Preparation method of sodium tetraphenylborate_Kain Industrial Additive

Background and overview[1]

Sodium tetraphenylborate C24H20BNa, relative molecular mass 342.24. Abbreviation Na-TPB. Colorless crystal, odorless, hygroscopic. Soluble in water, methanol, ethanol and acetone, slightly soluble in ether and chloroform, insoluble in petroleum ether. The aqueous solution is relatively stable when its pH value is above 5; it can be stored for several weeks without deterioration at pH 8. In acidic aqueous solution, it is easily decomposed into phenol, biphenyl and boric acid by the action of protons. To delay hydrolysis, add a little 1 mol/L NaOH to the aqueous solution to adjust the pH to 9-10, then add 1-2 mL 0.1 mol/L AlCl3 or Al(NO3)3, leave it overnight and then filter, and store the clear liquid in a brown bottle. It is derived from the interaction between phenylmagnesium bromide and sodium fluoroborate. It can also be prepared by reacting phenylmagnesium bromide with boron trifluoride and then hydrolyzing it. Sodium tetraphenylborate is an analytical reagent mainly used to measure potassium concentration in blood and can also be used to remove cesium metal.

Preparation^[2-3]

Method 1: A preparation method of sodium tetraphenylborate, including the following steps: add 10 grams of magnesium flakes, a few small grains of iodine and Heat 80 mL of anhydrous toluene, slowly add a mixture of 40 mL of chlorobenzene and 40 mL of tetrahydrofuran dropwise to maintain the reflux state, and then reflux for two hours after the dropwise addition is completed to prepare the Grignard reagent. Cool the temperature of the above reaction solution to about 30°C, slowly add 10 mL of toluene and 20 mL of boron trifluoride ether solution dropwise, and keep it warm for half an hour after the dropwise addition, and then lower the reaction solution to about 30°C. Tetraphenylmagnesium boron chloride is synthesized. Slowly pour the above reaction solution into 300 mL of ice water, then add 50 g of soda ash to the reaction solution, stir for 1 hour, let stand and separate into layers, extract the aqueous layer with 10 mL of toluene, combine the organic phases, and dehydrate and dry with 5 g of soda ash. Concentrate, cool and crystallize, filter, rinse with toluene, and finally wash with petroleum ether, and dry to obtain 21.0 grams of the sodium tetraphenylborate product of the present invention, with a content of >99.0%.

Method 2: Preparation method of a special effect reagent sodium tetraphenylborate, the steps are as follows:

1) Synthesis of phenyl magnesium bromide (Grenya reagent): 9.6 grams of magnesium, 200 ml of anhydrous ether and a small amount of iodine (0.5-2g) are used as initiators, and slowly add 60 grams of brominated benzene and For a mixture of diethyl ether (mixed in a ratio of 60 grams of brominated benzene and 120 grams of diethyl ether), use the dropping speed to control the reflux of diethyl ether. With the addition of brominated benzene, phenyl magnesium bromide begins to be generated. When the magnesium chips are consumed to When the volume is 1/3, pay attention to replenish magnesium chips in time. The content of the prepared phenylmagnesium bromide solution is generally controlled to 10%. If it is excessive, it can be diluted with ether.

2) Synthesis of sodium tetraphenylborate: The reaction is carried out in a three-necked flask equipped with a reflux condenser, dropping funnel and electric stirring. Add 210 grams of 10% phenyl magnesium bromide (Grignard reagent) into the reactor, slowly add 3 grams of trimethyl borate while stirring, control the reaction temperature below 34°C, stop stirring after the addition, and leave it for 3-4 hours. Separate layers, the upper layer is the ether layer, and the ether is recovered after separation; the lower layer is tetraphenylboron magnesium bromide and phenyl magnesium bromide, etc. Then slowly neutralize it with 10% sodium carbonate under stirring until the pH value is 8-9, then add 10 ml of water for hydrolysis, stir for 1 hour, stop stirring, place it into layers, and separate the upper layer into an ether solution of sodium tetraphenylborate. The water layer was extracted three times with diethyl ether. The extracts were combined to recover the diethyl ether. The residue was dissolved in 50 ml of water, cooled, and filtered. The filtrate was distilled under reduced pressure to remove water, and the by-product biphenyl and other impurities were removed by steam distillation under reduced pressure until it flowed out. Until the product becomes a clear solution, add a small amount of activated carbon (0.5-2g) after cooling, filter, adjust the pH value of the filtrate to 8-9, then add 20% sodium chloride to salt out, after cooling, filter and crystallize to obtain a crude product.

