this acid as a catalogue line and handles the dangerous-goods work that comes with it. The small-pack route we do not claim as settled — the sections above explain why not. What we can do before an order exists is the written part: fixing the container specification and the transfer arrangement, drafting the metals panel and COA fields into the specification instead of leaving them to a standard certificate, and putting the packing certification and transport documents in order for the mode being shipped.
