DrDNA Posted February 3, 2009 Posted February 3, 2009 Hydrazoic Acid (HN3); the propellant that makes air bags inflate. I have several colleagues that lost fingers to exothermic reactions that got away from them while using this stuff.
John Cuthber Posted February 3, 2009 Posted February 3, 2009 You listed RDX twice. Also, to add on to what nitric said RDX is also incredibly stable. Apparently C-4, consisting primarily of RDX, can be shot with a rifle and lit on fire without detonating.Also, nice point with the alcohol. I was just testing to see if anyone read the list. The RMX should be HMX.
npts2020 Posted February 3, 2009 Posted February 3, 2009 Water is one of the most dangerous substances I have ever handled, cleaning up a spill of primary coolant (water that has been through a reactor) at a nuclear power plant.
DrDNA Posted February 3, 2009 Posted February 3, 2009 "Drowning Deaths per year: 4,000 This includes all sorts of drownings in boat accidents and those resulting from swimming, playing in the water, falling in, or even having a bath. The human body is what, 70% water? And we begin our lives in a watery environment, there's lots of oxygen in water what's the deal? Something for the scientists to work on." http://www.soyouwanna.com/site/toptens/accidents/accidentsfull.html
npts2020 Posted February 4, 2009 Posted February 4, 2009 "DrowningDeaths per year: 4,000 This includes all sorts of drownings in boat accidents and those resulting from swimming, playing in the water, falling in, or even having a bath. The human body is what, 70% water? And we begin our lives in a watery environment, there's lots of oxygen in water what's the deal? Something for the scientists to work on." http://www.soyouwanna.com/site/toptens/accidents/accidentsfull.html You would have had a hard time drowning in the puddles I dealt with. However you could have easily exceeded your allowable annual radiation dose at a single clean-up if you were not careful or didn't know what you were doing.
John Cuthber Posted February 4, 2009 Posted February 4, 2009 OK, but it wasn't the water that was a hazard was it? What radioisotopes were you sloshing about?
inuhbad Posted February 4, 2009 Posted February 4, 2009 "DrowningDeaths per year: 4,000 This includes all sorts of drownings in boat accidents and those resulting from swimming, playing in the water, falling in, or even having a bath. The human body is what, 70% water? And we begin our lives in a watery environment, there's lots of oxygen in water what's the deal? Something for the scientists to work on." http://www.soyouwanna.com/site/toptens/accidents/accidentsfull.html BAN DIHYDROGEN MONOXIDE!!! DO IT FOR THE CHILDREN!!!
DrDNA Posted February 4, 2009 Posted February 4, 2009 MATERIAL SAFETY DATA SHEET NSN: 681000N065440 Manufacturer's CAGE: 0TZV1 Part No. Indicator: A Part Number/Trade Name: WATER =========================================================================== General Information =========================================================================== .......... ........................ ....................................... =========================================================================== Ingredients/Identity Information =========================================================================== Proprietary: NO Ingredient: WATER Ingredient Sequence Number: 01 Percent: >97 NIOSH (RTECS) Number: ZC0110000 CAS Number: 7732-18-5 OSHA PEL: N/K (FP N) ACGIH TLV: N/K (FP N) =========================================================================== Physical/Chemical Characteristics =========================================================================== Appearance And Odor: CLEAR, COLORLESS LIQUID Boiling Point: 212F,100C Melting Point: 32.0F,0.0C Vapor Pressure (MM Hg/70 F): 17.5 Vapor Density (Air=1): N/A Specific Gravity: 1 (H*2O=1) Evaporation Rate And Ref: N/A Solubility In Water: COMPLETE =========================================================================== ...... .............. ............................ Health Hazard Data =========================================================================== LD50-LC50 Mixture: NONE SPECIFIED BY MANUFACTURER. Route Of Entry - Inhalation: YES Route Of Entry - Skin: YES Route Of Entry - Ingestion: YES Health Haz Acute And Chronic: ACUTE/CHRONIC: NOT APPLICABLE. Carcinogenicity - NTP: NO Carcinogenicity - IARC: NO Carcinogenicity - OSHA: NO Explanation Carcinogenicity: NOT RELEVANT. Signs/Symptoms Of Overexp: NOT APPLICABLE. Med Cond Aggravated By Exp: NONE SPECIFIED BY MANUFACTURER. Emergency/First Aid Proc: EYES: FLUSH WITH POTABLE WATER FOR AT LEAST 15 MINUTES. SEE MD (FP N). SKIN: FLUSH WITH COPIOUS AMOUNTS OF WATER. SEE MD (FP N). INHALATION: REMOVE TO FRESH AIR. SUPPORT BREATHING (GIVE OXYGEN OR ARTIFICIAL RESPIRATION) (FP N). INGESTION: CALL MD IMMEDIATELY (FP N). =========================================================================== Precautions