Molekula
Trimethyl phosphite
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 2000 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Trimethyl phosphite (CAS 121-45-9) is a colorless liquid organophosphorus compound widely used as a reagent in organic synthesis, particularly for the preparation of phosphonates, phosphine oxides, and as a methylating agent in chemical research and industrial processes. It is also employed in pesticide and flame-retardant production. This chemical has the molecular formula C3H9O3P and a molecular weight of 124.08. It should be stored at ambient conditions but handled with care due to its **Danger** classification under GHS, requiring proper protective measures. Molekula supplies Trimethyl phosphite from research to bulk quantities with full documentation and ISO 9001:2015 traceability.
Example image for illustration only. Other packaging and pack sizes are available.
Pricing & pack sizes
These pack sizes aren't a limit. Molekula manufactures, sources and repacks to order — if you need 500 kg and only see 1 kg listed, . We quote from grams to multi-tonne.
Need a different size? Add the nearest pack and change the size in your basket — we price it at the same rate per unit.
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100 g — £68.50 per pack ex VAT · £82.20 inc. VAT
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Tell us how much you need and when — drums, IBCs, sacks or a one-off bulk lot. We'll manufacture or source it and come back with a price.
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Specifications
| Property | Value |
|---|---|
| Appearance | Clear, Colourless Liquid |
| Boiling Point | 109°C to 113°C |
| Assay (GC) | ≥97.00% |
| Identification (IR) | Passes test |
| Refractive Index (n20/D) | 1.4040 to 1.4050 |
| Wt. per mi. at 20°C | 1.0510g to 1.0530g |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
| Flash Point | 28 °C |
| Transport Class | 3 |
| Packing Group | III |
| Acidity | Base |
Literature values
Published physical properties of the substance, not batch specifications.
| Property | Value |
|---|---|
| Appearance | Colorless liquid |
| Odour | Irritating, pungent, oily, pyridine-like odor |
| Melting Point | -78 °C |
| Boiling Point | 110 °C |
| Density | 1.1 (relative, water = 1) |
| Solubility (other solvents) | Very soluble in ethanol, ether |
| Vapour Pressure | 3.2 kPa at 25 °C |
| Refractive Index | 1.4095 |
Source: PubChem CID 8472 (HSDB, ICSC)
Identification
| Property | Value |
|---|---|
| SKU | 89967933 |
| CAS Number | 121-45-9 |
| IUPAC Name | trimethyl phosphite |
| EC Number | 204-471-5 |
| Molecular Formula | C3H9O3P |
| Molecular Weight | 124.08 |
| Exact Mass | 124.0289 |
| SMILES | COP(OC)OC |
| InChIKey | CYTQBVOFDCPGCX-UHFFFAOYSA-N |
| InChI | InChI=1S/C3H9O3P/c1-4-7(5-2)6-3/h1-3H3 |
| PubChem CID | 8472 |
| UN Number | UN2329 |
| REACH Code | Y110 |
| TSCA Listed | Yes |
| HTS Code | 2920.23.0000 |
| Tariff Code | 2920230000 |
Safety & GHS
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Flammable
GHS02
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Corrosive
GHS05
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Toxic
GHS06
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Health Hazard
GHS07
Hazard statements
- EUH014 Reacts violently with water
- H226 Flammable liquid and vapour
- H302 Harmful if swallowed
- H311 Toxic in contact with skin
- H315 Causes skin irritation
- H318 Causes serious eye damage
- H335 May cause respiratory irritation
Precautionary statements
- P210 Keep away from heat/sparks/open flames/hot surfaces - No smoking
- P261 Avoid breathing dust/fume/gas/mist/vapours/spray
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P301+312 IF SWALLOWED: Call a POISON CENTER or doctor/physician if you feel unwell
- P302+350 IF ON SKIN: Gently wash with soap and water
- P305+351+338 IF IN EYES: Rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, Portuguese, Spanish.
Certificate of Analysis (CoA) by batch
Enter a lot or batch number to retrieve the CoA for that specific batch. We can generate one from spec data if no PDF is on file.
Synonyms
- Fosforyn trojmetylowy
- Methyl phosphite
- Methyl phosphite ((MeO)3P)
- P(OMe)3
- Phosphorous acid, trimethyl ester
- Trimethoxyfosfin
- Trimethoxyphosphine
- Trimethyl ester of phosphorous acid
- Trimethyl Ester Phosphorous Acid; NSC 6513; Trimethoxyphosphine;
- Trimethylfosfit
Frequently asked questions
What is trimethyl phosphite (CAS 121-45-9) commonly used for?
Trimethyl phosphite is primarily used as a reagent in organic synthesis, including the preparation of phosphonates, phosphines, and as a methylating agent in various chemical reactions.
What is the molecular formula and molecular weight of trimethyl phosphite?
The molecular formula is **C₃H₉O₃P**, and the molecular weight is **124.08 g/mol**.
How should trimethyl phosphite be stored?
Store at **ambient temperature** in a tightly sealed container, away from moisture, oxidizing agents, and sources of ignition.
What grades or purities of trimethyl phosphite does Molekula supply?
Molekula supplies **technical grade** and **high-purity (HPLC/GC grade)** trimethyl phosphite, depending on your application requirements.
Can Molekula supply trimethyl phosphite in bulk quantities?
Yes, we offer trimethyl phosphite in bulk, with packaging options including drums (200L) and IBCs (1000L), subject to order volume and safety compliance.
What documentation comes with a trimethyl phosphite order?
Each order includes a **Certificate of Analysis (CoA)**, **Material Safety Data Sheet (MSDS/SDS)**, and a **packing list** with batch-specific details.
Ready to order or need a custom pack?
Tell us the product, grade, and quantity — Molekula usually responds within one working day with pricing and lead time.