US PAT 2004262239 - Bromine compound synthesis

mannich_depression · Wed Feb 09, 2005 1:55 pm

Some methods of Bromine Preparation are:

US Patent: US2004262239
http://l2.espacenet.com/espacenet/bnsviewer?CY=fr&LG=fr&DB=EPD&PN=US2004262239&ID=US2004262239A1+I+

Dec. 30,2004
HIGHLY CONCENTRATED BROMINE
COMPOSITIONS AND METHODS OF
PREPARATION
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention

[0002] The invention relates to liquid and solid brominecontaining
compositions, and a liquid mixed halogen bromine
and chlorine-containing composition, for use as biocides
in water treatment. The highly concentrated liquid
compositions and high-activity solid compositions have
excellent physical and chemical stability. The invention also
relates to methods of preparing the liquid and solid compositions.

[0003] 2. Description of the Related Art

[0004] There are many ways of delivering a biocidal dose
of bromine into water systems where the growth of microorganisms
must be controlled. Early examples of accomplishing
this involved introducing elemental liquid bromine
(Br,) or liquid bromine chloride (BrC1) to the water requiring
treatment. However, both liquids are very volatile and
evolve copious amounts of highly toxic and corrosive bromine
fumes under normal conditions. Therefore, elaborate
and expensive storage, transportation and handling safeguards
must be practiced when using these products. It is
hardly surprising that the high costs of managing these
hazardous properties have rendered the use of elemental
liquid bromine and liquid bromine chloride obsolete in most
water disinfection applications.

[0005] An alternative system that overcomes these limitations
employs an aqueous solution of sodium bromide
(NaBr) in conjunction with liquid sodium hypochlorite
(NaOCl) bleach. The user feeds the two materials to a
common point where the NaOCl oxidizes the bromide ion to
yield a mixture of hypobromous acid (HOBr) and hypobromite
(OBr-) ion. This activated solution must then be
quickly introduced to the water being treated because the
species in solution are unstable to the following rapid
disproportionation and decomposition reactions.
Disproportionation: 2HOBr + OBr = BrO, + 2HBr
Decomposition: 2HOBr = 0, + 2HBr

[0006] Such reactions are undesirable because the products
of the reactions (HBr, 0, and Br0,-) are not biocidally
active.

[0007] Many users of this technology indicate that metering
of two separate solutions of NaBr and NaOCl is especially
inconvenient since two sets of pumps, flowmeters,
valves, pipe work, and container dikes are necessary. In
addition, the activation system must be designed so that
sufficient time is allowed for the NaBr and NaOCl solutions
to fully react prior to being injected into the water being
treated. Another disadvantage is that NaOCl solutions deteriorate
rapidly, and so delivery pumps must continually be
readjusted to compensate and ensure that the correct proportions
of reactants are maintained for accurate dosing.
This dual NaBrNaOCl activation system is so cumbersome
and difficult to control that many users have demanded a
system in which the NaBr is supplied in a pre-activated,
one-drum form that is stabilized to disproportionation and
decomposition reactions. Clearly, a single feed liquid bromine
biocide with these properties would be far more
convenient and easier to use and control than the dual
component approach.

[0008] One of the earlier attempts to develop a single feed,
liquid bromine biocide is described in U.S. Pat. Nos. 4,886,
915 and 4,966,716 to Favstritsky, et al. An aqueous solution
containing 38% elemental bromine complexed as ethanolammonium
hydrogen perbromide was administered to the
water being treated. Subsequently, U.S. Pat. No. 5,141,652
taught the use of strong solutions of halide salts and hydrohalic
acids to form solutions of bromine chloride complexes.
However, neither technology became fully commercialized
because the problem of bromine fuming from the products
was not completely alleviated.

[0009] U.S. Pat. Nos. 5,683,654, 5,795,487, 5,942,126,
and 6,136,205 describe processes to manufacture a single
feed, liquid bromine biocide by mixing aqueous hypochlorite
solutions with bromide ion sources and then stabilizing
this reaction mixture to disproportionation and decomposition
by introduction of a stabilizing agent. Although the
resultant solutions did not evolve bromine fumes, the process
required a complex two-step reaction. In the first step,
NaBr and NaOCl solutions were mixed and sufficient time
was allowed to permit the formation of a NaOBr solution. In
the second step, this was then introduced to a solution of the
stabilizing agent maintained at 50' C. However, the main
limitation of this approach lay in the use of a NaOCl bleach
solution as the foundation of the process. When NaOCl
bleach was used as the activating agent, the concentration of
the stabilized bromine product became limited by the concentration
of NaOCl bleach that is commercially available.
In fact, despite using the highest strength grades of industrial
NaOCl bleach, the bromine content of the resulting stabilized
solutions was only about 14% as Br, (6.3% as Cl,).

[0010] Moore et al. overcame the complexity of the twostep
reaction in U.S. Pat. Nos. 6,068,861, 6,495,169, and
6,322,822 and disclosed a single vessel reaction in which
bromine or bromine chloride was added to a halogen stabilizer
solution under conditions of pH control. The available
bromine content of the resultant solutions was reported to be
at least 10% as Br, (4.4% as Cl,). However, when the
process was scaled up, as disclosed in U.S. Pat. Nos.
6,299,909,6,306,441, and 6,348,219, it was found necessary
to employ a three-reactor sequence, and an upper limit of
18% as Br, (8% as Cl,) was imposed as the highest strength
concentrate that could be made by the process. Another
drawback to the processes described by Moore et al. was the
hazardous nature of the starting reagents involved. The high
cost of transporting and handling of elemental bromine or
bromine chloride meant that commercial manufacturing of
the stabilized bromine solutions could only be accomplished
in highly specialized, dedicated plants close to sites where
bromine is recovered from naturally occurring brines. In the
U.S., the process of Moore et al. could only be practiced
economically in manufacturing plants close to the brine
fields of southern Arkansas or Michigan.

[0011] Yang et al. sought to increase the concentration of
the available bromine in the stabilized formulation, and
disclosed processes in U.S. Pat. Nos. 6,156,229, 6,423,267,
Dec. 30,2004
and 6,287,473 that also employed the use of elemental
bromine, bromine chloride, or sodium bromate. Using these
methods, liquid bromine concentrates containing 26.2% as
Br2 (11.6% as Cl,) were prepared. However, it was reported
that such solutions were physically unstable, and large
amounts of bromine-containing solids precipitated out of
solution on standing overnight. Upon filtration of the solids,
the liquid phase comprised 18.7% as Br, (8.3% as Cl,). No
information on the long-term chemical stability of the concentrates
was reported. Other efforts to prepare stabilized
liquid bromine formulations of high concentration were
disclosed in U.S. Pat. No. 6,270,722 where high strength
industrial grade sodium hypochlorite solutions and gaseous
C1, were used to oxidize sodium bromide solutions. Stabilized
liquid bromine concentrates containing up to 20.75%
as Br, (9.22% as Cl,) were reported, but no information
regarding the stability of the products to precipitation of
solids was disclosed.

There is too much good stuf here, So I will upload in a minute or two,

Wow, this is like a massive work on manufacturing bromine,

What I've Done is Ocr'd the patents, And kept the format for Easy reading HTML,

Here they are.

mannich_depression