for Safe Handling and Use =========================================================================== Steps If Matl Released/Spill: REMOVE WITH SPONGE OR MOP. Neutralizing Agent: NONE SPECIFIED BY MANUFACTURER. Waste Disposal Method: DISPOSE OF IN ACCORDANCE WITH ALL APPLICABLE LOCAL, STATE AND FEDERAL ENVIRONMENTAL REGULATIONS. Precautions-Handling/Storing: BOND AND GROUND CONTAINERS WHEN TRANSFERRING LIQUID. KEEP CONTAINERS TIGHTLY CLOSED. STORE IN A COOL, DRY, WELL- VENTILATED STORAGE AREA. Other Precautions: NONE. =========================================================================== Control Measures =========================================================================== Respiratory Protection: RESPIRATORY PROTECTION REQUIRED IF AIRBORNE CONCENTRATION EXCEEDS TLV. AT CONCENTRATIONS ABOVE 200 PPM, A NIOSH/MSHA APPROVED SCBA IS ADVISED. Ventilation: MECHANICAL (GENERAL). Protective Gloves: IMPERVIOUS GLOVES (FP N). Eye Protection: ANSI APPRVD CHEM WORKERS GOGGS (FP N). Other Protective Equipment: EMERGENCY EYEWASH & DELUGE SHOWER MEETING ANSI DESIGN CRITERIA (FP N). Work Hygienic Practices: GOOD LABORATORY PRACTICES. Suppl. Safety & Health Data: NONE SPECIFIED BY MANUFACTURER. =========================================================================== Transportation Data =========================================================================== =========================================================================== Disposal Data =========================================================================== =========================================================================== Label Data =========================================================================== Label Required: YES Technical Review Date: 25OCT95 Label Date: 25OCT95 Label Status: G Common Name: WATER Chronic Hazard: NO Signal Word: NONE Acute Health Hazard-None: X Contact Hazard-None: X Fire Hazard-None: X Reactivity Hazard-None: X Special Hazard Precautions: ACUTE/CHRONIC: NOT APPLICABLE. Protect Eye: Y Protect Skin: Y Protect Respiratory: Y
npts2020 Posted February 5, 2009 Posted February 5, 2009 OK, but it wasn't the water that was a hazard was it?What radioisotopes were you sloshing about? Not by the time I got to it. It was mainly cobalt-60 in microscopic particles in the water. Sometimes more than enough to max out a geiger detector.
hermanntrude Posted February 5, 2009 Posted February 5, 2009 a lab i worked in for some time had once been checked for radiation only to discover one fume hood was fairly heavily contaminated with tritium, and had been for years, unbeknown to the dozens of people who had worked there.
doG Posted February 5, 2009 Posted February 5, 2009 For me it's a toss up between hydrofluoric acid and ammonium perchlorate....
npts2020 Posted February 6, 2009 Posted February 6, 2009 a lab i worked in for some time had once been checked for radiation only to discover one fume hood was fairly heavily contaminated with tritium, and had been for years, unbeknown to the dozens of people who had worked there. That is far more common than most people imagine. In general, most radiation workers get lower overall doses than your average well-tanned beach bum.
jdurg Posted February 15, 2009 Posted February 15, 2009 Hydrazoic Acid (HN3); the propellant that makes air bags inflate. I have several colleagues that lost fingers to exothermic reactions that got away from them while using this stuff. No it isn't. HN3 is a liquid at room temperature and is very volatile. It would NEVER be used as an airbag inflater. You must have mean Sodium Azide (NaN3). That is a shock sensitive explosive used to inflate airbags. The downside is a small bit of sodium metal that is vaporized into the air, but that side effect is worth it for the safety that an air-bag provides. I had an airbag go off in a car accident I was in last June. Had a nasty sore throat for a few days afterwards, but my life was saved.
John Cuthber Posted February 15, 2009 Posted February 15, 2009 Sodium azide is not explosive or shock sensitive. The airbags are filled with N2 by the reaction of NaN3 with KNO3, silica and other ingredients. These mixtures are explosive. The silica is there to trap most of the sodium that is formed in the reaction by convertig it to sodium silicate. On the other hand, the stuff is roughly as toxic as cyanide and hydrazoic acid is explosive.
CharonY Posted February 18, 2009 Posted February 18, 2009 I cannot really say which of the compounds I am working was the most hazardous. But on a different note: we got a lab safety update recently and within the memo there was the info that a lab assistant at UCLA died while handling t-butyl lithium. From the report the major burns were on hands and arms and secondary to the body (due to a synthetic sweater and NO labcoat). Overall 40% burns which proved to be fatal.
