Chemical Properties
Yellow to yellow green liquid, a creamy fragrance after bulk dilution (1mg/kg), high vapor pressure is, evaporate quickly at room temperature, melting point-3～-4℃， boiling point 87～88℃, flash point 13℃. Soluble in ethanol, ether, most non-volatile oil and propylene glycol, soluble in glycerin and water, insoluble in mineral oil. Natural products exist in laurel oil, ajawa oil, angelica root oil, raspberry, strawberry, cream, Wine etc. Because it is volatile, it only exists in in the primary distillate and distilled water.
Uses
Diacetyl (2,3-butanedione) is a naturally occurring product and can be found in numerous foods such as butter, milk, cheese, smoked or roasted meats, breads, fruits, vegetables, coffee, beer, and wine. Diacetyl is synthesized to be used as a food additive to impart a buttery flavor and has been designated as a generally recognized as safe (GRAS) substance with low acute toxicity (FDA, 1980). Desirable flavor concentrations in food are approximately 0.05–5.0 ppm and above that range it imparts a disagreeable taste. The most recognized recent use has been in microwave popcorn, but it has also been used for many other products (NTP, 1994, 2007). Diacetyl may be used in additives as a liquid, paste, or powder (Boylstein et al., 2006).
It meets GB 2760—1996 standards of edible spices for the moment. It is mainly used for the preparation of food essence like cream, cheese fermentation and coffee typed essence,used in milk, butter, margarine, cheese, sweets and other flavors, such as berry, caramel, chocolate, coffee, cherry, vanilla bean, honey, cocoa, fruit, wine, aroma, rum, nuts, almonds, ginger and so on. It can also be used in fresh fruit fragrance essence for makeup or new type essence in trace amount, and be used as gelatin hardening agent and photographic adhesive agent.
Content analysis
The content of 2,3-Butanedione is analyzed according to method 1(hydroxylamine method) of the aldehyde and ketone analyzing methods (OT-7). The sample weight is 500mg. The equivalent factor (e) in calculation is 21.52 .It is Fit to be analyzed using nonpolar column in GT-10-4.
Toxicity
Not specified by ADI (FAO/WHO，1994)
GRAS(FEMA；FDA，§184．1278，2000)
Quantity restrictions
FEMA(mg/kg)： FEMA(mg/kg)：soft drinks 2.5；cold drinks 5.9；sweets 21；bakery products44； puddings 19；chewing gum 35；shortening 11.
Production
In nature, Diacetyl exists widely in many Plant essential oils, such as iris oil, angelica oil, laurel oil, etc. It is the main component of butter and other natural products fragrance.
In industry, methyl ethyl ketone was treated with nitrite acid to generate diacetylmonoxime. Diacetylmonoxime is then decomposed by sulfuric acid to produce Butanedione.
Diacetyl can be obtained by chemical ionization method from high content of essential oil. Two parts of phosphoric acid were added to one part of essential oil to
produce crystalline adduct CH3CO-COCH3. Butanedione was released after the addition of water. Excessive addition of phosphoric acid will lead to liquid adduct product.
Diacetyl can be obtained by special fermentation of glucose.
Diacetyl can be synthesized using methyl ethyl ketone as raw material.
Diacetyl was oxidized by sodium nitrite in the presence of hydrochloric acid,
Then, the process of istillation is carried out after hydrolysis in the presence of sulfuric acid to produce Butanedione.
Description
2,3-Butanedione, also known as Diacetyl, is a reactive diketone in artificial butter flavors. It is a water-soluble and volatile, alpha-diketone compound that has a buttery odor. Diacetyl occurs naturally in plants, fruits, coffee, honey, cocoa, and dairy products. It is a natural by-product of fermentation and is found in beer and wine. Diacetyl is also present in cigarette smoke.
Diacetyl can be synthesized by converting 2-butanone to an isonitroso compound and then hydrolyzing it with hydrochloric acid. Other methods for producing diacetyl include oxidation of 2-butanone over a copper catalyst at 300°C and dehydrogenation of 2,3-butanediol over a copper or silver catalyst. In addition, diacetyl can be synthesized through the acid catalyzed condensation of 1-hydroxyacetone and formaldehyde. Naturally occurring diacetyl is also available from starter distillate, a by-product of dairy product fermentation. Although diacetyl and starter distillates are liquids, they can be converted to a powdered form by encapsulating them within a solid material to prevent volatility. Diacetyl in powdered form is also found in flavorings that have been spray dried. The boiling point of diacetyl is 88°C with a calculated vapor pressure of 55 mmHg at 20°C.
