Preparation method of physical and chemical properties of 2,2-bromocyanoacetamide (DBNPA)

2,2-Bromocyanoacetamide (DBNPA)

[Alias] 2,2-Dibromo-3-nitrilopropionamide

[Structural formula]

[Physical and chemical properties] White crystals, melting point 125℃

[Preparation method] There are many ways to synthesize DBNPA, you can use chloroacetic acid , cyanoacetic acid, dialkylamino acrolein, amino acetal diol or methyl cyanoacetate as raw materials, first prepare cyanoacetamide, and then bromination Get DBNPA

(1) Preparation of cyanoacetamide

Cyanoacetamide is an intermediate for the synthesis of DBNPA, and its synthesis methods are mainly as follows

①Using chloroacetic acid as raw material, first neutralize chloroacetic acid with sodium carbonate or NaOH to prepare sodium chloroacetate ; then react with NaCN in butanol solution and acidify with concentrated hydrochloric acid to obtain cyanoacetic acid; esterify cyanoacetic acid with methanol The reaction produces methyl cyanoacetate; and then it is made into cyanoacetamide by ammonolysis

② Using cyanoacetic acid as a raw material, the cyanoacetic acid is esterified with methanol or ethanol to produce methyl cyanoacetate, which is then made into cyanoacetamide through ammonialysis

③Use methyl cyanoacetate as raw material to directly react methyl cyanoacetate with ammonia to produce cyanoacetamide

(2) Synthesis of dibromonitrilopropionyl

DBNPA can be obtained by reacting cyanoacetamide with an oxidizing agent (such as Br ₂ )

Scholars at home and abroad have concluded through a large number of experiments: direct bromination has extremely low yield

Based on the results of previous studies, Joshua analyzed the advantages and disadvantages of NaBrO ₃ , KBrO ₃ , NaClO ₃ , KClO ₃ , and H ₂ O ₂ as oxidants.

Using cyanoacetamide (CAA), H ₂ O ₂ and Br ₂ as raw materials, the reaction was stirred in a reactor with an overflow discharge pipe, and the reaction temperature was controlled at (88±1)°C.

Table 7-13 Operating conditions for continuous preparation of DBNPA

Table 7-14 Product Analysis

Li Jianping from Wuhan Institute of Technology also compared different oxidants.

Weigh 2.

[Application] DBNPA is a new type of high-efficiency bactericidal and algae-killing agent and water treatment agent.
It has the advantages of high efficiency, broad spectrum, easy degradation, no residual poison, and no pollution to the environment
.

(1) Water treatment, sterilization and algae removal

A certain Sinopec plant uses DBNPA as a fungicide.
The circulating water volume of the system is about 10080m ³ /h, the system water volume is 5500m ³ , and the pH is 8.
5～9.
0
.
Field tests show that: DBNPA has a good bactericidal effect and a faster killing speed.
Adding 100mg/L of DBNPA will have a bactericidal rate of 99.
9% after 2 hours and 98.
64% after 24 hours; it has a good peeling effect on slime.
After 1 hour of DBNPA, the turbidity of the cooling water increases significantly; it is compatible with other water treatment agents and has little corrosion to the system
.

According to the Dearborn Chemical Company of the United States, a large-scale syrup manufacturing plant has experienced serious microbial contamination problems, especially the cooling tower’s packing was covered with dirt, and fibrous sludge clumps were also filled with the packing.
The operating efficiency of the cooling tower is greatly reduced.
The use of 15mg/L, 20% dibromoine aminopropionamide can not only control the microorganisms within one month, but also strip off the slimy clumps that were originally filled with fillers.
, The cooling efficiency of the cooling tower is restored
.

(2) As an antiseptic and antifungal agent

DBNPA can be used not only as a fungicide and detackifier, but also as an antiseptic and antifungal agent in metal processing lubricants, water emulsions, pulp and wood, coatings, plywood and other raw materials and products, with excellent effects
.

Related Links: Preparation and Application of Dibromohydantoin (DBDMH)