interfere with heat transfer, plug pumps, orifices, etc. and may cause significant cyanide loss. Again, high pH values give low HCN concentration and reduce the tendency for polymer formation.

Cyanide also reacts with water to form ammonia and formate ions. In the acid pH range, hydrolysis products are formic acid and ammonium salts. Alkaline solutions produce formate salts and volatile ammonia. With strong solutions, the volume of ammonia evolved can cause dangerous pressure build-up. One gallon of 30% sodium cyanide solution can produce more than 25 ft3 of ammonia. For this reason, extra vent capacity is recommended for storage tanks.

Ordinarily the reaction between cyanide and water proceeds slowly. However, the reaction rate increases exponentially with an increase in temperature, having a critical range around 60-70 C (140-158 F). At temperatures below this range, the reaction can be controlled by cooling and, where practical, by dilution. At higher temperatures, however, the reaction can be uncontrollable and may proceed until substantially all the cyanide has been consumed. For this reason, temperature control and adequate cooling and venting capacity are needed. Sodium cyanide solution storage tanks should be equipped with facilities for measuring and controlling the temperature of the solution (see EQUIPMENT, page 17). Heating may be needed to assist in dissolving the NaCN (see Figure 1) and to prevent freezing (see Figure 5). Cooling helps to minimize cyanide loss in hot weather (see Figure 4) and could be critically important if the hydrolysis reaction begins to generate heat faster than it can be dissipated to the surroundings.

All the reactions discussed above consume a portion of the stored cyanide, and all are inhibited by maintaining low solution temperature and high pH.

If special precautions are taken, acidification of sodium cyanide to produce HCN gas for a chemical reaction is an acceptable procedure; but only when handled by technically qualified people, and after detailed planning. CAUTION: The accumulation and storage of liquid or gaseous HCN should not be considered until its properties and the required safety precautions for handling it have been studied carefully. In addition to toxicity considerations, violent exothermic polymerization reactions can occur with HCN even in the absence of air or oxygen. Other Reactions

Mild oxidants, such as alkaline hypochlorite solutions, hydrogen peroxide solutions, and permanganate solutions can oxidize cyanide to sodium cyanate. The reaction finds wide use in the control of cyanides in effluents. These oxidation reactions must be done in dilute solutions to avoid formation of highly toxic gases. (See "Waste Disposal".)

Also a Du Pont product

*See WASTE DISPOSAL on page 18.

NOTE The % NaOH shown above is the concentration in the final solution The NaCN (as shipped-containing 0.1% NaOH), when diluted to a 30% solution, will have only 0 03% NaOH in the final solution unless additional NaOH is added (Decomposition rates based on Du Pont experimental data using 35% NaCN solution.)

Strong oxidants, such as nitrates, nitrites, and chlorates react violently when added to molten sodium cyanide (or vice versa).

With the exception of lead and platinum, most metals (when finely divided) dissolve in aqueous sodium cyanide in the presence of oxygen.

Alkaline solutions of sodium cyanide dissolve waterinsoluble cuprous cyanide and zinc cyanide with formation of sodium tricyanocuprate and sodium tetracyanozincate, respectively.

Reacting an alkyl halide, sulfate, or toluene-sulfonate (p-CH3C8H4SO2OR) with sodium cyanide in aqueous alcohol, DMF, or similar aprotic solvent leads to an alkyl cyanide (nitrile). Fusing a sodium aryl sulfonate with sodium cyanide yields the aryl nitrile; for example. sodium benzene-sulfonate (sodium phenyl sulfonate) gives benzonitrile (phenyl cyanide).

*See "Manual of Hazardous Chemical Reactions. NFPA No 491 M-1975 published by the National Fire Protection Assn., 470 Atlantic Ave Boston MA 02210.

Freezing Point, F

Hydrogen cyanide, generated by reacting an acid with sodium cyanide, is capable of adding to isolated double .. bonds and to the carbonyl group of an aldehyde or ketone. In the case of acetophenone, for example, the corresponding cyanohydrin forms which hydrolyzes to atrolactic acid [a-phenyllactic acid, CeHs(CH3)C(OH) COOHJ. Similarly, when preparing an a-amino acid from an aldehyde or ketone by Strecker synthesis, the hydrogen cyanide and ammonia needed can come from ammonium cyanide formed in the reaction of sodium cyanide with ammonium chloride.

