Sodium methoxide is a dangerous chemical that is corrosive and flammable. It is mainly used in the pharmaceutical industry and as a condensing agent, chemical reagent, and catalyst for edible oil treatment in organic synthesis. Soluble in methanol and ethanol, decomposes into methanol and sodium hydroxide when exposed to water, and decomposes in air above 126.6°C. Insoluble in benzene and toluene.
Sodium methoxide products come in two forms: solid and liquid. The solid is pure sodium methoxide, and the liquid is a methanol solution of sodium methoxide. The sodium methoxide content is 27.5%-31%.
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Uses of sodium methoxide
Sodium methoxide is widely used in spices, dyes and other industries. Mainly used as condensing agent and strong alkaline catalyst, as well as methoxylating agent for the preparation of vitamin B1 and A, sulfadiazine and other drugs. A small amount is used in pesticide production. It can also be used to treat edible fats and edible oils (especially Catalyst for processing lard). In addition, sodium methoxide can also be used as an analytical reagent.
Preparation method of sodium methoxide
1. Alkali production process sodium methoxide It is obtained by the reaction between methanol and sodium hydroxide. The reaction formula is as follows:
CH3OH + NaOH – CH3ONa + H2O
(1) Configuration of methanol alkali solution
Crush solid sodium hydroxide , add in proportion to the alkali-dissolving pot containing methanol (99.8%), start the liquid alkali circulation pump, control the temperature below 70°C, and dissolve the sodium hydroxide. When the content reaches 20%-23%, cool down to 40°C. , pour into the precipitation tank, let stand for 12 hours, and set aside.
(2) Preparation of sodium methoxide
Pour water vapor into the interlayer of the evaporator and reaction tower for heating, control the temperature at 85-100℃, and use 180L/ Add anhydrous methanol to the vaporizer at a flow rate of h, and at the same time, add methanol alkali liquid from the top of the reaction tower at a flow rate of 25kg/h. The methanol gas containing 2% moisture produced by the reaction is evaporated from the top of the reaction tower and enters The purification distillation tower separates the water to make anhydrous methanol for recycling. The temperature at the bottom of the reaction tower (i.e., the vaporizer) is controlled at 65-70°C. Check that the material at the bottom of the tower contains 27%-31% sodium methoxide and 1% free alkali. The product is obtained as follows, with a yield of 86% (calculated as sodium hydroxide).
The consumption quota of this process is as follows: methanol (95%) 973kg/t, sodium hydroxide (99.5%) 209kg /t.
2. Metal production process
Using metallic sodium and methanol as raw materials, an intermittent production process is used to carry out chemical reactions to produce sodium methoxide methanol solution. The reaction formula is as follows:
2CH3OH + 2Na–2CH3ONa + H2↑
This production process is mainly divided into four parts: (1) Feeding process, pump industrial methanol to the methanol metering tank, and put 120kg metallic sodium into the reaction kettle; (2) In the nitrogen replacement process, close the feeding and venting valves, introduce nitrogen into the reaction kettle, so that the pressure gauge index reaches 0.1MPa, open the venting valve to relieve the pressure, repeat it three times and then reflux, keep the venting valve open and continue to pass in nitrogen; (3) In the reaction process, pour cooling water into the condenser, and immediately add methanol through the methanol metering tank (pay attention to the methanol addition speed) to carry out the reaction. Stop feeding nitrogen after 5-10 minutes of reaction. Continue to add methanol, and 820kg of methanol will be added within 2-3 hours. After metered addition, close the methanol feeding valve and continue the reaction for 2-3 hours until no bubbles are generated in the reaction solution; (4) Blending process, add the product to the blending storage tank, take samples for analysis, blend to the required concentration, and put it into barrels.
Market Development Status
As a mature chemical product, sodium methoxide has been produced in my country for decades. The overall price is higher in the south and lower in the north. The selling price in southwest China is around 4,500 yuan per ton, and in Shandong, it is around 0 yuan per ton. At present, the domestic market has a large demand for sodium methoxide products produced by the metal sodium method. Since the sodium methoxide products produced by the metal sodium method have low free alkali content and have better catalytic activity, their market usage is on the rise.
At present, the total supply and demand of the domestic sodium methoxide market is generally balanced, but at the same time there are also the following characteristics: most sodium methoxide users who have a larger demand than red phosphorus flame retardants have their own production companies; liquid sodium methoxide Production equipment is spread all over the country, and solid sodium methoxide production equipment is relatively concentrated; for liquid sodium methoxide products, alkali and metal production processes coexist, with the majority being metal process; sodium methoxide products are produced based on sales; there is an imbalance in supply and demand in some markets Condition.
