Physical and Chemical Properties
Acetone oxime (Abbreviation DMKO for short), also known as dimethyl ketone oxime, is a white flaky crystal at room temperature, relative density: 0.9113, melting point: 60 ℃, flash point: 47.2 ℃, boiling point: 134.8 ℃, toxicity LD50: 5500mg/kg. It is soluble in water and alcohol, ether and other solvents, saturated aqueous solubility is 25% (mass percentage), its aqueous solution is neutral, it hydrolyzes easily in dilute acid, can make potassium permanganate fading at room temperature. Mainly used as chemical oxygen scavenger for industrial boiler feed water, compared with the traditional boiler chemical oxygen scavenger, it has characteristics of less dosage, high oxygen removal efficiency, non-toxic, pollution-free. It is the best drug for the outage protection and passivation treatment of subcritical boiler, also is the ideal products of substituted hydrazine and other traditional chemical oxygen scavengers in medium and high pressure boiler feed water.
Figure 1 the molecular structure of Acetone oxime.
Chemical Properties
It is white needle-like crystal. Melting point is 61 ℃, boiling point is 136 ℃, 134.8 ℃ (97.1kPa), 61 ℃ (2.67kPa), the relative density is 0.9113 (62/4 ℃), refractive index is 1.4156. Easily soluble in water, ethanol, ether and acetone, soluble in acid, easily hydrolyzed in dilute acid. It volatilize in the air quickly.
Uses
1. Acetone oxime is used in organic synthesis, as an analytical reagent, used for the determination of cobalt.
2. Used as the intermediates of Caffeine, theophylline, SMD
3. Acetone oxime is used as test reagents for Chromium, used for organic synthesis, used as novel oxygen scavenger of boiler water, intermediates of medicine, pesticide.
4. It is used as raw materials of pharmaceutical, pesticide, dyes and organic silane coupling agent, can also be used as analytical reagent to identify nickel, cobalt, etc.
chemical reaction
Acetone oxime has a strong reduction, it is easy to react with oxygen in water to reduce the dissolved oxygen content in water, reaction is as follows:
2C3H7NO + O2 → 2C3H6CO + N2O + H2O and 4 (CH3) 2C = N-OH + O2 → 4 (CH3) 2C = O + 2N2 + H2O
Meanwhile, Acetoxime also reacts with the metal for passivation, reaction is as follows:
2C3H7NO + 6Fe2O3 → 2C3H6CO + N2O + 4Fe3O4 + H2O
Acetoxime can reduce the content of iron in the feed water, to prevent overheating of the metal pipe and corrosion damage of the boiler due to the formation of iron oxide deposits, while with the cleaning effect for copper corrosion products deposited on pipes, economizer, etc. This is the reason that in the early use of acetone oxime, the content of copper in boiler water will be significantly higher.
Decomposition products of Acetoxime are mainly nitrogen and water, a small amount of formic acid, acetic acid, nitrogen oxides and so on. On the premise of ensuring oxygen removal effect, when the residual amount of DMKO in feed water is controlled to be 5~40μg/L, the formic acid, acetic acid, Cl-, SO42 + was not detected in all tested samples of water vapor, at the same time NO2-and NO3-content of same samples were tested, are also not detected. Therefore, there is no any adverse effects for the use of acetone oxime oxygen in vapor system.
Production method
It is obtained by the reaction of acetone with hydroxylamine hydrochloride. The hydroxylamine hydrochloride solution was slowly added dropwise in acetone, the reaction temperature is controlled at 40-50 ℃. The oximation reaction liquild was neutralized by 40% sodium hydroxide up to basic (pH7-8), cooling and filtration, the crude product was filtered off and add the zeolite, atmospheric distillation, cooling to obtain the finished product crystals.
