Process for preparing chlorohydrins

A process for hypochlorinating unsaturated alpha-olefins to produce chlorohydrins which comprises forming a microemulsion of water and an unsaturated alpha-olefin and then adding an oxidant to the microemulsion under conditions sufficient to form the chlorohydrins. The microemulsion is formed by adding a non-nucleophilic surfactant and, optionally, a co-surfactant, to the mixture of water and unsaturated alpha-olefin.

BACKGROUND OF THE INVENTION 
This invention relates to the preparation of chlorohydrins. More 
particularly, this invention relates to the preparation of chlorohydrins 
by hypochlorination of alpha-olefins. The chlorohydrins are useful as 
intermediates in the preparation of epoxides. 
Conventional hypochlorination technology involves the reaction of chlorine 
with an alpha-olefin in water to yield the corresponding chlorohydrin. 
This reaction results in the formation of an excess oil phase due to the 
incompatibility of olefin with water or due to the formation of 
water-insoluble by-products. This oil phase is thought to serve as a locus 
for the production of undesired by-products such as dichlorides and 
ethers. To compensate for the incompatibility of olefin or by-products 
with water and reduce the formation of excess oil, large amounts of water 
relative to the olefin and intense mechanical mixing are used. This 
practice, however, causes in the subsequent dehydrochlorination of the 
chlorohydrin, the formation of significant volume of aqueous effluents 
containing organic impurities, the purification of which requires 
expensive treatments. 
U.S. Pat. No. 5,146,011 describes a process for preparing chlorohydrins by 
reacting a concentrated, aqueous solution of hypochlorous acid with an 
unsaturated organic compound having from 2 to about 10 carbon atoms and 
selected from the group consisting of substituted and unsubstituted 
olefins and cyclic olefins. The process is optionally carried out in the 
presence of a surfactant such as nonylphenol ethoxylate, 
alkyldimethylbenzylammonium chloride and sodium dodecylbenzenesulfate, all 
of which contain an aromatic ring. It is known that any surfactant which 
contains an aromatic ring is subject to rapid oxidative reaction with 
chlorine or HOCl in the reaction mixture. The reaction is at temperatures 
from the freezing point of water up to 55.degree. C. The low reaction 
temperature requires use of heat exchange equipment to remove the heat of 
reaction. The process requires the use of high concentration (greater than 
10 weight percent, preferably from 20 to 65, most preferabl y from 35 to 
55 percent by weight) HOCl solutions. 
British Patent Application 2 029 821 A describes a process for preparing 
glycerol dichlorohydrins by reacting chlorine and an emulsion of allyl 
chloride in water. The process requires the preparation of an emulsion of 
allyl chloride in water using a static mixer prior to feeding the emulsion 
to the reactor. To facilitate the formation of the allyl chloride-water 
emulsion, an emulsifier, such as a non-ionic or anionic emulsifier, is 
added to the allyl chloride-water mixture. In this process the reaction 
between the allyl chloride-water emulsion and chlorine takes place in the 
oily phase which produces undesirable by-products. 
It would be desirable to provide a process for preparing chlorohydrins 
which do not have the disadvantages of the known processes described 
above. 
SUMMARY OF THE INVENTION 
In a first aspect, this invention is a process for hypochlorinating 
unsaturated alpha-olefins to produce chlorohydrins which comprises forming 
a microemulsion of water and an unsaturated alpha-olefin and then adding 
an oxidant to the microemulsion under conditions sufficient to form the 
chlorohydrin. 
DETAILED DESCRIPTION OF THE INVENTION 
In general, the process for hypochlorinating unsaturated alpha-olefins to 
produce chlorohydrins comprises forming a microemulsion of water and an 
unsaturated alpha-olefin and then adding an oxidant to the microemulsion 
under conditions sufficient to form the chlorohydrins. The resulting 
microemulsion also comprises water-insoluble reaction by-products. 
Microemulsions are optically isotropic, transparent or translucent, and 
thermodynamically stable dispersions of two immiscible liquids stabilized 
by a combination of nonionic amphipatic surface active materials and 
long-chain alcohols or amines. Their properties are time independent. They 
are independent of the order of mixing, and they return to their original 
state when subjected to a small disturbance which is subsequently relaxed. 
