Diisopropanolamine CAS 110-97-4

What is Diisopropanolamine?

Diisopropanolamine is the secondary member of the isopropanolamine family — two hydroxypropyl arms on a single nitrogen, [CH₃CH(OH)CH₂]₂NH. It is the propylene oxide counterpart of diethanolamine, and the comparison between the two explains most of what it is used for.

The two methyl groups make it bulkier and more sterically hindered around the nitrogen than DEA, and that hindrance is the key to its most distinctive application. A hindered secondary amine forms a less stable carbamate with carbon dioxide, which slows carbon dioxide absorption while leaving hydrogen sulphide uptake — a simple proton transfer — unaffected. The result is selectivity: DIPA can pull hydrogen sulphide out of a gas stream while leaving much of the carbon dioxide behind.

Physically it is a white crystalline solid melting at about 42 °C, which puts it firmly in the heated-handling category. An 85% aqueous solution is widely traded for exactly that reason and is what most plants actually buy.

Commercially, DIPA's distinctive market is selective gas treating, where it also hydrolyses carbonyl sulphide — a contaminant that other amines struggle with. Beyond that it is used in cement grinding aids, metalworking fluids, surfactants and agrochemical salt formation.

Why diisopropanolamine specifically

• Selectivity for hydrogen sulphide. Steric hindrance destabilises the carbon dioxide carbamate without affecting hydrogen sulphide uptake, which allows selective sweetening where total removal is not wanted.
• Carbonyl sulphide hydrolysis. DIPA converts carbonyl sulphide to hydrogen sulphide and carbon dioxide, which it then absorbs — a genuine advantage over amines that simply degrade on contact with COS.
• Lower corrosivity than the ethanolamines. Gentler on carbon steel in hot service, which has real consequences for amine unit metallurgy and maintenance.
• Lower foaming than DEA. The methyl groups disrupt foam stabilisation, which matters in both gas absorbers and metalworking fluids.

How DIPA is Manufactured

Diisopropanolamine is made alongside MIPA and TIPA by reacting propylene oxide with ammonia. The reactant ratio decides which of the three dominates.

• Propoxylation of ammonia. Aqueous ammonia is reacted with propylene oxide. Each isopropanolamine formed competes with ammonia for the next molecule of propylene oxide, so all three form together in the same reactor.
• Ratio control. A plant configured for DIPA runs a lower ammonia-to-propylene-oxide ratio than one making MIPA, and recycles the mono product to push the equilibrium onward.
• Isomer distribution. Propylene oxide can open at either carbon, so a small proportion of positional isomers forms alongside the main product and appears on a detailed certificate.
• Separation and finishing. Ammonia is stripped and recycled, water removed, and the three isopropanolamines separated by vacuum distillation. The DIPA cut is then flaked, or dissolved to make the 85% solution that most buyers prefer.

Typical Commercial Specification

Figures below are representative of commercial flake grade. The 85% solution and gas-treating grades with tighter ionic limits are available — send us the specification you work to and we will quote against it.

Physical & Chemical Properties

Reactivity in practice

A hindered secondary amine with two secondary hydroxyls. The hindrance is what shapes its most valuable chemistry:

• Selective acid gas absorption. Takes up hydrogen sulphide rapidly by proton transfer while forming only a weak carbamate with carbon dioxide, giving genuine selectivity between the two.
• Carbonyl sulphide hydrolysis. Converts COS to hydrogen sulphide and carbon dioxide, which are then absorbed — removing a contaminant that degrades other amines rather than being removed by them.
• Salt and soap formation. Neutralises acids to give soluble salts, and fatty acids to give low-foaming soaps used in industrial fluids.
• Metal complexation. The amine-diol structure chelates metal ions, which underlies its contribution in cement chemistry and in corrosion inhibition.

DIPA vs MIPA, TIPA and the Ethanolamines

The isopropanolamines are the propylene oxide counterparts of the ethanolamines, and the comparison that matters most to a buyer runs across that divide rather than within the family. Swapping ethylene oxide for propylene oxide adds a methyl group to each arm, which makes the molecule bulkier, more oil-compatible, less prone to foaming — and turns the secondary hydroxyl into a slower, more selective reaction partner.

Stated plainly: the extra methyl group on each arm makes the isopropanolamines less foaming and more oil-tolerant than the ethanolamines, which is why metalworking fluid formulators favour MIPA over MEA. In cement, TIPA and TEA do genuinely different jobs — TEA improves grinding efficiency and early strength, TIPA improves late strength by complexing the iron phases — which is why commercial grinding aid packages routinely contain both rather than choosing one. They are complements more often than substitutes.

