FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL
Specification
(See section 10 and rule 13)
IMPROVED PROCESS FOR HEAT STABLE CHLORONATED PARAFFIN WAX
ADITYA BIRLA SCIENCE & TECHNOLOGY COMPANY LTD.
an Indian Company
of Aditya Birla Center, S. K. Ahire Marg, Worli, Mumbai 400 025,
Maharashtra, India
THE FOLLOWING SPEC IFICATION DESCRIBES THE INVENTION.

TITLE:
Improved Process for Heat Stable Chlorinated Paraffin wax.
FIELD OF INVENTION
The present invention relates to the field of hydrocarbons in particular paraffins. In chemistry, paraffin is the common name for the alkane hydrocarbons with the general formula CnH2n+2. More particularly present invention relates to paraffin wax. Paraffin wax refers to the solids with n=20-40.The present invention relates to improved process for heat stable chlorinated paraffin wax.
BACKGROUND
In Prior Art, the preparation of chlorinated hydrocarbon containing from 8-24 carbon atoms and having a chlorine content of more than 60% is carried out using Mercury Cell chlorine. Chlorine obtained from Mercury Cell technology posses purity in range of 97-99% which, does not affect the reactivity for paraffin chlorination and heat stability of the chlorinated paraffin product. However, with increasing environmental hazards, the use of Mercury Cell chlorine technology is not preferred today. Mercury Cell technology is getting replaced by environmental friendly Membrane Cell technology.
Compared to the Mercury Cell chlorine, the chlorine produced with Membrane Cell technology, purity nearly >99% shows reduced reactivity for paraffin chlorination, which leads to the formation of carboneous or pitchy product, which in addition to decreasing the yield and poor heat stability of the chlorinated paraffin product.


The reaction yields hydrogen chloride as a byproduct, which is scrubbed from the off-gases, with water. In absence of full conversion of chlorine, mrreacted chlorine in the off-gases adds on the cost of recycling the chlorine. Chlorine produced from membrane technology produces more amount of un-reacted chlorine which leads to higher production of hypo.
Thermal control is essential with highly exothermic reactions, and this necessitates dispersion of the reaction heat in order to avoid any dangerous rise in temperature, de-chlorination reactions of less thermally stable product which also account for rise in temperature, which would also lead to the formation of carboneous or pitchy product, deposit on the inner surfaces of the reactor and adversely affect heat exchange or even obstruct the reactor and adversely affect the progress of reaction and color and thermal stability of product.
Again in the prior art little attempt has been made to solve both chlorination and color stability of chlorinated paraffin synthesis from molecular membrane chlorine. Various proposals have heretofore been made for stabilizing highly-chlorinated paraffin waxes, and these suggestions having included the addition of various materials designed to prevent the evolution of hydrogen chloride, whatever the cause may be, from the materials when they are exposed to heat. These prior suggestions, however, have not been entirely satisfactory because the temperature of stability of the chlorinated paraffin wax has not true of stability of the chlorinated paraffin wax has not been raised significantly, or for other reasons.
The prior art stabilizers have not proved satisfactorily for various reasons! for example epichloro hydrin, one of the best of prior art stabilizer has boiling point(ll7°C) which is not suitable for highly chlorinated paraffin wax. The glycols (US2722557) are unsatisfactory because their addition in small amount


decreases overall chlorine content of stabilized wax. Alkaline liquids (US2119149), on other hand, require greater ease of separation after treatment. Solution provided in patent (US3194846) for stability of chlorinated paraffin is applicable for short duration,' stability achievable for maximum time is 9.5minutes at 175°C. Another patent (US3284519) was taken to impart significantly improved heat stability to the waxes. In accordance with aforesaid invention, stabilizer used in process was diazo dicarboxylate, due to safety regulation DEDAD is not recommended in process. In patent US3848005 author explain about the use of EDTA in process for inhibiting the iron-catalyzed dehydrochlorination which occurs in chlorine fractions contaminated with small quantities of ferric ion-containing materials, but this process failed to achieve the product heat stability.
OBJECTS OF THE INVENTION
An object of the invention is to provide a method which meets the following requirement.
1) Improvement in chlorine reactivity.
2) Practically full conversion of the gaseous reagents and thus reduces the amount of un-reacted C12.
3) Control of reaction from thermal standpoint.
4) Elimination of flashing during reaction.
5) Improved heat stability of the product.
SUMMARY OF INVENTION
Thus according to the present invention an improved method of chlorinating a straight-chain paraffin having 8 to 24 carbon atoms in the molecule, in the liquid phase in a reactor is provided, the method comprising reacting gaseous chlorine and a liquid paraffin feed in a vertically extending tubular reactor


through a bottom inlet. The invention envisages an improvement of enhancing the rate of chlorination and of the final product at a temperature 180°C.
Advantages of this invented method include:
1. The ability to carry out the reaction at controlled temperature at enhanced reaction rate in presence of promoter.
2. Promoter is used in very small quantities (~ 12-800 ppm), does not affect downstream applications of CP.
3. Promoter achieves greater heat stability.
4. The ability to improves the Cl2 reactivity and thus reduces the amount of un-reacted Cl2 .
5. Batch-cycle time can be reduced by 3-4 hrs, without compromising yield & quality.
6. Flashing of the paraffin is eliminated.
7. Insignificant cost of the promoter.
8. Low operational / overhead cost.
9. Improved atom economy of chlorine / less un-reacted chlorine.
10. No wasteful by-products / Waste minimization at source.
11. Robust - Versatile solution, one solution for both heat stability and reactivity. No CAPEX required.
12. Making technology switchover from mercury to membrane cell a success.
Reaction proceeds faster in the presence of the promoter in accordance with this invention; over all batch cycle time was reduced by3-4 hours. Promoter quantity used was in between 12-800 ppm. Stability achieved was significant. Flashing of paraffin was eliminated.


