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Method for preparing highly pure aqueous hydroxylamine solutions

A pure hydroxylamine and aqueous solution technology, applied in the fields of hydroxylamine, inorganic chemistry, distillation and separation, etc., can solve the problems of high price and difficult preparation of hydroxylamine aqueous solution, and achieve the effect of greatly increasing the operation safety

Inactive Publication Date: 2003-07-02
BASF AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Accordingly, electronic-grade purity, salt-free aqueous solutions of hydroxylamine are very difficult to prepare, are therefore expensive, and are of limited use only for economical reasons

Method used

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  • Method for preparing highly pure aqueous hydroxylamine solutions
  • Method for preparing highly pure aqueous hydroxylamine solutions
  • Method for preparing highly pure aqueous hydroxylamine solutions

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] 1600 g / h of a 3.2% strength by weight, substantially salt-free, stabilized aqueous hydroxylamine solution 2 was fed into a glass bubbler tray column 1 with a diameter of 50 mm and 30 bubbler trays, the feed inlet being on plate 8. The column was operated at 300 mbar. Take a small amount of the same stabilizer that has been dissolved in the hydroxylamine solution, and meter it into column 1 on the No. 30 plate at the top. Water 8 is distilled from the top of tower 1, and the reflux ratio is 0.5. The distillate still contained 0.06% by weight residual hydroxylamine. Approximately 70 ml / h of a 50% strength by weight hydroxylamine solution 6 is pumped off from the bottom of the column. The bottom discharge contained up to 45 ppm sodium sulfate. Below the No. 1 plate at the bottom of the tower, there is also a transfer area leading to the side condenser 13. The back pressure generated by the pressure loss of the sieve plate in the tower causes the steam to be forced to b...

Embodiment 2

[0048] A hydroxylamine solution with a concentration of about 10% by weight was concentrated to 50% by weight in a 5-meter-high, 0.3-meter-diameter glass bubbler tray at about 77° C. and 0.3 bar. The steam is removed from the bottom of the tower through the PTFE pipe, and sent to the side storage container 51 with double jacket cooling device. Part of the vapor condenses here. The uncondensed vapor returns to the fifth plate of the tower through the PTFE pipeline. The amount of steam is manually limited with a throttle valve. The vapor condensed in the cooling storage tank was concentrated again to 50% by weight (high purity product).

[0049] The obtained hydroxylamine solution (both 50% by weight) has the following composition (metal content is in mg / kg: analytical precision: 0.1 mg / kg):

[0050] Standard product High purity product

[0051] (without side stream production) (with side stream production) boron 3.0 <0.1 sodium 9.0 <0.1 potassi...

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Abstract

The invention relates to a method for the production of highly pure aqueous solution from free hydroxylamine, wherein the diluted aqueous hydroxylamine solution is concentrated in a column, the vapor containing hydroxylamine is removed from the bottom of the column via a side-stream and highly pure hydroxylamine is obtained through condensation of the vapors. The inventive method is simple and mild, can be used in large-scale production and yields ''electronic grade'' hydroxylamine.

Description

technical field [0001] The present invention relates to a process for the preparation of high purity aqueous solutions of free hydroxylamine. Background technique [0002] High-purity concentrated hydroxylamine aqueous solutions are used in a wide range of applications, especially in the electronics industry, for example in combination with other substances for the initial cleaning of circuit boards. In terms of use in the electronics industry, the concentration of impurities, especially the concentration of metal ions, must be much lower than 1ppm, that is, electronic grade products must be used. However, the currently commercially available aqueous hydroxylamine solution contains impurities in the ppm range, such as sodium sulfate and other metal compounds, from the beginning of production. [0003] Hydroxylamine is produced industrially on a large scale in the form of the hydroxylammonium salt, generally in the form of hydroxylammonium sulfate. However, it is usually ne...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D3/00C01B21/14
CPCC01B21/1445C01B21/1463C01B21/1481C01B21/14
Inventor O·瓦辰博格H·舍林P·普法布E·施特勒菲尔
Owner BASF AG
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