Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
1991-11-15
2001-01-23
Trinh, Ba K. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C549S555000, C549S558000, C549S563000, C564S295000
Reexamination Certificate
active
06177577
ABSTRACT:
TECHNICAL FIELD
This invention relates to novel dicationic and polycationic monoprimary alcohols and functional derivatives thereof. The novel compounds are characterized by having a single primary hydroxyl function, which permits the dicationic or polycationic alcohols to be used in making derivatives which are not crosslinked, as is a problem presented by dicationic or polycationic diols or polyols, known in the art.
BACKGROUND ART
Representative references disclosing dicationic or polycationic compounds, containing hydroxyl functionality, include Lewis et al. (U.S. Pat. No. 3,567,729), Matter et al. (U.S. Pat. No. 3,632,559), Evani et al. (U.S. Pat. No. 4,156,775), Hoppe et al. (U.S. Pat. No. 4,093,605) and Bachem et al. (U.S. Pat. No. 4,737,576). The compounds disclosed by these references are generally symmetrical in structure and have a plurality of secondary hydroxyl functions. The compounds are often not highly reactive, or selectively reactive, for example, with starch. Use of these compounds, for example, to prepare cationic starch, give products which are more or less highly cross-linked and which may be unacceptable for many utilities.
It is an object of this invention to provide novel dicationic or more-highly cationic monoprimary alcohols, which can be used to prepare highly cationized derivatives, for example, of starch, without presenting a problem of undesired cross-linking of the thus-treated starch.
DISCLOSURE OF INVENTION
This invention relates to compounds of the general formula
wherein each alk is independently alkyl of 1-8 carbon atoms; each ALK is independently alkyl of 1-8 carbon atoms; each R
1
, R
2
, R
3
, R
4
or R
5
is independently H or alkyl of 1-8 carbon atoms; n is 2-5; G is H, CR
1
R
2
CR
3
OHCR
4
R
5
X or
X is Cl, Br or I; An
−
is a monovalent anion and p is 1-10, provided that the compound is soluble in water.
In another aspect, this invention relates to cationic starch, obtained by reaction between starch and a compound of the foregoing general formula, wherein G is
or CR
1
R
2
CR
3
OHCR
4
R
5
X.
This invention also relates to a process for making a dicationic monoprimary alcohol, comprising reacting a halohydroxyalkyl trialkylammonium halide of the formula
wherein each alk is independently of 1-8 carbon atoms; each R
1
, R
2
, R
3
, R
4
and R
5
is independently H or alkyl of 1-8 carbon atoms; X is Cl, Br or I and X
−
is Cl
−
, Br
−
or I
−
with a dialkylalkanolamine of the formula ALK
2
NC
n
H
2n
OH, wherein each alkaline material to produce a dicationic alcohol.
This invention further relates to a method of treating paper furnish, comprising adding to the paper furnish a thus-prepared cationic starch.
In another aspect, this invention relates to a method for flocculating solids in waste waters, comprising adding to the waters being treated a compound of the general formula, wherein G is H, in an amount sufficient to flocculate the solids.
DETAILED DESCRIPTION OF THE INVENTION
The compounds of this invention can be prepared by the following general procedure, starting from a chloro-2-hydroxypropyl trialkylammonium chloride:
wherein alk is alkyl of 1-8 carbon atoms; ALK is alkyl of 1-8 carbon atoms; and is n is 2-5.
In the first step of the process a 3-chloro-2-hydroxypropyl trialkylammonium chloride, for example, 3-chloro-2-hydroxypropyl trimethylammonium chloride, is converted to an epoxide by dehydrohalogenation with an alkaline material, for example, sodium hydroxide. This starting material corresponds to a compound in which each alk is methyl. 3-Chloro-2-hydroxypropyl trimethylammonium chloride can be prepared and purified as disclosed by Langher et al. (U.S. Pat. No. 3,532,751) and Tasset (U.S. Pat. No. 4,602,110), herein incorporated by reference.