On the other hand, emulsions are thermodynamically unstable. The drops of 
dispersed phase are generally large, perhaps larger than 0.1 .mu.m, so 
that emulsions often take on a milky rather than the transparent or 
translucent appearance generally associated with microemulsions. The 
average drop size of emulsions grows continuously with time, which is a 
manifestation of thermodynamic instability. When exposed to a body force 
proportional to the mass, such as a gravitational field, emulsions will 
ultimately separate into two distinct phases. 
The formation of an emulsion involves an increase in the interfacial area 
between two immiscible phases and is accompanied by an increase in free 
energy. For the formation of a microemulsion, the interfacial tension has 
to be lowered to very low values, which is done by adsorption at the 
interface of a surface active material. For emulsions, no such interfacial 
tension lowering is needed to form the emulsions. Although not intended to 
be bound by theory, it is believed that when the interfacial tension is 
lowered to near zero, the system emulsifies spontaneously, creating a 
microemulsion. Microemulsions are described in "Microemulsions And Related 
Systems", 1988, Bourell & Schecter, Marcel Dekker Inc, New York and U.S. 
Pat. No. 5,597,792. 
In general, the microemulsion is prepared by mixing water and an 
unsaturated alpha-olefin and then adding to the mixture a surfactant which 
is capable of forming a microemulsion of the olefin in water in the 
presence of the reaction products. The microemulsion of water and 
unsaturated alpha-olefin is spontaneously formed upon the addition of the 
surfactant to the water and olefin mixture. Preferably, the surfactant is 
combined with a co-surfactant. Preferably, the reaction product (e.g. a 
chlorohydrin) is used as the co-surfactant. Optionally, additional 
co-surfactants may be added to enhance formation of the microemulsion. The 
surfactant may be dissolved (premixed) in either the starting olefinic 
substrate or the water, depending on the solubility characteristics of the 
specific surfactant utilized. While emulsified particles typically do not 
have dynamic interface and exchange with other particles, microemulsified 
oil has very rapidly exchanging oil phase(s) and dynamic interface which 
greatly facilitate phase transfer and interfacial kinetics, both of which 
are desirable and necessary for improved chlorohydrin selectivity. 
The unsaturated alpha-olefins which can be employed in the practice of the 
present invention for preparing the chlorohydrins include unsaturated 
organic compounds containing from 2 to about 24 carbon atoms and selected 
from the group consisting of substituted and unsubstituted olefins, 
diolefins and cyclic olefins, wherein the substituent(s) is alkyl, phenyl, 
or alkylphenyl. Examples of these olefins are 1-pentene, 1-octene, 
1dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene, 2-hexene, 4-decene, 
5-dodecene, 7-tetradecene,and 9-eicosene. Mixtures of these olefins can 
also be hypochlorinated to form chlorohydrins. The bis allyl ethers can 
also be employed in the practice of the present invention. 
The surfactants which can be employed in the practice of the present 
invention for preparing the chlorohydrins are preferably non-nucleophilic. 
The term "non-nucleophilic" as used herein, refers to surfactants which do 
not readily react with chloronium ion, the key reactive intermediate 
formed by reaction of chlorine with olefin. Additionally, the surfactant 
should not readily react with chlorine. 
The non-nucleophilic surfactants which can be employed in the practice of 
the present invention for preparing the chlorohydrins include alpha-olefin 
in sulfonates, such as those prepared from 1-octene up through C.sub.20 to 
C.sub.24 alpha-olefin (see I Yamane, O. Okumura; "Surfactants: AOS" in 
Alpha Olefins Applications Handbook, G. R. Lapin and J. D. Sauer Ed.; 
Marcel Dekker, New York, NY, 1989, pp. 201-239); quaternary amines, and 
alpha-olefin in carboxylates. 
The quaternary amines which can be employed in the practice of the present 
invention include dodecyltrimethyl ammonium chloride, octadecyl trimethyl 
ammonium chloride, octadecyl pyridium chloride, didodecyldimethyl ammonium 
chloride, tallow ammonium chloride and 1-benzyl-2-hexadecyl ammonium 
chloride. 