DrDNA Posted February 18, 2009 Posted February 18, 2009 (edited) The energy in a hydrogen explosion, per gram-mole of hydrogen, is –59.97 kcal. The energy released per mole of hydrazoic acid can be (-128.09/-57.79) ~ 2.2 times greater than from a hydrogen explosion. http://sti.srs.gov/fulltext/tr2000443/tr2000443.html No it isn't. HN3 is a liquid at room temperature and is very volatile. ....................... That is a shock sensitive explosive used to inflate airbags. I was incorrect about the airbag being deployed by HN3. But, it is heat, not shock that causes NaN3 to decompose; giving off N2 gas (see below). The airbags are filled with N2 by the reaction of NaN3 with KNO3, silica and other ingredients. These mixtures are explosive. The silica is there to trap most of the sodium that is formed in the reaction by convertig it to sodium silicate. Not exactly. Not primarily at least.... The signal from the deceleration sensor ignites the gas-generator mixture by an electrical impulse, creating the high-temperature condition necessary for NaN3 to decompose. The nitrogen gas that is generated then fills the airbag. The purpose of the KNO3 and SiO2 is to remove the sodium metal (which is highly reactive and potentially explosive, as you recall from the Periodic Properties Experiment) by converting it to a harmless material. First, the sodium reacts with potassium nitrate (KNO3) to produce potassium oxide (K2O), sodium oxide (Na2O), and additional N2 gas. The N2 generated in this second reaction also fills the airbag, and the metal oxides react with silicon dioxide (SiO2) in a final reaction to produce silicate glass, which is harmless and stable. http://www.chemistry.wustl.edu/~edudev/LabTutorials/Airbags/airbags.html Here, another danger arises because if the NaN3 dissolves in water, it can form hydrazoic acid (HN3): NaN3 + H2O ---> HN3 + NaOH. HN3 is highly toxic, volatile (i.e., it becomes airborne easily), and explosive. http://www.chemistry.wustl.edu/~edudev/LabTutorials/Airbags/airbags.html Conclusion: We were all wrong (about at least one thing each). Edited February 18, 2009 by DrDNA
John Cuthber Posted February 18, 2009 Posted February 18, 2009 Would you care to find out what the equilibrium constant for this reaction is? NaN3 + H2O ---> HN3 + NaOH. Because my money is on it going very definitely the other way. However NaN3, water and CO2 will generate HN3 so it's not an important distinction. The electrical power that would be required to heat the hundred grams or so of NaN3 to a high enough temperature to decompose it all in the millisecond or so before the passenger hits the steering wheel would be huge. I suspect that it would be rather higher than the battery could deliver. The only way to get enough heat there fast enough is to set of a pyrotechnic charge. The reaction is, roughly speaking NaN3 +KNO3 -> N2 +K2O + Na2O (I'm not bothering to balance that) The oxides react with the silica to form a glass. The battery heats a thin wire and that sets the reaction going but once it's started it carries on and produces the gas because the mixture is damn near explosive. If the oxidant were not there to add to the vigour of the reaction, these things wouldn't work properly. A friend of mine did some research on these things. They are quite hazardous because they have a considerable amount of stored energy. This can cause problems when cars are scrapped and taken apart- the mechanics get special training to deal with this potential problem.
DrDNA Posted February 18, 2009 Posted February 18, 2009 Would you care to find out what the equilibrium constant for this reaction is?NaN3 + H2O ---> HN3 + NaOH. Heck no! Because my money is on it going very definitely the other way. As is my money. Balanced equations: 2 NaN3 —> 2 Na + 3 N2 10 Na + 2 KNO3 —> K2O + 5 Na2O + more N2 K2O + Na2O + SiO2 —> alkaline silicate An (old design) air bag is filled with sodium azide (NaN3) and mixtures of potassium nitrate (KNO3) and silicon dioxide (SiO2). To initiate the reaction, a 12 volt output signal from the airbag control computer heats a resistive wire element which starts the exothermic chemical reaction. The initial reaction (heating sodium azide) forms sodium and hot nitrogen gas which inflates the airbag. 2 NaN3 —> 2 Na + 3 N2 Sodium from the first reaction and potassium nitrate generate additional nitrogen in the secondary reaction. 10 Na + 2 KNO3 —> K2O + 5 Na2O + N2 The previous two reactions leave potassium oxide and sodium oxide, which react with silicon dioxide forming silicate "glass". K2O + Na2O + SiO2 —> alkaline silicate BTW: I believe that some newer technologies don't even use sodium azide and I agree that the presence of the oxidizer should make the initial reaction go MUCH faster, but those are the equations.
