# Isopropyl alcohol

Isopropanol identity, commercial grades, concentration bases, condition-specific physical data, and the limits of technical and safety documents.

Reviewed: 2026-10-30

Tags: chemicals, solvents, substances

## Identity and related substances

Solstice **190764 ACS** specifies **≥99.50% by GC** and **≤0.2% water by Karl Fischer**. **34965 LC-MS** specifies **≥99.9% by GC** and **≤0.05% water**. These limits identify grades. Isopropyl alcohol (IPA, isopropanol, 2-propanol) is C₃H₈O, CAS 67-63-0, 60.0950 g/mol, InChIKey KFZMGEQAYNKOFK-UHFFFAOYSA-N. [NIST Chemistry WebBook, SRD 69](https://webbook.nist.gov/cgi/cbook.cgi?ID=C67630&Mask=4)

In (CH₃)₂CHOH the hydroxyl is on the middle carbon. 1-Propanol shares the molecular formula and has CAS 71-23-8. [Solstice 190764, identity](https://lab.solstice.com/shop/2-propanol-190764) [NIST 1-propanol](https://webbook.nist.gov/cgi/cbook.cgi?ID=C71238)

## Commercial grades and analytical meaning

These manufacturer catalog specifications illustrate two grades of the same substance. They are product limits, not measured results for every lot.

| Solstice product | Assay minimum | Water maximum | Nonvolatile matter maximum | Additional specification example |
| --- | --- | --- | --- | --- |
| Fluka 190764, ACS reagent | 99.50%, GC | 0.2%, Karl Fischer | 0.001% | Carbonyl compounds as acetone: 0.002% maximum |
| CHROMASOLV 34965, LC-MS | 99.9%, GC | 0.05%, Karl Fischer | 0.0005% | Iron: 0.1 ppm maximum |

Sources: [190764 specification table](https://lab.solstice.com/shop/2-propanol-190764), [34965 specification table](https://lab.solstice.com/shop/2-propanol-34965). GC means gas chromatography. The pages do not declare the concentration basis for every percentage or supply the full GC calculation method. Both provide a separate lot-number certificate of analysis lookup.

Synthesis: a GC assay percentage without a declared mass basis and calculation method does not establish whole-product mass composition. The separate water and residue limits cannot be inferred from the assay minimum. Neither catalog establishes a current lot's impurity profile, uncertainty, or fitness for a manufacturing application. No lot certificate was reviewed.

## Aqueous products and concentration bases

Fisher's A459-4 product title specifies **70% v/v**. Its assay field gives 68.0–72.0% without repeating the basis or stating a reference temperature. The corresponding US SDS lists **64.7 weight % isopropyl alcohol and 35.3 weight % water** in section 3. These are different concentration bases, rather than interchangeable meanings of “70%.” [Fisher A459-4 catalog](https://www.fishersci.com/shop/products/ipa-isopropyl-alcohol-70-v-v-fisher-chemical-4/a4594), [Fisher A459 SDS, revision 10, December 18, 2025](https://www.fishersci.com/store/msds?countryCode=US&language=en&partNumber=A4594&productDescription=ISOPROPYL+ALCOHOL+4LT&vendorId=VN00033897)

Synthesis: mass percentage expresses constituent mass relative to total mass. A volume-based designation also depends on its volume convention and reference temperature. A numerical conversion needs those definitions and appropriate density data. The two manufacturer statements do not establish a conversion equation, volumetric preparation, or a current lot's assay. The pure compound's formula describes the alcohol component, not the entire aqueous product.

## Physical properties and conditions

Shell's May 2022 European S1111 technical datasheet labels its values **typical properties**. It describes IPA as a solvent for epoxy and acrylic resins. The following values apply to that reference product. [Shell S1111 technical datasheet, pages 1–3](https://www.shell.com/content/dam/shell/assets/en/business-functions/product/helix/documents/ipa-s1111-eu.pdf)

| Property | Shell value | Method or missing basis |
| --- | --- | --- |
| Purity minimum | 99.8% m/m | GC |
| Water | 0.03% m/m | ASTM D1364 |
| Liquid density at 20 °C | 0.785 kg/L | ASTM D4052 |
| Dynamic viscosity at 20 °C | 2.4 mPa·s | Method unspecified |
| Specific heat at 20 °C | 2.56 kJ/(kg·°C) | Method unspecified |
| Heat of vaporization at boiling temperature | 664 kJ/kg | Method unspecified |
| Water miscibility at 20 °C | Complete in both directions | Method unspecified |

Source: [Shell S1111, tables and method footnote](https://www.shell.com/content/dam/shell/assets/en/business-functions/product/helix/documents/ipa-s1111-eu.pdf). No pressure basis accompanies these physical values. Shell allows validated local methods for routine quality control. Its contract disclaimer does not warrant application suitability.