Industries We Supply DIPA To

The same molecule leaves our warehouse for very different factories. What changes between them is not the CAS number but the form — flake or 85% solution — the grade, and the documentation each sector expects.

Where DIPA is Used

DIPA's defining market is selective gas treating, with a broader set of formulating uses alongside it. These are the end uses our customers buy it for.

In selective gas treating

This is DIPA's distinctive application and the reason it exists as a product rather than as a curiosity. In many gas streams you want the hydrogen sulphide removed and much of the carbon dioxide left alone — because the carbon dioxide is harmless downstream, because removing it costs energy, or because a sulphur recovery unit needs a concentrated hydrogen sulphide feed to run properly. An unhindered amine takes both out indiscriminately. DIPA's steric bulk destabilises the carbon dioxide carbamate while leaving hydrogen sulphide absorption, which is a simple proton transfer, completely unaffected. The result is a solvent that can be tuned to pull one gas and largely leave the other.

In carbonyl sulphide removal

Carbonyl sulphide is a persistent nuisance in many gas streams: it is not removed by ordinary amine absorption, and with some amines it reacts irreversibly to form degradation products that then have to be reclaimed out of the solvent inventory. DIPA hydrolyses COS to hydrogen sulphide and carbon dioxide, which it then absorbs normally. That turns a degradation problem into a removal capability, and it is a major part of why DIPA persists in refinery service.

In cement grinding aids

DIPA appears in grinding aid and strength-enhancer packages alongside TEA, TIPA and MIPA. The mechanism is the familiar one — adsorption onto fresh fracture surfaces during milling prevents agglomeration and media coating — with an additional contribution from metal complexation in the hydrating cement. Dosage is very low, so consistency between deliveries matters more than absolute purity.

In metalworking and industrial fluids

As with MIPA, the methyl groups mean lower foaming than the corresponding ethanolamine, which matters in a recirculating fluid. DIPA contributes alkalinity reserve and emulsification. Formulators should note that it is a secondary amine and therefore nitrosatable, which is the consideration that drove much of this industry away from diethanolamine — the same question applies here and deserves a deliberate assessment.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis. The methods behind the numbers are standard across the industry, and we are happy to share them or to work to your own in-house test protocol.

• Assay and isopropanolamine distribution — gas chromatography, quantifying MIPA and TIPA carry-over. For gas treating the MIPA figure specifically affects selectivity.
• Melting point — a fast, revealing check. A depressed melting point indicates water or cross-contamination before any instrument confirms it.
• Water content — Karl Fischer titration on flake grade, which is hygroscopic once a bag is opened.
• Iron and chloride — critical for gas treating, where both drive corrosion and solvent degradation in a hot circuit.
• Colour — APHA / Hazen on melted material against a standard.
• Non-volatile residue — evaporation residue, a check on heavies that would accumulate in a recirculating solvent.

Common Process Problems & Likely Causes

When DIPA misbehaves in a plant, the cause is usually one of a short list of things. This table is the shortcut our technical desk works through before anyone opens a complaint file.

Packaging, Storage & Shipping

• Flake packing. 25 kg net in multi-wall paper bags with a polyethylene liner, or in HDPE-lined fibre drums. Moisture-barrier packaging matters, since the flake is hygroscopic.
• Solution grade. 85% aqueous solution in 1000 L IBCs and bulk tanks — the practical choice for most plants that would otherwise be melting solid.
• Bulk packing. Heated road tankers and heated ISO tank containers for gas plants and continuous users.
• Melting and handling. DIPA is solid below about 42 °C. Drum heaters, hot rooms or heated storage are normal, and lines need tracing and lagging. Heat gently and evenly — local overheating darkens the product permanently.
• Materials of construction. Stainless steel or suitable lined vessels. Carbon steel is used in some service but corrodes more readily when the amine is hot or loaded with acid gas. Avoid copper, brass, bronze and aluminium.
• Oxygen exclusion. The ethanolamines oxidise and darken on air contact, particularly when warm. Nitrogen blanketing is standard for colour-sensitive grades and for any heated storage.
• Shelf life. Typically 12 months in unopened original packing under those conditions. Beyond that, re-test rather than assume.
• Nitrite segregation. As a secondary amine, DIPA should be stored and handled away from nitrites and other nitrosating agents.
• Transport classification. Diisopropanolamine is generally not classified as dangerous goods for transport, though it is classified for supply. Confirm against the current SDS for your destination and mode.

Hazards & Safe Handling

Diisopropanolamine is an irritant and a secondary amine with an associated nitrosamine consideration. It must be handled by trained personnel under a proper risk assessment. The classifications below are indicative — the current SDS supplied with your consignment is the governing document.