One method of synthesizing the sodium salt of ethylenediaminetetraacetic acid (tetrasodium EDTA, a chelating agent) combines ethylenediamine with formaldehyde and sodium cyanide in hot (175 F, 80 C) alkaline solution.

•Also a Du Pont product

"E. L. Elial and J. P. Freeman, Organic Syntheses, Wiley, New York, Coll. Vol. 4, 58-62 (1963)

PERSONAL SAFETY, FIRST AID AND MEDICAL TREATMENT

HEALTH HAZARDS

Because of the toxicity of sodium cyanide, all persons working with it should be completely familiar with and observe the established safety practices.

Sodium cyanide is a rapidly fatal poison when taken internally. Poisoning may occur if sodium cyanide dust is inhaled. Prolonged contact with the skin may cause irritation and possibly poisoning, particularly if there are open wounds or skin abrasions. Sodium cyanide is alkaline and causes eye burns.

5

Freezing Point, C

5

-10

-15

-20

-25

- 30

-35

45

SODIUM CYANIDE IN CONTACT WITH ACIDS OR WEAK ALKALIES LIBERATES HIGHLY TOXIC AND FLAMMABLE HYDROCYANIC ACID (HCN) GAS. ALSO, TOXIC AMOUNTS OF HCN CAN BE LIBERATED FROM WATER SOLUTIONS OF SODIUM CYANIDE (SEE PP 4-5).

The U.S. Department of Labor (OSHA) has ruled that an employee's exposure to cyanide in any eight-hour workshift of a 40-hour week shall not exceed a timeweighted average of 5 mg of cyanide (calculated as CN) per cubic meter of air. It also cautions that since cyanide may penetrate the skin, especially if broken, control of vapor or dust inhalation alone may not be sufficient to prevent absorption of an excessive dose (Title 29 CFR 1910.1000 Air Contaminants).

SAFETY PRECAUTIONS

The Basic Safety Precautions are:

1. Do not breathe dust or gas. Wear an approved dust respirator when there is danger of inhaling cyanide dust. The respirator should be one approved by the Mining Enforcement and Safety Administration or by the National Institute for Occupational Safety and Health (NIOSH). See pp. 5-7 of NIOSH's Recommended Standard for Occupational Exposure of Hydrogen Cyanide and Cyanide Salts, 1977 (No. 757-009/22).

2. Avoid skin contact with cyanides. Never permit contact with open wounds or skin abrasions. Wear protective gloves when handling solid cyanides. Wear rubber gloves when handling cyanide solutions. Wash hands and gloves thoroughly with running water after handling cyanides.

3. Do not get in eyes. Wear approved chemical splash goggles when handling cyanide solutions and when there is danger of splashing.

4. Immediately sweep up any spilled cyanide and place in a suitable container. Treat contaminated area with dilute hypochlorite solution to destroy the cyanide. Flush area with water; comply with Federal, State or local regulations. If approved, drain to neutral chemical waste sewer.

5. Take every precaution to keep acids or weak alkalies from contacting sodium cyanide. Do not store with acids or weak alkalies.

6. Do not eat, drink, or smoke in areas where cyanide is present. Do not handle or store food or beverages in cyanide areas.

7. Store sodium cyanide in a dry, well-ventilated area. Containers should be kept closed and their contents dry.

45-54 ppm

20-40 ppm 10 ppm

2-5 ppm

Tolerated for 2 to 1 hour without
immediate or delayed effects
Slight symptoms after several hours
Threshold Limit/Time-Weighted Average
for a normal 8-hour workday
Odor threshold

These numbers should be considered reasonable estimates, not exact data, and are more conservative than some literature references. Variations will exist with different people. The "rapidly fatal" exposure level of 300 ppm assumes no first aid or medical treatment has been given. Prompt administration of these recovery techniques has proven very effective. Emphasis must be placed on quick action, however.

In case of overexposure to HCN, quick action is required to sound the alarm, remove the victim from the contaminated area and provide treatment. With prompt treatment, recovery is usually rapid and complete with no after-effects. Unlike many poisons, cyanide is not cumulative in body organs. While cyanide poisoning is rapidly fatal, no case should be considered hopeless; as long as there is a heartbeat, treatment should be continued. (Only a physician can certify death).

