A cargo of epichlorohydrin (ECH, CAS 106-89-8) is a colourless liquid, but its transaction value is not a physical constant. A buyer who stores a spot quote as a permanent number is anchoring capital to a figure that expires with the next feedstock settlement, energy price change, freight adjustment, or moisture specification deviation. The proper treatment of epichlorohydrin price per ton is therefore not a single printed value but a cost model: an indexed arithmetic structure that can be recalculated when route yields, caustic credits, logistics, and quality limits move.

Epichlorohydrin Price Per Ton: A Cost Model Instead of a Number That Expires

A spot number without supporting basis has no audit path. A price assessment published as CFR China is not interchangeable with an FOB USG railcar quote; the difference includes ocean freight, terminal storage, tank container positioning, local environmental compliance, and demurrage risk. The modelled cost per tonne of ECH can be written as the sum of route-specific feedstock consumption multiplied by dated contract prices, divided by plant yield, plus energy, fixed charge, logistics, and minus coproduct credit. Each input must carry a unit, a date, and an assay basis. Without that matrix, a buyer is comparing a current cargo against a historical opinion, not a deliverable material.

In practice, a published spot assessment is already an aggregation of multiple model inputs that were assumed weeks before publication. The quoted value persists after the energy index has changed. This is why procurement groups that track only the spot history accumulate error faster than those that maintain a live cost model with indexed inputs and settlement-language triggers.

Why Does a Spot Price Accumulate Error Before the Vessel Sails?

ECH production economics begin with either the propylene-based allyl chloride route or the glycerin-to-dichloropropanol route. Both routes consume caustic soda or an equivalent base during saponification, and both generate sodium chloride or related chloride-containing streams. The chlor-alkali balance is not static: caustic soda value moves inversely with chlorine demand, and an ECH plant that is not integrated with a chlor-alkali unit must purchase chlorine or hydrochloric acid while managing coproduct caustic economics. A published spot price made during a chlorine shortage will not hold after the chlorine contract resets.

Fuel and power are also priced inputs. Steam is required for distillation; electricity is required for chlorine compression, vacuum systems, and wastewater treatment. In an integrated plant, energy contracts settle quarterly or monthly. If a buyer treats a spot ECH quote as a stable transfer price, the error is transferred into the budget forecast as soon as natural gas or power deviates from the model assumption. The same applies to shipping: ECH is moved in lined steel or stainless steel containers, railcars, or barges. The flash point of roughly 31 °C by closed-cup ASTM D93 forces heated storage and handling controls, and freight cost is not a flat markup per tonne.

Feedstock, Coproduct, and Energy Terms in the ECH Cost Equation

Propylene-based production proceeds from propylene and chlorine to allyl chloride, then via chlorohydration to dichloropropanol, and finally to ECH by caustic saponification. The glycerin route replaces propylene with purified or crude glycerin and consumes hydrogen chloride before the same saponification step. The two routes do not share specific consumption coefficients. A common error in cost modelling is to apply a propylene-route mass balance to a glycerin-route plant; the resulting number is structurally invalid because the feedstock coefficient, coproduct chloride load, and energy profile differ. Published data for exact licensor-specific mass balances is limited because supplier agreements hold these balances confidential, but plant-level models can be built from quarterly yield tests, supplier certificates, and energy metering.

In a glycerin-route plant, crude glycerin is not a uniform feedstock. It enters from biodiesel producers with variable methanol, water, ash, and matter organic non-glycerol. A receiving plant must operate acidulation, evaporation, and thin-film distillation before chlorination, and the salt generated in caustic saponification creates a solid-liquid separation burden. Centrifugal separators exposed to chloride-containing slurry require corrosion-resistant alloys. If the receiving plant buys crude glycerin on a high-ash basis, the upstream purification cost must be added to the model; otherwise the apparent feedstock saving disappears into downstream maintenance and waste handling. A cost model should therefore purchase glycerin on an assay-adjusted price, not on a generic per-ton index.

For the propylene route, the model must include propylene contract settlement, chlorine, and caustic soda. Integration with a chlor-alkali complex can either reduce the net cost through coproduct credit or increase site complexity through chlorine logistics. ECH production consumes sodium hydroxide in the saponification reaction; the modelled cost must net out any saleable coproduct streams, but only if they meet specification and have a verifiable off-take. A coproduct credit that cannot be sold is not a credit.

If Water Content Is Not Controlled, the Price Per Ton Buys a Different Molecule

ECH reacts with water by epoxide ring opening to form 3-chloro-1,2-propanediol and can ultimately release hydrochloric acid. Moisture control is therefore part of the transaction price. A cargo that drifts above the agreed water limit is not marginally off-spec; it is a different material with a shorter stable shelf life, higher corrosion potential in unlined equipment, and greater risk to downstream reaction stoichiometry. Transaction specifications commonly require water ≤100 ppm by ASTM E203, assay ≥99.9 wt%, colour ≤10 APHA by ASTM D1209, and density near 1.18 g/cm³ at 20 °C by ASTM D4052. A producer shipping at 250 ppm water has not provided a small discount; it has transferred a storage and analytical liability to the buyer.

The moisture limit is not only a producer-side issue. A buyer using ECH in liquid epoxy resin synthesis must predry storage and maintain a nitrogen blanket. If a tank headspace is opened repeatedly under high-humidity conditions, atmospheric water ingress can degrade the assay before the material reaches the reactor. The price per tonne must therefore include the cost of dry storage, because excluding it creates an understated delivered cost.

In a DGEBA synthesis reactor, bisphenol A is dissolved in ECH, and sodium hydroxide is added gradually. The addition rate is limited by exotherm and by the formation of oligomeric fractions. On a production-scale batch reactor, loss of agitation or a cold jacket failure can produce local gelation at the agitator hub because ECH is both solvent and reactant. A batch loss is not reflected in the ECH invoice, but it is reflected in the conversion unit’s fixed-cost absorption. A cost model that stops at the plant gate misses this yield penalty.

Residual ECH in liquid epoxy resin is further reduced by vacuum stripping. Standard DGEBA epoxy resin has an epoxide equivalent weight near 188 g/eq; residual ECH acts as a monofunctional diluent and shifts hardener stoichiometry. Food-contact coating users must also verify compliance with FDA 21 CFR 175.300 and EU 10/2011. ECH is a reactive monomer and is not a permitted residual in food-contact polymer; analytical detection limits become a cost term for the supply chain. This is why two cargoes with the same per-ton spot price can have very different value depending on the end-use specification burden.

Epichlorohydrin rubber and polyamidoamine wet-strength resin production impose further quality demands. In epichlorohydrin rubber compounding, the polymer’s chlorine content influences vulcanization kinetics and metal adhesion. Mixing is performed in internal mixers or twin-screw extruders with high L/D ratios, and the scorch time is measured on a moving die rheometer at elevated temperature. A slight shift in ECH quality changes the cure response, and the rubber processor pays for it in scrap or rework. The per-ton price of ECH is therefore only the first entry in a batch record; the final cost depends on the analytical limits and the downstream process behaviour.