3) Refining: Mix the crude product with acetone, heat to dissolve, and filter; remove acetone from the filtrate until there is no acetone to obtain the finished product, which is soaked once in anhydrous ether to be a qualified finished product.

Apply^[4-6]

Sodium tetraphenylborate is an important organic precipitant. Its anions can be selected from monovalent metal ions with larger ionic radii, such as K+, Ag+, Cs+, Rb+, Tl+, Cu+, NH+4 (ammonium ions including amines and quaternary ammonium ions), forming very low solubility. White precipitate is widely used in chemical industry, medicine and health, etc., such as measuring K+ ion content in blood.

1) Determination of potassium by sodium tetraphenylborate turbidimetric method. The masking agent is an aqueous solution containing 0.01~0.04mol/l Cu2+, 0.04~0.10mol/l tartaric acid, and [H+]=5~10mol/l; a method for measuring potassium by sodium tetraphenylborate turbidity method: using the masking The agent is used to mask interfering ions such as ammonium in the solution to be tested, and an alkaline EDTA disodium salt solution is added for auxiliary masking. Finally, an alkaline sodium tetraphenylborate aqueous solution is added, and the reaction solution is shaken and the turbidity measurement is performed immediately. The determination method is simple to operate, fast and accurate, and low in cost. Its linear range meets the requirements for rapid determination and is suitable for application at grassroots and agricultural extension departments; the masking agent used is minimally harmful to the human body and the environment.

2) A method for measuring NH4+ using sodium tetraphenylborate ligand to control the catalytic activity of nanosilver surface-enhanced Raman spectroscopy, including the following steps: (1) Prepare an NH4+ standard solution system with a known concentration; (2) Prepare a blank control Solution system; (3) Calculate ΔI=I?I0; (4) Make a working curve based on the concentration relationship between ΔI and NH4+; (5) Prepare the sample solution to be tested, measure its surface-enhanced Raman peak intensity value for the I sample, and calculate ΔI sample=I sample?I0; (6) Calculate the sample to be tested based on the working curveThe concentration of NH4+ in the product. This method uses ligands to regulate the catalytic activity of nanozymes, which is simple, fast and highly sensitive.

3) A method for determining NH4+ using sodium tetraphenylborate ligand to regulate the catalytic activity of nanosilver resonance scattering spectrometry, which is characterized by including the following steps: (1) Preparing a NH4+ standard solution system of known concentration; (2) Preparing Blank control solution system that does not contain NH4+; (3) Calculate ΔI=I?I0; (4) Make a working curve using ΔI versus the concentration of NH4+; (5) Prepare the sample solution to be tested, and measure its resonance scattering peak intensity value as I Sample, calculate ΔI sample = I sample ? I0; (6) Based on the working curve of step (4), calculate the NH4+ content of the sample solution. This method uses ligands to regulate the catalytic activity of nanozymes, which is simple, fast and highly sensitive.

Main reference materials

[1] Source: Dictionary of Practical Organic Chemistry

[2] CN200610148720.8 Preparation method of sodium tetraphenylborate

[3] CN201310279640.6 Preparation method of special effect reagent sodium tetraphenylborate

[4] CN200810049676.4 A method for measuring potassium in soil using sodium tetraphenylborate turbidimetric method and its masking agent

[5] CN201710701759.6 Method for determination of NH4+ using nanosilver catalyzed surface-enhanced Raman spectroscopy

[6] CN201710702723.X A method for determining NH4+ using nanosilver catalytic resonance scattering spectroscopy