Chemical Properties
2,3-Butanedione has a very strong buttery odor in very dilute solution. It is a constituent of many fruit and food aromas and well-known as a constituent of butter. Many methods are known for itsmanufacture, for example, dehydrogenation of 2,3-butanediol with a copper chromite catalyst. Biotechnological production on an industrial scale is referred. It is used mainly in aromas for butter and roasted notes. Large quantities are used for flavoring margarine; small amounts are used in perfumes.
Occurrence
Reported in the oils of: Finnish pine, angelica and lavender; in the flowers of Polyalthia canangioides
Boerl. var. angustifolia and Fagroea racemosa Jack. The following plants are also reported to contain diacetyl: Monodora
grandiflora Benth., Magnolia tripetale L., Ximenia aegyptiaca L., Petasites fragrans Presl., various narcissi and tulips. It has
been identified in certain types of wine, the natural aromas of raspberry and strawberry, and the oils of lavender, lavandin,
Réunion geranium, Java citronella, and Cistus ladaniferus L. It is also reported to be found in ligonberry, guava, raspberry,
strawberry, cabbage, peas, tomato, vinegar, various cheeses, yogurt, milk, butter, chicken, beef, mutton, pork, cognac, beer,
wines, whiskies, tea and coffee.
Uses
2,3-Butanedione is a flavoring agent that is a clear yellow to yellowish green liquid with a strong pungent odor. It is chemically synthesized from methyl ethyl ketone. It is miscible in water, glycerin, alcohol, and ether, and in very dilute water solution it has a typical buttery odor and flavor. It is used as Carrier of aroma of butter, vinegar, coffee, and other foods. It is also used Inactivates aminopeptidase-N, precursor to α-diones, Cyclocondensation with amines has been used to form triazine and pteridine ring systems.
Definition
ChEBI: 2,3-Butanedione is an alpha-diketone that is butane substituted by oxo groups at positions 2 and 3. It is a metabolite produced during the malolactic fermentation. It has a role as a Saccharomyces cerevisiae metabolite and an Escherichia coli metabolite.
Preparation
From methyl ethyl ketone by converting to the isonitroso compound and then decomposing to diacetyl by hydrolysis with
HCl; by fermentation of glucose via methyl acetyl carbinol.
Aroma threshold values
Detection: 0.3 to 15 ppb: recognition: 5 ppb
Taste threshold values
Taste characteristics at 50 ppm: sweet, buttery, creamy and milky.
General Description
2,3-Butanedione appears as a clear colorless liquid with a strong?chlorine-like odor. Flash point 80 °F. Less dense than?water. Vapors heavier than air.
Air & Water Reactions
Highly flammable. Soluble in water.
Reactivity Profile
2,3-Butanedione is a flammable liquid, b.p. 88° C, moderately toxic. When heated to decomposition 2,3-Butanedione emits acrid smoke and fumes [Sax, 9th ed., 1996, p. 544].
Health Hazard
Inhalation or contact with material may irritate or burn skin and eyes. Fire may produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control may cause pollution.
Fire Hazard
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.
Toxicology
Diacetyl is an intensely yellowish or greenish-yellow mobile liquid. It has a very powerful and diffusive, pungent, buttery odor and typically used in flavor compositions, including butter, milk, cream, and cheese. Diacetyl was found to be mutagenic in Ames test conducted under various different conditions with Salmonella typhimurium strains. For example, diacetyl was mutagenic by TA100 in the absence of S9 metabolic activation at doses up to 40 mM/plate. It was mutagenic in a modified Ames assay in Salmonella typhimurium strains TA100 with and without S9 activation. The acute oral LD50 of diacetyl in guinea pigs was calculated to be 990 mg/kg. The acute oral LD50 of diacetyl in male rats was calculated to be 3400 mg/kg, and in female rats, the LD50 was calculated to be 3000 mg/kg. When male and female rats were administered via gavage a daily dose of 1, 30, 90, or 540 mg/kg/day of diacetyl in water for 90 days, the high-dose produced anemia, decreased weight gain, increased water consumption, increased leukocyte count, and an increase in the relative weights of liver, kidneys, and adrenal and pituitary glands. The data for teratogenicity and carcinogenicity are not available. Although the FDA has affirmed diacetyl GRAS as a flavoring agent, low molecular weight carbonyls, such as formaldehyde, acetaldehyde, and glyoxal have been reported to possess a certain chronic toxicity.