Other surfactants which can be employed in the practice of the present 
invention include alkyl sulfonates, alkyl sulfates, dialkyl 
sulfosuccinates, fatty acid salts, and alkyl trimethyl ammonium chlorides. 
The co-surfactants which can be employed in the practice of the present 
invention include non-nucleophilic alcohols and carboxylates, and 
hydrophilic organic acids such as acetic acid, propionic acid, and butyric 
acid. The preferred co-surfactants are t-butanol, 1,1-dimethyl-1-propanol 
and 1,1dimethyl-1-butanol, the most preferred being the chlorohydrins 
themselves which are formed during the reaction. 
The oxidants which can be employed in the practice of the present invention 
for preparing the chlorohydrin include chlorine, hypochlorous acid (HOCL) 
and tert-butylhypochlorite (t-BuOCL). 
The conditions at which the hypochlorination reaction is most 
advantageously conducted are dependent on a variety of factors, including 
the specific reactants and catalyst employed, if any. In general, the 
reaction is conducted at room temperature up to 100.degree. C. Either plug 
flow reactor conditions or continuous stirred tank reactor (CSTR) 
conditions can be employed. With the latter reactor design, one can 
optionally add both caustic and chlorine to the reaction vessel in order 
to maintain a given pH, usually between pH=1 and pH=7, a process which is 
sometimes referred to as a half bleach process. 
The time and temperature most advantageously employed will vary depending 
on the specific reactants employed, particularly their reactivity. In 
general, the reaction temperature to form the chlorohydrins is from 
0.degree. C. to 120.degree. C. and, most preferably, from 20.degree. C. to 
80.degree. C., and for a time sufficient for the reaction to occur, which 
may be as short as 10 seconds in a continuous or plug flow reactor. 
Preferably, such time period is from 1 minute to 2 hours, more preferably 
from 5 minutes to 1/2 hour and, most preferably, from 10 minutes to 1/4 
hour. The time indicated is residence time in a continuous reactor regime. 
The concentrations at which the reactants are most advantageously employed 
are dependent on a variety of factors including the specific alpha-olefins 
employed and the chlorohydrins being prepared. 
In general, the water to alpha-olefins volume ratio is at least 5 to 1 and 
preferably at least 20 to 1. In most cases, the water to alpha-olefins 
volume ratio does not exceed 100 to 1. 
In general, the oxidants can be employed in an amount of from about 0.8 to 
about 1.2 equivalents based on olefin, preferably, from about 0.9 to about 
1.1, more preferably from about 0.95 to about 1.05 and, most preferably 
1.0 equivalent, based on olefin. Normally the oxidant:olefin ratio is 1:1 
at standard reaction conditions for hypochlorination processes. 
The amount of surfactants which can be employed is, in general, from about 
0.01 to about 5 weight percent, preferably, from about 0.1 to about 2 
weight percent, more preferably from about 0.2 to about 1.5 weight percent 
and, most preferably from about 0.3 to 1.0 weight percent, based on the 
weight of the olefin.

The following working examples are given to illustrate the invention and 
should not be construed as limiting its scope. Unless otherwise indicated, 
all parts and percentages are by weight. 
EXAMPLE 1 
Hypochlorination of 1-octene with t-BuOCL in Water 
Into a 500 mL jacketed resin kettle was added 200 mL of water, 0.625 g of 
C.sub.20-24 alpha-olefin sulfonate (sodium salt, 40% in water) and 0.4 g 
of sodium sulfate. The reaction vessel was fitted with constant speed, 
variable torque mechanical stirrer, pH meter, thermometer, dry ice 
condenser vented to a bubbler, and septum. The mixture was stirred at 500 
rpm and heated to 40.degree. C. and t-BuOCL (98%, 5.32 g, 0.0491 mole) and 
1-octene (5 g, 7.37 mL, 0.045 mole) were added at equimolar rates using 
syringe pumps over a 1 hour period. After the addition was complete, NaOH 
was added (0.05 mole) until the pH reached 9.4 to convert the 
chlorohydrins formed to the corresponding epoxides. The solution was 
analyzed by GC which showed 92% 1,2-epoxyoctane, 1.4% 1,2-dichlorooctane 
and 6.5% bisether by-products. 