• Nitrosamine consideration. DIPA is a secondary amine and can be nitrosated in the presence of nitrosating agents. Keep nitrites out of the handling area, segregate in storage, and design formulations so the two cannot meet. Where a finished product falls under a nitrosamine limit scheme, assess this at the design stage.
• Hot and molten material. Melting and heated storage introduce thermal burn risk and raise vapour and mist exposure. Treat heated handling as a separate operation with its own controls.
• Dust control. Handling flake generates dust. Enclosed transfer and local exhaust at charging points are the standard controls, and are a practical argument for the solution grade.
• PPE. Chemical-resistant gloves, chemical goggles and face shield, chemical-resistant clothing, and respiratory protection where flake dust is generated.
• Exposure control. Vapour pressure is very low at ambient, so skin, eye and dust contact dominate rather than vapour inhalation.
• Incompatibilities. Strong oxidising agents, strong acids, acid chlorides, nitrites, and copper, brass, bronze and aluminium equipment.
• Spill response. Collect solid mechanically without raising dust; contain and absorb liquid with inert material. Collect in a labelled closed container. Do not wash to drain.
• First aid. Remove contaminated clothing, wash skin with plenty of water, flush eyes for at least 15 minutes, and seek medical attention with the SDS to hand.

Regulatory & Compliance Notes

Diisopropanolamine is an established industrial chemical and is listed on the major national chemical inventories. Because obligations differ by territory, volume and use, the notes below are orientation rather than legal advice — confirm your own position with your regulatory adviser before importing.

• Inventory status. Listed on the principal chemical inventories in the major importing regions. Ask us for the inventory confirmation relevant to your destination country.
• Import registration. Several territories require the importer to hold a registration or notification before a consignment lands. Start that process early — it is the most common cause of delay at destination.
• Hazard communication. Supplied with an SDS compliant with the format applicable to your region, and labelled in line with the GHS classification for the product.
• Nitrosamine controls. As a secondary amine, DIPA falls within the scope of nitrosatable-amine restrictions that apply in cosmetics, metalworking fluids and some other sectors. Confirm the position for your product category at destination before specifying it for consumer-contact use.
• Abbreviation clash. DIPA is used for both diisopropanolamine, CAS 110-97-4, and diisopropylamine, CAS 108-18-9. They are entirely different substances with different inventory entries, hazard classifications and transport status. Confirm the CAS number on every enquiry and every declaration.
• Dangerous goods. Generally not classified as dangerous goods for transport, though classified for supply. Confirm against the current SDS for your destination and mode.

We Supply DIPA Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Diisopropanolamine from India to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation, dangerous-goods paperwork and freight so the material arrives ready to use.

• Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
• Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other Indian ports arranged where it suits the routing.
• Documentation. Commercial invoice, packing list, certificate of origin, COA, SDS and dangerous-goods declaration issued as a complete set.
• Flexible volumes. A single drum for laboratory qualification, through LCL consolidations, up to repeat full loads on a supply contract.
• Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.

Buying DIPA from Chelora

We are an independent sourcing and supply partner. For DIPA that means settling three things before quoting: that the enquiry means diisopropanolamine rather than diisopropylamine, which physical form your plant can handle, and whether the duty is selective gas treating — because that last answer makes MIPA carry-over the governing specification.

• Documentation on every lot. Batch-specific COA, current SDS and TDS issued with the consignment, not weeks afterward.
• Both forms. Flake and 85% aqueous solution, matched to how your plant handles material.
• Samples before commitment. Trial quantities for process qualification ahead of a commercial order.
• Quantities. From a single 25 kg bag through to heated bulk tank loads on contract supply.
• Export experience. Full documentation, packing and labelling handled for sea and road freight to any destination.
• Related intermediates. MIPA, TIPA, MEA, DEA, MDEA and the wider gas-treating amine range from one supplier.

How ordering works

• Send the enquiry. Product, grade or specification, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
• We quote. Price, lead time, packing and a sample COA, normally within one working day.
• Sample and qualify. For first orders or critical applications, we send a trial quantity so your lab can sign off before you commit.
• Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
• Production and QC. Material allocated and released against a batch-specific COA, with a pre-shipment sample where the application calls for it.
• Ship and document. Packed, labelled and loaded with the full export and dangerous-goods document set, and tracked through to arrival.

Related Alkanolamines & Gas-Treating Amines

Buyers of DIPA usually source several of these alongside it. Consolidating them on one order cuts freight cost and gives you a single point of contact for documentation.