Passivation agent after Boiler pickling
After the boiler pickling, the metal surface has high activity, it is necessary to use passivating agent to generate dense protective film on metal surfaces to prevent secondary corrosion of metal. Multi-hydrazine, sodium nitrite, sodium tripolyphosphate, etc, is conventionally used as passivating agent. Although the hydrazine and sodium pin Asia have a good passivation effect, but the drug itself has significant side effects to operators and users, it is difficult to handle passivation solution, and it pollutes the environment. Although Passivation method of sodium tripolyphosphate has advantages that its process is simple, liquid waste is easy to handle, but easily lead to the boiler water PH value lower after the unit started, bring some difficulties to control and process the water vapor quality. The experiment proved that replacement of the above passivating agents by acetone oxime (dimethyl ketone oxime) can obtain a satisfactory or better result. And it has the advantages of less dosage, emissions non-toxic pollution-free and so on.
General passivation parameters:
The concentration of Passivating agent: 8000-900mg/l
PH value (ammonia tone) of passivation solution: 9.50-11
The temperature of purified fluid (atmospheric pressure cleaning system): 85-90
Purification Time: 14-18h
Thermal Equipment Disable protection agent
Due to this product has a strong reduction, the solution can form a good magnetic film on the steel surface, thereby effectively delay corrosion during downtime of the thermal equipment. The solution containing acetone oxime (dimethyl ketone oxime) can be implemented in wet protection, can obtain significant inhibition effect.
concentration of Protection liquild: 350-400mg/l (water preparation)
PH:> 10.5 (ammonia adjustment)
During protection, should note:
1. Due to sampling and other reasons that result in loss of protective agents, use dosing devices regularly serviced.
2. The samples tested once a week or a half months, if the concentration of protection liquild is stable, the slow decline for the concentration of iron and oxygen is a normal phenomenon, on the contrary should pinpoint the cause.
Hazards & Safety Information
Category: Oxidant
Toxicity grading: Moderately toxic
Acute toxicity
Oral-rat LD50:> 500 mg/kg, intraperitoneal-Mouse LD50: 4000 mg/kg
Flammability hazard characteristics: In case of fire, it is combustible. Thermal decomposition releases nitrogen oxide gases.
Storage Characteristics: Treasury ventilation, low temperature drying, light loading and unloading, it is stored separately from oxidant and acid.
Extinguishing agent: foam, Carbon dioxide, dry powder, sand
Chemical Properties
White crystals
Uses
It is an intermediate used in organic synthesis and in agriculture. It is also an important raw material.
Definition
ChEBI: Acetone oxime is a ketoxime.
Safety Profile
Moderately toxic by ingestion andintraperitoneal routes. When heated to decomposition itemits toxic fumes of NOx.
Synthesis
(1)Hydroxylamine sulfate method
Obtained by the reaction between acetone and hydroxylamine sulfate. Hydroxylamine sulfate solution is slowly added dropwise to acetone, and the reaction temperature is controlled at 40~50. The oximized reaction solution is neutralized with 40% sodium hydroxide until it becomes alkaline (pH 7~8), cooled and filtered, the filtered crude product is added to zeolite, distilled at atmospheric pressure, and cooled to obtain crystalline acetone oxime.
(2)Ammonia method
Taking acetone, ammonia and hydrogen peroxide as raw materials, dissolve acetone in isopropanol according to the dosage of 100~300g solvent/mol acetone, add TS-1 catalyst according to the dosage of 3~10g catalyst/mol acetone in the above acetone solution and ammonia according to the dosage of 1.2~2mol ammonia/mol acetone to formulate the reaction solution, and then add ammonia in the reaction solution at the dosage of 50~120 and 0.1~1.0MP. Then, at 50-120C and 0.1-1.0MPa pressure, hydrogen peroxide was slowly added dropwise to the above reaction solution at a dosage of 1.0-1.3mol hydrogen peroxide/1mol acetone for 0.25-12h to obtain the acetone oxime product.
Purification Methods
It crystallises from pet ether (b 40-60o) and can be sublimed. [Beilstein 1 H 649, 1 IV 3202.]