EXAMPLE 2 
Hypochlorination of 1-hexene with t-BuOCL in Water 
Into a 500 mL jacketed resin kettle was added 200 mL of water, 0.625 g of 
C.sub.20-24 alpha-olefin sulfonate (sodium salt, 40% in water) and 0.4 g 
of sodium sulfate. The reaction vessel was fitted with constant speed, 
variable torque mechanical stirrer, pH meter, thermometer, dry ice 
condenser vented to a bubbler, and septum. NaOH was added until the pH 
reached 10. The mixture was stirred at 500 rpm and heated to 40.degree. C. 
and t-BuOCL (98%, 7.74 g, 0.0713 mole) and 1-hexene (5 g, 7.4 mL, 0.0594 
mole) were added at equimolar rates using syringe pumps over a 1 hour 
period. After the addition was complete, NaOH was added (0.05 mole) until 
the pH reached 10 to convert the chlorohydrins formed to the corresponding 
epoxides. The solution was analyzed by GC which showed 95% 
1,2-epoxyhexane, 2.7% 1,2-dichlorohexane and 3.2% bisether by-products. 
EXAMPLE 3 
Into a 500 mL jacketed resin kettle equipped with a mechanical stirrer, pH 
probe, chlorine gas bubbler, and addition pumps for adding olefin and 
aqueous sodium hydroxide was placed 400 mL of water and 0.09 g of Sodium 
C.sub.14-16 alpha-olefin sulfonate. The mechanical stirrer was set at 2000 
rpm. To this was added over 5 minutes, 8 g of hexene (0.095 moles), 6.75 g 
of Chlorine gas and sufficient aqueous NaOH to maintain the pH at 6.5 to 
7.0. After this time 20 mL of 5N NaOH was added to the reactor to convert 
the chlorohydrins formed to the corresponding epoxides. The reactor 
contents were analyzed via Gas Chromatography and gave the following 
results: 
75.2% Epoxy Hexane 
13.1% Dichlorohexane 
11.7% Bis-(chlorohexyl ether) 
EXAMPLE 4 
The procedure of Example 3 was repeated except 0.045 g of sodium 
C.sub.14-16 alpha-olefin sulfonate was added instead of 0.09 g. The 
reactor contents were analyzed via Gas Chromatography and gave the 
following results: 
70.2% Epoxy Hexane 
17.0% Dichlorohexane 
12.8% Bis-(chlorohexyl ether) 
EXAMPLE 5 
The procedure of Example 3 was repeated except 0.0225 g of sodium 
C.sub.14-16 alpha-olefin sulfonate was added instead of 0.09 g. The 
reactor contents were analyzed via Gas Chromatography and gave the 
following results: 
48.6% Epoxy Hexane 
30.6% Dichlorohexane 
20.8% Bis-(chlorohexyl ether) 
EXAMPLE 6 
The procedure of Example 3 was repeated except 0.225 g of sodium dodecyl 
sulfate instead of sodium C.sub.14-16 alpha-olefin sulfonate was added. 
The reactor contents were analyzed via Gas Chromatography and gave the 
following results: 
84.5% Epoxy Hexane 
6.2% Dichlorohexane 
9.3% Bis-(chlorohexyl ether) 
EXAMPLE 7 
The procedure of Example 3 was repeated except 0.1125 g of sodium dodecyl 
sulfate instead of sodium C(.sub.14-16) alpha-olefin sulfonate was added. 
The reactor contents were analyzed via gas chromatography and gave the 
following results: 
77.4% Epoxy Hexane 
11.1% Dichlorohexane 
11.5% Bis-(chlorohexyl ether) 
EXAMPLE 8 
The procedure of Example 3 was repeated except 0.056 g of sodium dodecyl 
sulfate instead of sodium C.sub.14-16 alpha-olefin sulfonate was added. 