The alkaline material can be selected from alkali metal and alkali earth metal oxides, hydroxides and carbonates. Representative alkaline materials include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium oxide, sodium carbonate, sodium bicarbonate nahcolite, calcium oxide, calcium hydroxide and calcium carbonate, magnesium oxide, magnesium hydroxide, magnesium carbonate, dolime and the like. Mixtures of alkaline materials can be used. Of the foregoing alkaline materials, sodium and potassium hydroxides are preferred.
The reaction is generally carried out in an aqueous medium with cooling, generally to 0° C. to 50° C. The amount of alkaline material used for converting the halohydrin to the epoxide is at least one equivalent of alkaline material per equivalent of halohydrin. Preferably, a slight excess of alkaline material is used, preferably of the order of 1.05-1.15 equivalent of alkaline material per equivalent of halohydrin. The thus-prepared 2,3-epoxypropyl trialkylammonium is used without further purification for the next step of the synthesis.
It will be understood that preparation of the 2,3-epoxypropyl trialkylammonium chloride need not be carried out immediately before use, should this material be available in large quantities from another source.
The intermediate 2,3-epoxypropyl trialkylammonium halide, in this case, 2,3-epoxypropyl trimethylammonium chloride, is reacted with a dialkylaminoalkanolamine, represented in the schematic formulation as ALK
2
C
n
H
2n
OH. In a typical case, the dialkylaminoalkanolamine is N,N-dimethylethanolamine, that is, a compound wherein each alk is methyl and n is 2.
Condensation of the 2,3-epoxypropyl trialkylammonium halide and dialkylalkanolamine is initiated by adding the dialkylalkanolamine to a chilled solution of epoxypropyl trialkylammonium chloride in small amounts, preferably by dropwise addition. After all of the dialkylalkanolamine is added and the exothermic reaction has subsided, the reaction mixture is heated to cause the reaction to go to completion. Heating at 40-70° C. is generally preferred, so as to accomplish completion of the reaction within a reasonable time. The progress of the reaction can be followed by high pressure liquid chromatography (HPLC). The disappearance of starting epoxide or maintenance of a constant level of unreacted dialkylalkanolamine can be used as measures of the extent of reaction. In the case of a reaction using dimethylethanolamine, the reaction is usually complete after 5 hours' heating at about 50° C.
Initial isolation of the product is accomplished by adjusting the pH of the resulting mixture to about 2.0, using, for example, hydrochloric acid. It will be understood that the acid selected determines the anion or anions, which are present in the complex and that any strong mineral or organic acid, for example, sulfuric acid, trifluoroacetic acid, chloroacetic acid, can be used for this purpose.
Following removal of residual dialkylalkanolamine from the reaction mixture, conveniently by freeze drying, crude reaction product, which corresponds to a dicationic monoprimary alcohol of this invention, is usually an oily material. The crude dicationic monoprimary alcohol is frequently yellowish in color.
The thus-prepared dicationic monoprimary alcohol can be purified by being taken up in hot isopropanol and filtered to remove salt by-products of the reaction. Solvent can be evaporated from the filtrate using, for example, a rotary evaporator, to produce a hygroscopic white powdery product. It is preferred to store the dicationic monoprimary alcohol under nitrogen or other dry inert gas, should the product not be used immediately after preparation.
The dicationic monoprimary alcohol, of the general formula
can be converted directly to an epoxide by reaction with epichlorohydrin and an alkaline material. The chlorohydrin can be prepared from the epoxide by addition of hydrochloric acid. The chlorohydrin is generally preferred to the epoxide for storage stability.
It is preferred to carry out the reaction in a solvent, of which the lower alkanols are representative. The lower alkanols include isopropanol, n-butanol, isobutanol, sec-butanol and tert-butanol, as well as the various amyl alcohols. Secondary alcohols, including isopropanol and isobu
Frank R. Keith
Roerden Dorothy L.
The Dow Chemical Company
Trinh Ba K.
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