Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfate esters
Reexamination Certificate
2002-02-14
2004-06-08
Griffin, Walter D. (Department: 1764)
Organic compounds -- part of the class 532-570 series
Organic compounds
Sulfate esters
C585S324000, C510S155000, C510S156000
Reexamination Certificate
active
06747165
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a process for preparing (branched-alkyl)arylsulfonates and to compositions of the (branched-alkyl)arylsulfonates per se. This invention also relates to a process for preparing intermediate branched alkyl aromatic hydrocarbons and to compositions of the branched alkyl aromatic hydrocarbons per se.
BACKGROUND OF THE INVENTION
WO-99/05244, WO-99/05082 and U.S. Pat. No. 6,111,158 relate to alkylarylsulfonate surfactants of which the alkyl groups are branched. Sources of the alkyl groups are for example paraffins with limited branching obtained by delinearization of linear paraffins.
U.S. Pat. No. 5,849,960 relates to surfactant sulfates based on branched alcohols. The branched alcohols in question have an average number of branches per molecule chain of at least 0.5. The branching comprises not only methyl branching but also ethyl branches, whilst the occurrence of longer branching is not excluded. The branched alcohols are made from branched olefins, which are made by skeletally isomerizing linear olefins.
The market always asks for improvements in the performance of existing detergent formulations, inter alia by improving the surfactants present in the detergent formulations. For example, the laundry market asks for improvements in the surfactants' biodegradability, their cold water solubility and their cold water detergency. At least an improvement is sought in the balance of the properties. By the terminology “an improvement in the balance of the properties” it is meant that at least one property is improved, whilst at least one of the other properties is not deteriorated.
The present invention seeks to provide improvements in the performance of the known alkylarylsulfonate surfactants, or at least in an improvement in the balance of their performance properties. Relevant performance properties are biodegradability, cold water solubility and cold water detergency, for example cold water detergency in water of low hardness and in water of high hardness. Other relevant performance properties are the compatibility of the alkylarylsulfonate surfactants with other components present in detergent formulations, as described hereinafter, in particular, the compatibility with enzymes, i.e. the inability of the alkylarylsulfonate surfactants to denature enzymes during storage in an aqueous medium. Again other relevant performance properties, in particular for personal care applications, are mildness to the skin and to the eyes and the ability of high foaming, preferably providing foam with a fine structure of the foam cells. Further, an improved performance is sought as a chemical for enhanced oil recovery applications and for the removal of oil spillage, viz. an improved ability to emulsify oil/water and oil/brine systems and to stabilize emulsions of oil and water or brine, in particular at high temperature. Independently, the present invention seeks to provide a method for the manufacture of alkylarylsulfonate surfactants which is more versatile and economically more attractive than the known methods.
SUMMARY OF THE INVENTION
In accordance with this invention alkylarylsulfonate surfactants are prepared by dehydrogenating selected branched paraffins to produce branched olefins. These branched olefins can be converted into branched alkyl aromatics and subsequently into alkylarylsulfonate surfactants. It is an advantage of this invention that surfactants and intermediates can be made with a very low content of molecules which have a linear carbon chain. It is another advantage of the invention that products can be made of which the molecules have a low content of branches having three or more carbon atoms. It is also an advantage of the invention that products can be made of which the molecules have a low content of quaternary aliphatic carbon atoms. Without wishing to be bound by theory, it is believed that the presence of quaternary aliphatic carbon atoms in the molecules of the (branched-alkyl)arylsulfonate surfactants prevents to some extent their biodegradation and the presence of quaternary aliphatic carbon atoms in the isoparaffinic composition is therefore preferably avoided. In fact, it has been determined that the presence of 0.5% or less quaternary aliphatic carbon atoms in the molecules of the surfactants renders the surfactants substantially more biodegradable.
Accordingly, the present invention provides a process for preparing branched olefins, which process comprises dehydrogenating an isoparaffinic composition over a suitable catalyst which isoparaffinic composition has been obtained by hydrocracking and hydroisomerization of a paraffinic wax and which isoparaffinic composition comprises paraffins having a carbon number in the range of from 7 to 35, of which paraffins at least a portion of the molecules is branched, the average number of branches per paraffin molecule being at least 0.5 and the branching comprising methyl and optionally ethyl branches.
The invention also provides a process for preparing branched alkyl aromatic hydrocarbons, which process comprises contacting branched olefins with an aromatic hydrocarbon under alkylating conditions, which branched olefins have been obtained by a process which comprises dehydrogenating an isoparaffinic composition over a suitable catalyst which isoparaffinic composition comprises paraffins having a carbon number in the range of from 7 to 35, of which paraffins at least a portion of the molecules is branched, the average number of branches per paraffin molecule being at least 0.5 and the branching comprising methyl and optionally ethyl branches.
The invention also provides a process for preparing (branched-alkyl)arylsulfonates, comprising sulfonating branched alkyl aromatic hydrocarbons which branched alkyl aromatic hydrocarbons have been prepared by the process for preparing branched alkyl aromatic hydrocarbons in accordance with this invention.
Further, the invention provides a branched olefin composition, which is obtainable in accordance with this invention.
Further, the invention provides a branched alkyl aromatic hydrocarbon composition which is obtainable in accordance with this invention.
In a further aspect the present invention provides a (branched-alkyl)arylsulfonate composition which is obtainable in accordance with this invention.
Without wishing to be bound by theory, it is believed that any improvement in the performance properties of the (branched-alkyl)arylsulfonates prepared in accordance with this invention, compared with the known (branched-alkyl)arylsulfonates, resides in a difference in the distribution of branching along the respective paraffinic chains. Such differences in the distribution of branching are truly unexpected in view of the prior art and, therefore, they are inventive.
DETAILED DESCRIPTION OF THE INVENTION
As described herein, the isoparaffinic composition and the compositions of branched olefins, branched alkyl aromatic compounds and (branched-alkyl)arylsulfonates derived therefrom are generally mixtures comprising molecules with different, consecutive carbon numbers. Typically at least 75% w, more typically at least 90% w, of these compositions represent a range of molecules of which the heaviest molecules comprises at most 6 carbon atoms more than the lightest molecules.
The isoparaffinic composition comprises paraffins having a carbon number in the range of from 7 to 35, of which paraffins at least a portion of the molecules is branched. Preferably, the isoparaffinic composition comprises paraffins having a carbon number in the range of from 7 to 18, more preferably from 10 to 18. Preferably at least 75% w, more preferably at least 90% w, of the isoparaffinic composition consists of paraffins having a carbon number in the range of from 10 to 18. In practice, frequently at most 99.99% w, more frequently at most 99.9% w, of the isoparaffinic composition consists of paraffins having a carbon number in the range of from 10 to 18. It is most preferred that the isoparaffinic composition comprises paraffins having a carbon number in th
Ayoub Paul Marie
Fenouil Laurent Alain Michel
Murray Brendan Dermot
Arnold Jr. James
Griffin Walter D.
Shell Oil Company
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