Sciencemadness Discussion Board

Storage group for Phthalic Anhydride

SuperOxide - 15-2-2025 at 08:56

I was working on getting all the reagents I have properly organized and inventoried as best I can. For segregation I was going with the somewhat common A, B, C, etc groups that can be found documented in several colleges. Here's an example.

I have like 200g of phthalic anhydride. When I looked up what group to store it with (thinking it would be with D - compatible organic acids), I was surprised to find that it's listed as being under group "X".
Quote:
X - Incompatible with ALL other storage groups

I thought maybe this was just a mistake, but several other sources have it under X as well.

Why would phthalic anhydride be considered reactive enough that it can't be stored with other reagents? I get that acid anhydrides can be very reactive, but when I think of phthalic anhydride, I don't think of a particularily reactive substance.

teodor - 16-2-2025 at 02:24

I'd like to say that there are different systems to classify reagents for storage. I, for example, use this one:

Attachment: lab_chemical_storage_guide.pdf (458kB)
This file has been downloaded 58 times

Most developed are systems based on fire hazard (NFPA standard), chemical storage in production (10-100kg+ of a particular chemical) and transportation. From other points of view the principles can vary.

From NFPA 49:

NAME: PHTHALIC ANHYDRIDESYNONYMS: 1,3-dioxophthalan; 1,3-isobenzo- furandione; PAN; phthalandione FORMULA: C6H4(CO)2O
NFPA 30/OSHA CLASSIFICATION: IIIB
DOT CLASS: Class 8, Corrosive material
SHIPPING LABEL: CORROSIVE310
ID NO.: UN 2214
CAS NO.: 85-44-9 MOL. WT.: 148.1
STATEMENT OF HAZARDS: Corrosive. Combustible solid. EMERGENCY RESPONSE PERSONAL PROTECTIVE EQUIPMENT: Wear special protective clothing and posi- tive pressure self-contained breathing apparatus. SPILL OR LEAK PROCEDURES: Keep water away from re- lease. Prompt cleanup and removal are necessary. Shovel into suitable dry container. FIRE FIGHTING PROCEDURES: Use dry chemical, foam, carbon dioxide, or water spray. Water or foam may causefrothing. Approach fire from upwind to avoid hazardous vapors and toxic decomposition products. HEALTH HAZARDS: Corrosive. Causes severe eye and skin burns. May be armful if inhaled. Symptoms of overexposureinclude ulcer bleeding, upper respiratory irritation, bron- chitis, asthma, and dermatitis. FIRE AND EXPLOSION HAZARDS: Combustible solid. Dustmay form explosive mixtures with air. FLASH POINT: 305F (152C) AUTOIGNITION TEMPERATURE: 1058F (570C) FLAMMABLE LIMITS: LOWER: 1.7% UPPER: 10.4%
STORAGE RECOMMENDATIONS: Store in a cool, dry, well- ventilated location. Separate from acids, alkalies, oxidizingmaterials, reducing agents, and moisture.
USUAL SHIPPING CONTAINERS: Lined fiber bags. As mol- ten material in heated tanks on trucks, rail cars, barges. PHYSICAL PROPERTIES: White, lustrous needles. Charac- teristic choking odor. MELTING POINT: 268F (131C) BOILING POINT: 544F (285C) SPECIFIC GRAVITY: 1.53 SOLUBILITY IN WATER: not soluble VAPOR PRESSURE: 1 mm Hg @ 96C

I think in the case of the system of storage you are reffering to it is based on NFPA 49 statement "STORAGE RECOMMENDATIONS" above (not compatible with acids, bases etc) but NFPA itself assigns the storage class IIIB. In any case, I think it is not a precise system and based on some person opinion who made the decision.

But in any case it is important to understand as much properties of a compound as possible.

And obvioisly, in practice of a home lab some other consideration could be more important, than those those standards are based upon. For example, I find it very convenient to store all products and intermediates of some particular experiment in a single plastic container. Acessibility of dangerous chemicals for accidental visitors (children) is important. Ventilation and dry conditions are important. Taking in consideration that the space was not designed as a lab, making the best lab in a house is a piece of art, knowledge and practice. So, keep experimenting, this is the most important thing also for safety.

[Edited on 16-2-2025 by teodor]

SuperOxide - 16-2-2025 at 05:26

Quote: Originally posted by teodor  
I'd like to say that there are different systems to classify reagents for storage. I, for example, use this one:

That's a very helpful chart, thanks! It actually goes pretty well with the system I shared, but it'll help me categorize them into the proper groups myself since not all chemicals are listed.
Quote: Originally posted by teodor  

I think in the case of the system of storage you are reffering to it is based on NFPA 49 statement "STORAGE RECOMMENDATIONS" above (not compatible with acids, bases etc) but NFPA itself assigns the storage class IIIB. In any case, I think it is not a precise system and based on some person opinion who made the decision.

But in any case it is important to understand as much properties of a compound as possible.

That's what I figured. And maybe the other universities just copied whoever put it in Group X initially, lol.

teodor - 17-2-2025 at 01:22

Quote: Originally posted by SuperOxide  
Quote: Originally posted by teodor  
I'd like to say that there are different systems to classify reagents for storage. I, for example, use this one:

That's a very helpful chart, thanks! It actually goes pretty well with the system I shared, but it'll help me categorize them into the proper groups myself since not all chemicals are listed.


Exactly. It depicts some principle which you can understand.
But the most important thing is to store chemicals in a dry place, at the proper temperature and not on a direct sunlight. The next thing is the ability to find any chemical fast, and when you know the principle how they are separated and can figure out the group without an error and without checking the list it is a big plus.

SuperOxide - 18-2-2025 at 19:18

Quote: Originally posted by teodor  
Quote: Originally posted by SuperOxide  
Quote: Originally posted by teodor  
I'd like to say that there are different systems to classify reagents for storage. I, for example, use this one:

That's a very helpful chart, thanks! It actually goes pretty well with the system I shared, but it'll help me categorize them into the proper groups myself since not all chemicals are listed.


Exactly. It depicts some principle which you can understand.
But the most important thing is to store chemicals in a dry place, at the proper temperature and not on a direct sunlight. The next thing is the ability to find any chemical fast, and when you know the principle how they are separated and can figure out the group without an error and without checking the list it is a big plus.


I just invested in an explosion proof freezer and two corrosive storage cabinets, each of which have plenty of secondary HDPE containers to separate the groups as needed (hence why im getting organized, lol). Definitely an upgrade from how I was storing everything before (acids/bases/oxidizers/etc in separate 5 gal buckets with some leak proof lids that were not so leak proof).

[Edited on 19-2-2025 by SuperOxide]