UC Posted February 18, 2009 Posted February 18, 2009 But on a different note: we got a lab safety update recently and within the memo there was the info that a lab assistant at UCLA died while handling t-butyl lithium. From the report the major burns were on hands and arms and secondary to the body (due to a synthetic sweater and NO labcoat). Overall 40% burns which proved to be fatal. I was given that article/memo when I started undergraduate research as a safety warning. Not that we are working with tBuLi (although there is some in the lab freezer). BTW: I believe that some newer technologies don't even use sodium azide and I agree that the presence of the oxidizer should make the initial reaction go MUCH faster, but those are the equations. The newer technologies use things like 5-amino-tetrazole. 5 nitrogens, 3 hydrogens, and a carbon (with a ring!!). Avoiding hot metal compound side-product is a good thing.
jdurg Posted February 19, 2009 Posted February 19, 2009 Sodium azide is not explosive or shock sensitive. The airbags are filled with N2 by the reaction of NaN3 with KNO3, silica and other ingredients. These mixtures are explosive. The silica is there to trap most of the sodium that is formed in the reaction by convertig it to sodium silicate. On the other hand, the stuff is roughly as toxic as cyanide and hydrazoic acid is explosive. Interesting. In the times I've had to play with NaN3, hitting it with a hammer or putting an electric current through it caused it to snap. Must have been impure NaN3, or friction from the hammer head hitting that made it go. With the electricity, it could have just been heat from the current that did it. Regardless, it wasn't nearly as sensitive as lead azide, but it was sensitive enough to make me respect it.
John Cuthber Posted February 19, 2009 Posted February 19, 2009 I doubt that anyone has done this for decades but the "traditional" way to produce pure nitrogen in the lab was to heat sodium azide- it decomposes smoothly at about 300C. That's close enough to the melting point of KNO3 that I suspect that the reactions are not the same as you get if you heat the materials separately. I think you would get some sort of solution reaction. What I'd really like to know is how anyone can be sure exactly what happens. After all there's the straightforward decomposition of KNO3 at about that temperature to give KNO2 and "O". How does the KNO3 know not to decompose, but to wait for a party of 5 sodium atoms to arrive to reduce it to nitrogen?
GDG Posted February 20, 2009 Posted February 20, 2009 Heres a question - has anyone ever seen any Antimony compounds, according to a book I have they rank top of the list in toxicity! Yep. My grad school advisor was Dr. Nathan Bauld (UT Austin), whose research interest at the time was making cation radicals and anion radicals. He invented a polymer doped with antimony or arsenic salts that one could use as a catalyst for diels-alder reactions. I mainly did computer modeling of cation radical cycloaddition reactions, while other members of the group did the wet chemistry. UT, at some point, had installed hoods in the chem labs that had an "overdrive" button for the fans, the idea being that if you spilled something especially nasty, you could hit the button and exhaust the hood rapidly. Unfortunately, the ductwork was not up to the overdrive throughput: if you hit the button, it would exhaust all that nasty stuff into the adjacent fume hood. OSHA discovered this, and required UT to disconnect half of the hoods. While I was there, a contractor was busily cutting huge holes (~2 ft diameter) in the ceilings and floors and installing additional ducts. One morning, we walked into the lab and discovered that the contractor had dropped a chunk of concrete on top of our explosion-proof refrigerator, and dented in the top by about 6". Dr. Bauld told the foreman that they had destroyed the integrity of the refrigerator, that it was now unsafe, and that they would have to replace it. We arrived the next morning to find the replacment: a 1950's style fridge, with a big lever handle. Dr. Bauld motioned the foreman to come over, and explained to him that this refrigerator was not explosion-proof, and that if one of his chemicals warmed up, it could blow the door off. We came in the next day, and found that the contractor had put a rubber band (about 3" wide, 1/4" thick) around the fridge, just above the handle, to keep the door on. We had to cut the band off to open the fridge. The next day was Saturday, and the contractor didn't show up. However, something went off in the fridge, and Dr. Bauld and the senior grad student spent the day in bunny suits cleaning up. On Monday, two of the construction workers got in the elevator with me when I was on my way up to the lab. They were joking about the fridge. I told them that they were lucky they hadn't dropped anything in one of the other labs: M.J.S. Dewar had labs around the corner from us, and did work for the Air Force. If they had dropped a chunk of concrete on his refrigerator, the entire building would have gone up. (Fortunately, Dr. Dewar had enough clout to exclude the contractor from his labs.) The construction workers turned white, and were silent the rest of the elevator ride. We had a real explosion-proof refrigerator by the end of the week (not from anything I said, I'm sure).
nitric Posted February 21, 2009 Posted February 21, 2009 woohoo, i have a new one to add to the list: HClO4, and some pretty HN4ClO4/HN4SO4 crystals from excess ammonium perchlorate that i added burns paper very fast(yes i did that in a safe way as i know that it can explode on contact with organics)
xopeaceoutt Posted February 24, 2009 Posted February 24, 2009 The most dangerous I've seen would be sodium hydroxide.
petebro Posted February 24, 2009 Posted February 24, 2009 The most dangerous chemical ive used is by far H2O , the most dangerous and readily available chemical known to humans , watchout for it .
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