Safety Profile
A poison by ingestion
and intraperitoneal routes. A skin irritant.
Human inhalation hazard in popcorn
manufacture. Human mutation data
reported. Flammable liquid. Dangerous fire
hazard when exposed to heat or flame. To
fight fire, use alcohol foam, CO2, dry
chemical. When heated to decomposition it
emits acrid smoke and fumes. See also
KETONES.
Potential Exposure
Tumorigen,Drug, Mutagen, Primary Irritant. Butanedione is used as anaroma carrier food additive in butter, vinegar, coffee, andother foods.
First aid
If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seekmedical attention immediately. If this chemical contactsthe skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove fromexposure, begin rescue breathing (using universal precautions,including resuscitation mask) if breathing hasstopped and CPR if heart action has stopped. Transferpromptly to a medical facility. When this chemical hasbeen swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.
Carcinogenicity
Diacetyl was tested for its ability to induce primary lung tumors in strain A/He mice. The mice received three IP injections of diacetyl per week for 8 weeks and were killed 24 weeks after the first injection. The total dose of diacetyl given was 1.7 or 8.4 g/kg. The number of lung tumors in diacetyl exposed mice was not significantly different from the control mice.
Inhalation carcinogenicity bioassays withWistar Han rats and B6C3F1 mice at exposure levels of 0, 12.5, 25, and 50 ppm are underway according to the National Toxicology Program.
Environmental Fate
Mechanisms of diacetyl-induced toxicity are not known, but some possible mechanisms of toxicity have been postulated. The adjacent carbonyl groups on diacetyl make it a reactive compound. In vitro studies have demonstrated that diacetyl can bind to arginine and inactivate proteins. The electron affinity of diacetyl suggests that it can undergo electron transfer activity, which can lead to oxidative stress by oxygen redox cycling. Redox cycling and oxidative stress may also be initiated during metabolism of diacetyl by DCXR (dicarbonyl/L-xylulose reductase). Reactive oxygen species are known to be produced from metabolic activation of dicarbonyl substrates by related carbonyl reductase enzymes in the presence of O2.
storage
Color Code—Red: Flammability Hazard: Storein a flammable liquid storage area or approved cabinetaway from ignition sources and corrosive and reactivematerials. Store in tightly closed containers in a cool,well-ventilated area. Sources of ignition, such as smokingand open flames, are prohibited where Butanedione isused, handled, or stored in a manner that could createa potential fire or explosion hazard. Metal containersinvolving the transfer of=gallons or more of butanedioneshould be grounded and bonded. Drums must be equippedwith self-closing valves, pressure vacuum bungs andflame arresters. Use only nonsparking tools and equipment,especially when opening and closing containers ofButanedione. Wherever butanedione is used, handled,manufactured, or stored, use explosion-proof electricalequipment and fittings.
Shipping
Butanedione must be labeled “FLAMMABLELIQUID.” It falls in Hazard Class 3 and Packing Group II.
Purification Methods
Dry biacetyl over anhydrous CaSO4, CaCl2 or MgSO4, then distil it in a vacuum under nitrogen, taking the middle fraction and storing it at Dry-Ice temperature in the dark (to prevent polymerization). [Beilstein 1 IV 3644.]
Toxicity evaluation
Diacetyl released to the environment is expected to be highly
mobile in soil and is not expected to adsorb to suspended sediments and solids in water. Diacetyl is degraded by
a bacterium tentatively identified as Pseudomonas. Bioconcentration
of diacetyl by aquatic organisms is not likely.
Diacetyl is expected to volatilize from soil and water surfaces,
and diacetyl is likely to exist solely as a vapor in the ambient
atmosphere. In the atmosphere, diacetyl is degraded by
photochemically produced hydroxyl radicals and it undergoes
photolysis.
Incompatibilities
Contact with oxidizers may cause fireand explosions. High heat may cause violent combustion orexplosion.