The reactor contents were analyzed via gas chromatography and gave the 
following results: 
60.9% Epoxy Hexane 
22.1% Dichlorohexane 
17.0% Bis-(chlorohexyl ether) 
EXAMPLE 9 
The procedure of Example 3 was repeated except 0.90 g of Steol CS-130 
(0.220 g active sulfates of ethoxylated alcohols) instead of sodium 
C-.sub.14-16 alpha-olefin sulfonate was added. The reactor contents were 
analyzed via gas chromatography and gave the following results: 
78.0% Epoxy Hexane 
10.8% Dichlorohexane 
11.2% Bis-(chlorohexyl ether) 
EXAMPLE 10 
The procedure of Example 3 was repeated except 0.45 g of Steol CS-130 
(0.110 g active sulfates of ethoxylated alcohols) instead of sodium 
C.sub.14-16 alpha-olefin sulfonate was added. The reactor contents were 
analyzed via gas chromatography and gave the following results: 
79.9% Epoxy Hexane 
11.5% Dichlorohexane 
8.6% Bis-(chlorohexyl ether) 
EXAMPLE 11 
The procedure of Example 3 was repeated except 0.225 g of Steol CS-130 
(0.055 g active sulfates of ethoxylated alcohols) instead of sodium 
C.sub.14-16 alpha-olefin sulfonate was added. The reactor contents were 
analyzed via Gas Chromatography and gave the following results: 
67.8% Epoxy Hexane 
16.9% Dichlorohexane 
15.3% Bis-(chlorohexyl ether) 
COMATIVE EXAMPLE A 
The procedure of Example 3 was repeated except 0.225 g of sodium octyl 
sulfonate instead of sodium C.sub.14-16 alpha-olefin sulfonate was added. 
The reactor contents were analyzed via gas chromatography and gave the 
following results: 
38.9% Epoxy Hexane 
41.9 % Dichlorohexane 
19.2 % Bis-(chlorohexyl ether) 
No microemulsification of product was observed. Instead, macroemulsions 
formed. 
EXAMPLE 12 
The procedure of Example 3 was repeated except 0.225 g of sodium decyl 
sulfonate instead of sodium C.sub.14-16 alpha-olefin sulfonate was added. 
The reactor contents were analyzed via gas chromatography and gave the 
following results: 
68.7 % Epoxy Hexane 
19.8 % Dichlorohexane 
11.5 % Bis-(chlorohexyl ether) 
EXAMPLE 13 
The procedure of Example 3 was repeated except 0.225 g of sodium dodecyl 
sulfonate instead of sodium C.sub.14-16 alpha-olefin sulfonate was added. 
The reactor contents were analyzed via gas chromatography and gave the 
following results. 
81.1 % Epoxy Hexane 
8.2 % Dichlorohexane 
10.7 % Bis-(chlorohexyl ether) 
COMATIVE EXAMPLE B 
The procedure of Example 3 was repeated except 0.225 g of sodium hexadecyl 
sulfonate instead of sodium C.sub.14-16 alpha-olefin sulfonate was added. 
The reactor contents were analyzed via gas chromatography and gave the 
following results: 
45.8% Epoxy Hexane 
31.8% Dichlorohexane 
22.4% Bis-(chlorohexyl ether) 
No microemulsification of product was observed. Instead, macroemulsions 
formed. 
COMATIVE EXAMPLE C 
The procedure of Example 3 was repeated except no surfactant was added. The 
reactor contents were analyzed via gas chromatography and gave the 
following results. 
30.1% Epoxy Hexane 
52.3% Dichlorohexane 
17.6% Bis-(chlorohexyl ether) 
EXAMPLE 14 
Into a 500 mL jacketed resin kettle equipped with a mechanical stirrer, pH 
probe, chlorine gas bubbler, and an addition pump for adding olefin was 
placed 400 mL of water and 0.20 g of sodium C.sub.14-16 alpha-olefin 
sulfonate. The mechanical stirrer was set at 2000 rpm. To this was added 
over 40 minutes, 20 g of allyl chloride (0.264 moles) and 18.56 g of 
Chlorine gas. The reactor contents were analyzed via gas chromatography 
and gave the following results. 
