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  1. #61
    Nikola Dulgiarov's Avatar
    Join Date
    Jul 2008
    Sevilevo, Bulgaria
    Multi Format
    Purity Test/Risk and safety assessment
    OK, so today I got some preliminary results from testing, carried out by a third party; The (anhydrous) sample I sent seems to be 96.5-97% glycin, with the balance sodium chloride (from the neutralized MCA), and sodium acetate (pH balancing agent used during synthesis). There are trace amounts of p-aminophenol (<0.1%), suggesting a proper ratio and full conversion. I'm satisfied...
    Also, in respect to the safety of the production, I sat down and assessed the safety factors in a system I use for any lab work. It's a 10-grade relative system, 0 being no immediate danger, 10 being work with chemicals like methylmercury, dioxin, extreme flammables and caustics, very high temperatures, etc. The grades are founded on standard lab protocol, i.e. no food, drinks, smoking, common sense (: . Following are the salient points:
    Fire Hazard: 2 - use of solvents for testing and cleanup, solid chemicals and their solutions are unflammable
    Vapor Toxicity: 1 - MCA and acetic acid emit light vapors, but work under a fume hood, or in a properly ventilated room keeps concentrations well bellow minimum thresholds
    Contact toxiciy: 5 - prolonged skin contact with mild alkalis and p-aminophenol can result in a persisting dermatitis, possibly promoting an allergy. Glacial acetic acid can cause chemical burns. Monochloroacetic acid is highly toxic and resorbed through the skin quickly. Nitrile gloves are a minimum requirement, along with a rubber apron over the lab coar, eye protection for splashes. Most chemicals are crystalline and handling them gives little rise to dust in the air, though a simple filter mask is appropriate.
    Reaction Procedure: 2 - no immediate hazard of runaway reaction, improper mixing can cause gas evolution and fizzing that releases a mist, improper heating of reactant mixture can cause bumping(superheating of liquid and spontaneous evaporation, resulting in liquid losses).
    Glassware Procedure and handling: 2, hot glass looks the same as cold glass, temperatures of up to 130C are required, thermal burns can result from carelessness, broken glassware can be vary sharp (and painful to say goodbye to );
    Well, if general lab rules are observed, there is no particular danger to the synthesis. The most hazardous chemical is MCA, but adhering to MSDS recommendations and common sense are sufficient to prevent exposure and harm. Disposal of the liquid waste,provided that synthesis is carried out to completion, should present no problems, as all the MCA is converted, and in solutio remain NaCl and CH3COONa.
    If general lab procedures are followed, there is

  2. #62
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Rochester, NY
    Multi Format
    Good job so far.


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