Solstice 34965 gives density 0.784–0.786 g/cm3 and viscosity 2.5 mPa·s at 20 °C, without methods or pressure. [Solstice 34965, properties](https://lab.solstice.com/shop/2-propanol-34965)

Synthesis: kg/L and g/cm3 are equivalent density units. The density interval includes Shell's value, but the viscosity difference has no established cause here. Source precision, grade, and unspecified methods prevent assigning it to any one factor. Complete miscibility does not establish aqueous-mixture density, viscosity, or compatibility with a workpiece, seal, or coating.

## Phase equilibrium and vapor pressure

NIST's boiling-point average is **355.5 ± 0.4 K**, from 102 of 118 values. Its fitted Antoine equation is `log10(P) = A - B / (T + C)`, with **P in bar** and **T in kelvin**. [NIST phase-change tables, references, and notes](https://webbook.nist.gov/cgi/cbook.cgi?ID=C67630&Mask=4)

| Valid temperature interval, K | A | B | C | Underlying reference |
| --- | --- | --- | --- | --- |
| 329.92–362.41 | 4.8610 | 1357.427 | -75.814 | Biddiscombe and colleagues, 1963 |
| 395.1–508.24 | 4.57795 | 1221.423 | -87.474 | Ambrose and Townsend, 1963 |

Source: [NIST Antoine parameters](https://webbook.nist.gov/cgi/cbook.cgi?ID=C67630&Mask=4). Neither interval includes 20 °C.

Nonprocedural calculation: at 333.15 K, or 60 °C, the first correlation gives approximately **0.3855 bar**, or **38.55 kPa**. This pure-substance saturation pressure has no supplied fit uncertainty. Synthesis: saturation pressure alone does not establish mixture pressure or airborne concentration.

Shell lists calculated vapor pressure of 4.1 kPa at 20 °C. Solstice 190764 lists both 33 mmHg and 42 hPa at 20 °C. Unit conversion gives approximately 4.40 and 4.20 kPa, respectively. The discrepancy remains unresolved. [Shell S1111, page 2](https://www.shell.com/content/dam/shell/assets/en/business-functions/product/helix/documents/ipa-s1111-eu.pdf), [Solstice 190764, specifications and properties](https://lab.solstice.com/shop/2-propanol-190764)

Solstice's boiling range is printed as 77–83 °C at `1.013 hPa`. That punctuation leaves the intended pressure ambiguous. Neither this entry nor Fisher's aqueous SDS boiling-point entry supplies enough verified context to establish aqueous phase equilibrium here. [Solstice 34965](https://lab.solstice.com/shop/2-propanol-34965), [Fisher SDS, section 9](https://www.fishersci.com/store/msds?countryCode=US&language=en&partNumber=A4594&productDescription=ISOPROPYL+ALCOHOL+4LT&vendorId=VN00033897)

## Regional hazard classification

Fisher's A459 US SDS, revision 10 dated December 18, 2025, follows OSHA HCS 2024. It classifies the designated aqueous product as flammable-liquid category 2, eye-irritation category 2, and single-exposure target-organ toxicity category 3 affecting the central nervous system. Section 16 states that the SDS is not a quality specification or warranty. [Fisher SDS, sections 1–3 and 16](https://www.fishersci.com/store/msds?countryCode=US&language=en&partNumber=A4594&productDescription=ISOPROPYL+ALCOHOL+4LT&vendorId=VN00033897)

Synthesis: this dated product classification does not establish every IPA formulation's classification, current legal compliance in another region, material compatibility, or process performance. Hazard documentation and analytical specifications answer different questions.

## Source versions and coverage limits

Sources were reviewed on October 30, 2026 PDT. Shell's datasheet is dated May 2022. The Solstice and Fisher catalog pages provide no numbered technical revision. NIST SRD 69 supplies the cited compilation and correlations. The original 1963 experimental papers were not reviewed in full.

Coverage excludes current lot certificates, detailed GC methods, aqueous density and vapor-liquid equilibrium correlations, additive-containing formulations, and material-specific compatibility tests. No commercial grade establishes customer approval. The related [Surface-finishing processes](../../processes/finishing/index.md) supplies broader process context.