FIRST AID AND MEDICAL TREATMENT
A. Introduction

The following points are important:

1. The treatment of cyanide poisoning is divided into two parts-First Aid and Medical Treatment. First Aid is the prompt action taken to prevent further harm or death and to put the victim in the best condition for later treatment, if needed. First Aid is

*NIOSH Criteria Document. Hydrogen Cyanide and Cyanide Salts (1976).

generally given by the layman before a doctor arrives. Medical Treatment is administered by the physician.

2. A key to treatment of cyanide poisoning is the rapid administration of antidotes and oxygen. Always have on hand a supply of the materials listed in Sections B and C below for immediate use.

3. Actions to be taken in case of exposure should be studied and planned before beginning work with cyanides.

4. In case of cyanide contact, start treatment immediately. Call a physician.

B. First Aid Supplies

First aid supplies should be located in the cyanide area, and immediately accessible at all times. They should be inspected at least twice a week by the individuals who would be using them in an emergency. The following items are required:

1. Two boxes (2 dozen) of amyl nitrite pearls. CAUTION: UNSTABLE. REPLACE EVERY 1-2 YEARS. Store in cool, dark location.

2. Oxygen resuscitators. The Flynn Series III resuscitator, from O-TWO Systems, has performed satisfactorily since it is light weight, rugged, and easy to use. For information, contact Mid-South Oxygen Company, Memphis, TN (901) 396-5058, or O-TWO Systems of Canada, Mississauga, Ontario, (416) 677-9410. A good practice is to keep six amyl nitrite pearls in each resuscitator box.

3. Two 1-pint bottles of 1% sodium thiosulfate solution.

4. A set of instructions on First Aid Treatment.

C. Medical Supplies

(For Use Only By A Physician)

A "Medical Supplies Kit" containing the following supplies, should be conveniently located outside the cyanide area, and checked at regular intervals by a responsible person.

1. Two boxes (2 dozen) of amyl nitrite pearls. CAUTION: UNSTABLE. REPLACE EVERY 1-2 YEARS. Store in cool, dark location.

2. Two sterile ampules of sodium nitrite solution (10 mL of a 3% solution in each).

3. Two sterile ampules of sodium thiosulfate solution (50 mL of a 25% solution in each).

4. Two 1-pint bottles of 1% sodium thiosulfate solution. 5. One 10 mL sterile syringe. One 50 mL sterile syringe. Two sterile intravenous needles. One tourniquet.

6. One stomach tube.

7. One dozen gauze pads.

8. A set of instructions on Medical Treatment.

D. First Aid-Directions for Giving Antidote 1. If Patient Is Conscious and Breathing

For inhalation and/or absorption, if the victim is conscious, oxygen may be all that is needed. But if victim is not fully conscious or shows signs of poisoning, follow procedure in 2 below.

2. If Patient Is Unconscious But Breathing Break an amyl nitrite pearl in a cloth and hold lightly under the patient's nose for 15 seconds, repeating 5 times at about 15-second intervals. If necessary, repeat this procedure every 3 minutes with fresh pearls until 3 or 4 pearls have been given. Give oxygen from a resuscitator to aid recovery.

3. If Patient Has Stopped Breathing

Use oxygen resuscitator (preferably) or give artificial respiration until breathing starts. Also break an amyl nitrite pearl" in a cloth and hold lightly under the patient's nose for 15 seconds, repeating 5 times at about 15-second intervals. If necessary, repeat this procedure every 3 minutes with fresh pearls until 3 or 4.pearls have been given. When giving amyl nitrite to a victim not breathing, place the broken pearl under the resuscitator face-piece in such a way that it will not enter the mouth and choke the victim. A clip is helpful to hold the pearl.

E. First Aid-Inhalation Of Cyanide

Carry patient to fresh air. Have patient lie down. Administer antidote and oxygen (Section D) and remove contaminated clothing. Keep patient quiet and warm until physician arrives.

F. First Aid-Ingestion Of Cyanide

Administer antidote (Section D), then give patient one pint of 1% sodium thiosulfate solution (or plain or soapy water) by mouth and induce vomiting with finger in throat. Repeat until vomit fluid is clear. Never give anything by mouth to an unconscious person. Use amyl nitrite or Medical Treatment procedures to aid detoxification from ingested cyanide.

