Short answer. On receipt, check the batch number, then read four lines of the Certificate of Analysis against IS 5149:2020: maleic anhydride content (99.2% mass min), maleic acid (0.8% mass max), crystallizing point (52.1 C min) and colour (20 APHA max). Then open a bag and look at the flakes. A high maleic acid figure or hard lumps point to moisture. Supreme Petro Chemicals is a Chennai trader and bulk distributor, not a manufacturer, and supplies a batch CoA with every delivery.
This guide is about the receiving step: what to do in the first ten minutes after a consignment of maleic anhydride arrives. The full specification table, hazard data, packs and transport details are on the product page, so they are not repeated here. What follows is a working routine, two worked examples and a diagnosis checklist. Wherever a statement is general chemistry or general practice rather than SPC product data, it is marked as such.
Why a receiving check is worth doing
Maleic anhydride is the anhydride of maleic acid. Our safety data sheet states that it reacts with water to form maleic acid. Every flake that has already picked up water is a flake that is no longer behaving as the anhydride you ordered. The certificate tells you the state of the batch at the time it was tested; the bags in front of you tell you what happened since. A receiving check connects the two.
The grade SPC lists is IS 5149:2020, documented on the manufacturer's certificate of quality in technical data sheet SPC-TDS-ANH-002. The limits you are checking against are: content 99.2% mass min, maleic acid 0.8% mass max, crystallizing point 52.1 C min, colour of molten material 20 APHA max, ash 0.005% mass max, iron 10 ppm max, and an appearance of white flakes with no visible impurities.
Step 1: match the paperwork to the bags
As general practice, start with identity before numbers. The batch number printed on the certificate should be the batch number on the bags. If a delivery contains more than one batch, you need one certificate per batch. Note the pack type as well. The lead pack in our data sheet is the 25 kg bag, and a 25 kg carton with PE liner and a 1000 kg jumbo bag can be quoted, so check that what arrived is what was ordered.
Also confirm the standard named on the certificate is IS 5149:2020 and that each parameter in the list above is reported. A certificate that reports only content and nothing else is a prompt to ask a question, not a reason to reject the lot on its own.
Step 2: read each line in the right direction
Some limits are minimums and some are maximums, and mixing them up is the most common reading error. Content and crystallizing point are minimums: the reported value must be at or above the limit. Maleic acid, colour, ash and iron are maximums: the reported value must be at or below the limit.
Check units as well. Content, maleic acid and ash are in % mass, iron is in ppm and colour is in APHA. As general practice, if a certificate reports in a unit you do not recognise, ask for it to be restated before you accept the result.
Crystallizing point is not melting point
Two temperatures circulate around this product. The crystallizing point (52.1 C min) is a specification test. The melting point in our safety data sheet, about 52 to 53 C, is a literature value to be verified against the certificate. Do not compare one with the other. Look for the crystallizing point line on the certificate and compare that against 52.1 C. As general practice, a certificate that gives only a melting range does not answer the specification question.
Worked example 1: a certificate that passes
The figures below are invented for illustration only. They are not a real batch and not a typical result.
| Parameter | Limit | Illustrative result | Verdict |
|---|---|---|---|
| Maleic anhydride content | 99.2% min | 99.6% | Pass |
| Maleic acid | 0.8% max | 0.3% | Pass |
| Crystallizing point | 52.1 C min | 52.7 C | Pass |
| Colour (molten) | 20 APHA max | 12 APHA | Pass |
| Ash | 0.005% max | 0.002% | Pass |
| Iron (as Fe) | 10 ppm max | 5 ppm | Pass |
Every line sits on the correct side of its limit, the units match, and the content and acid figures are consistent with each other: the anhydride and its hydrolysis product together account for essentially all of the material. If the bags are intact and the flakes look white and free-flowing, this lot can be accepted.
Worked example 2: a certificate that fails
Again, these figures are invented to show the reading method.
| Parameter | Limit | Illustrative result | Verdict |
|---|---|---|---|
| Maleic anhydride content | 99.2% min | 98.7% | Fail |
| Maleic acid | 0.8% max | 1.3% | Fail |
| Crystallizing point | 52.1 C min | 51.4 C | Fail |
| Colour (molten) | 20 APHA max | 18 APHA | Pass |
Three lines fail together, and they fail in a related way: content down, acid up and crystallizing point down. That pattern is what moisture damage looks like on paper, because the acid has formed at the expense of the anhydride. As general chemistry, impurity also lowers a crystallizing point, so the three figures reinforce one another. The colour line passing does not rescue the lot. Raise this with your supplier before the material goes into a reactor, and keep the certificate with the bag photographs.
Notice that none of the failing numbers is dramatic on its own. A content of 98.7% looks close to 99.2%. The value of reading all lines together is that a small miss on three correlated lines is a clearer warning than a large miss on one.
Step 3: look at the flakes
Open one bag, or the carton liner, and inspect before you weigh anything. The specification calls for white flakes with no visible impurities. Moisture exposure shows up in ways you can see and feel:
- Flakes that have fused into hard lumps rather than flowing freely (general observation; the effect of damp on a solid that reacts with water).
- A surface that looks wet, glazed or crusty.
- Torn, punctured or unsealed bags and liners.
- A sharp, acrid smell stronger than you expect when the bag is first opened. Treat this as a prompt to use ventilation and your PPE, not as a test.
Do the inspection with the protective equipment the safety data sheet calls for: local exhaust ventilation, nitrile, butyl or neoprene gloves, and splash goggles. The product is corrosive and a respiratory and skin sensitiser, so the full hazard data on the product page should be read before anyone opens a bag.
Diagnosing moisture damage: a checklist
If the certificate or the flakes raise doubts, work through these questions in order.
- Was the problem there at dispatch or did it develop after? Compare the certificate figure with a fresh sample from an unopened bag. If the certificate is clean and the fresh sample is not, look at storage and transit.
- Were the bags sealed on arrival? Damaged liners are the usual entry route for humid air.
- How long and where has it been stored? Shelf life in our product data is 24 months from manufacture, kept sealed, cool and dry. Humid weather and open bags shorten the useful life of an opened pack.
- Has the same bag been opened repeatedly? As general practice, reseal after each draw and use clean, dry tools.
- Is the damage confined to the top layer? Surface lumps with sound material below suggest limited exposure; lumps throughout suggest a packing or transit problem.
For wider habits that apply to every chemical on your floor, see the chemical storage and handling basics guide.
What to do with a suspect lot
Quarantine it, keep it sealed, and do not mix it with accepted material. Send the batch number, the certificate and photographs to your supplier and ask for a resolution. If you use the anhydride in resin work, a trial on a small quantity is a decision for your own process engineers. No claim is made here about how any particular recipe will respond.
Context in the resin chain
Resin makers usually buy this anhydride alongside phthalic anhydride, which has a very different crystallizing point (130.8 C min) and caps maleic anhydride as an impurity at 0.1% mass max. The maleate ester DOM (di-octyl maleate) is derived from maleic anhydride, and the alkyd resin page covers one of the resins it goes into. The IS 5149:2020 grade is a technical grade for industrial or professional use; it is not a food or pharma grade.
Get the documents and a quote
Review the data sheets on the maleic anhydride IS 5149:2020 flakes page, then send your quantity, pack type and destination. We quote within 4 working hours and supply a batch Certificate of Analysis with every delivery. Supreme Petro Chemicals is a Chennai trader and bulk distributor, not a manufacturer. Always verify current carrier and regulatory requirements for your own shipment.