95.56% Allyl chloride Chlorohydrin 
3.76% Trichloropropane 
0.68% dichloropropyl ethers 
EXAMPLE 15 
Into a 500 mL jacketed resin kettle equipped with a mechanical stirrer, pH 
probe, chlorine gas bubbler, and an addition pump for adding olefin was 
placed 400 mL of water and 0.20 g of sodium C.sub.14-16 alpha-olefin 
sulfonate. The mechanical stirrer was set at 750 rpm. To this was added 
over 40 minutes, 20 g of allyl chloride (0.264 moles) and 18.56 g of 
chlorine gas. The reactor contents were analyzed via gas chromatography 
and gave the following results: 
93.52% Allyl chloride Chlorohydrin 
5.36% Trichloropropane 
1.16% dichloropropyl ethers 
EXAMPLE 16 
Into a 500 mL jacketed resin kettle equipped with a mechanical stirrer, pH 
probe, chlorine gas bubbler, and an addition pump for adding olefin was 
placed 400 mL of water and 0.10 g of sodium C.sub.14-16 alpha-olefin 
sulfonate. The mechanical stirrer was set at 750 rpm. To this was added 
over 40 minutes, 20 g of allyl chloride (0.264 moles) and 18.56 g of 
chlorine gas. The reactor contents were analyzed via gas chromatography 
and gave the following results. 
93.65% Allyl chloride Chlorohydrin 
5.23% Trichloropropane 
1.12% dichloropropyl ethers 
EXAMPLE 17 
Into a 500 mL jacketed resin kettle equipped with a mechanical stirrer, pH 
probe, chlorine gas bubbler, and an addition pump for adding olefin was 
placed 400 mL of water and 0.02 g of sodium C.sub.14-16 alpha-olefin 
sulfonate. The mechanical stirrer was set at 750 rpm. To this was added 
over 40 minutes, 20 g of allyl chloride (0.264 moles) and 18.56 g of 
Chlorine gas. The reactor contents were analyzed via gas chromatography 
and gave the following results: 
85.82% Allyl chloride Chlorohydrin 
10.27% Trichloropropane 
3.91% dichloropropyl ethers 
COMATIVE EXAMPLE D 
Into a 500 mL jacketed resin kettle equipped with a mechanical stirrer, pH 
probe, chlorine gas bubbler, and an addition pump for adding olefin was 
placed 400 mL of water. The mechanical stirrer was set at 750 rpm. To this 
was added over 40 minutes, 20 g of allyl chloride (0.264 moles) and 18.56 
g of chlorine gas. The reactor contents were analyzed via gas 
chromatography and gave the following results. 
61.22% Allyl chloride Chlorohydrin 
33.85% Trichloropropane 
4.93% dichloropropyl ethers 
COMATIVE EXAMPLE E 
Into a 500 mL jacketed resin kettle equipped with a mechanical stirrer, pH 
probe, chlorine gas bubbler, and an addition pump for adding olefin was 
placed 400 mL of water. The mechanical stirrer was set at 2000 rpm. To 
this was added over 40 minutes, 20 g of allyl chloride (0.264 moles) and 
18.56 g of Chlorine gas. The reactor contents were analyzed via Gas 
Chromatography and gave the following results. 
74.13% Allyl chloride Chlorohydrin 
17.80% Trichloropropane 
8.07% dichloropropyl ethers 
In the above examples, Examples 3-5, 6-8 and 9-11 demonstrate the 
dependence of chlorohydrin yield on the amount of surfactant for the 
preparation of epoxy hexene using three surfactants which exhibited three 
phase microemulsion behavior. Examples 12 and 13 and Comparative Examples 
A and B show the effect of alkyl tail length on chlorohydrin yield. The 
surfactants used in Comparative Examples A and B gave emulsions and 
resulted in only slight improvements in chlorohydrin yield while the 
surfactants used in Examples 12 and 13 gave microemulsions and resulted in 
substantially better overall chlorohydrin yields. In Comparative Example 
C, no surfactant was used, and a poor yield was obtained. Examples 14-17 
and Comparative Examples D and E describe the hypochlorination of allyl 
chloride with chlorine. Examples 14-17 show the effect of added surfactant 
as well as agitation rate on chorohydrin yield. Comparative Examples D and 
E show the yields obtained when no surfactant is added at the two 
agitation rates used.