G.First Aid-Skin Or Eye Contact

In case of skin contact with cyanide, immediately wash with plenty of water. For eye contact flush eyes with water for at least 15 minutes and see a physician.

"WARNING: Since amyl nitrite is flammable, be careful to remove all sources of ignition, such as open flames or cigarettes, before breaking the pearts, especially with simultaneous administration of oxygen.

Any person giving first aid should be careful to keep the broken pearls away from his own mouth and nose; otherwise he may inhale sufficient amyl nitrite to become dizzy and be incompetent to give proper assistance.

H. Medical Treatment

1. Treatment of Cyanide Poisoning

While preparations for sodium nitrite and sodium thiosulfate injections are being made, break an amyl nitrite pearl" in a cloth and hold it lightly under the patient's nose for 15 seconds, repeating 5 times at about 15-second intervals. If victim is not breathing, use oxygen resuscitator or artificial respiration.

Discontinue administration of amyl nitrite and inject the solution of sodium nitrite (10 mL of a 3% solution) intravenously at the rate of 2.5 mL/ minute, then immediately inject the sodium thiosulfate (50 mL of a 25% solution) at the same rate, taking care to avoid extravasation.

Watch patient continuously for 24-48 hours if cyanide exposure was severe. If there is any return of symptoms during this period, repeat the treatment, but use one-half the amounts of sodium nitrite and sodium thiosulfate solutions.

If signs of excessive methemoglobinemia develop (i.e., blue skin and mucous membranes, vomiting, shock and coma), 1% methylene blue solution should be given intravenously. A total dose of 1 to 2 mg/kg of body weight should be administered over a period of five to ten minutes and should be repeated in one hour if necessary. In addition, oxygen inhalation will be helpful and transfusion of whole fresh blood may be considered if there has been mechanical injury with bleeding or internal blood loss simultaneously with the cyanide exposure.

NOTE: A second injection of the antidotes on one-half the dosage initially used can be administered two hours after the initial treatment to help the patient ward off a relapse.

2. Treatment of Cyanide Sores

Should sores or skin irritation develop coincidentally with handling cyanide or its solutions, consult a physician or dermatologist.

3. Treatment Of Burns

Burns from molten cyanide mixtures are the same as those from alkalies and should be treated in a similar manner. Wash the burns thoroughly with warm water to remove all cyanide and alkalies present, then treat as any burn and consult a physician.

'See page 8

PACKAGES

Du Pont sodium cyanide in the form of briquettes (CYANOBRIK), granular (CYANOGRAN®) and granular compounding grade is available in nonreturnable 100-lb net (108-lb gross) and 200-lb net (218-lb gross) steel drums. The 100-lb (45.4-kg) drums are shipped palletized 18 to a pallet and the 200-lb (90.7-kg) drums e 8 or 10 to a pallet. The drums can be stored 6 high in a warehouse CYANOBRIK is also available in 3000-lb net (3550-lb gross) FLO-BIN® containers, 24 to 44 bins per rail car or 12 bins per trailer truck.

Customers using sodium cyanide as a water solution can receive it dry in "Wet-Flo" tank cars (55 000 to 65 000 lb) and tank trucks (35 000 lb). The tank cars and trucks are unloaded by circulating premeasured water from a storage tank to dissolve the NaCN.

Drum shipments can be by ocean, rail freight or truck. Sodium cyanide is not mailable. The Department of Transportation (DOT) hazard classification is Poison B. A DOT Poison label is required. Truckloads, carloads and tank cars must carry "Poison" placards.

Due to changing government regulations, such as those of the Department of Transportation, Department of Labor, U.S. Environmental Protection Agency and the Food and Drug Administration, references herein to government regulations may be superseded. You should consult and follow the current government regulations, such as Hazard Classification, Labeling, Food Use Clearances, Worker Exposure Limitations and Waste Disposal Procedures for the up-to-date requirements for the products described in this literature.

TRANSPORTATION EMERGENCIES

If a shipment of Du Pont sodium cyanide is involved in an accident or emergency anywhere in the continental United States, make a toll-free call to the Chemical