DETAILED DESCRIPTION OF INVENTED PROCESS
This invention envisages an improved process for producing stabilized chlorinated paraffins, waxes and to method of effecting such stabilization.
Chlorinated paraffins, waxes, as prepared by various known methods, slowly decompose, liberating hydrogen chloride. This characteristic renders them unfit for many uses for which they would otherwise be well suited.
A number of substitutive chlorination methods are known in the art for organic compounds employing gaseous chlorine, wherein the thermal or catalytic reaction is carried out in a liquid or gaseous phase.
This invention envisages a liquid phase, catalytic method of chlorinating paraffins by means of gaseous chlorine. More particularly, a method is described which can be employed for preparing chloro derivatives of liner chain paraffins having a carbon atom number in molecule of from 8-22/24. Paraffin mixture thermally chlorinating in the vapor-liquid phase the preferred operational temperature from room temperature up to about 200°C, the preferred temperature up to about 150 C, the most preferred temperature ranging between 60 C and 120 C.
By use of this method it is possible to obtain high chloroparaffin yields and to practically exhaust the chlorine fed in the reaction, there by avoiding the formation of carbonaceous, pitchy, poor thermally stable products.
The chlorination reaction may be carried out in the range of atmospheric pressure to about 3 atmospheres over pressure. However ambient pressure or only slightly raised pressure is preferred.
The process employed for the synthesis of chlorinated derivatives of paraffin in accordance with this invention with a carbon atom number in the molecule


ranging between 8-24. The reaction temperature ranges between 80 and 150C, preferably 90-130 C.
The reactor which may be used may be of glass, lead or carbon steel, are of cylindrical shape, and preferably equipped with external jacket for circulation of a coolant, pre-heater for foot liquid feed, over head gas-liquid separating arrangement and gas distribution arrangement.
The promoter used in reaction is to speed up the chlorination reaction, suppress the dechlorination reaction and to bring the thermal stability to final product which includes. Any substance that gives the following action/s during the paraffin chlorination and thermal exposure (to CP) can act as a promoter for the paraffin chlorination,
Initiates the free radical reactions! generate and propagate the free radicals required for the paraffin chlorination! eliminate and/or replace labile chloride on the chlorinated paraffin molecule and interrupt color development by addition across the double bond. The promoters can be any of the following compounds in isolation or in combination. Mercaptides, carboxylates, sulfides, maleates of Calcium, Barium, Lead & organo tin compounds e.g. mono di alkyl tin.
Examples :
la) In a lead-lined reactor, 2.4 TON good quality normal paraffin (Reliance NP, Source: Reliance Industries Ltd.), preheated to 50 C was taken for chlorination. The reactor was equipped with the cooling jacket, chlorine inlet sparger, off-gas outlet valve and temperature sensors. Arrangements for direct supply of chlorine gas at 30 C from the BCCL Chlor-Alkali plant were done. The reaction temperature was controlled with the combination of chlorine flow and cooling water-inlet flow. Off-gases of the reaction were passed through the water scrubber for removal of HCl-gas. The scrubber outlet was given to the caustic solution tank for converting the un-reacted chlorine into sodium hypochlorite.


Chlorination reaction was run for 1400 minutes and the temperature was allowed to rise from 50 to 94 C during the reaction. At the end of 1400 minutes the chlorine flow was stopped and air flow to remove the HC1 / dissolved Cb was started. The air was passed for 2 hours, meamyhile the reactor temperature dropped to 50 C. At this temperature the product was unloaded in the aeration tank, final aeration was done for 2 hr. 45 KG of epoxy soya stabilizer was added to the product for better shelf life.
lb) The same procedure as given in la was followed with addition of 12 g of methyl mercaptide (promoter) to the reactor in the beginning and addition of 7kg of promoter AB-1STC to the final product.
The invention will be described with reference to the accompanied drawings.
The temperature and specific gravity profiles of reactions la and lb are given in figure 1.Figure 2 clearly depicts the advantage of the promoter. The reaction was carried out at little higher temperatures without the danger of flashing and the specific gravity increase was faster in the reaction with the promoter. This could reduce the total run time by at least 15 %, more fast reaction can be carried out by further optimization. The actual color difference after the heat stability tests for A (without epoxy/additive), B(epoxy+promoter) are given in Figure 2. Heat stability results are given in table 1.

Experiments
Property la lb
Density gm/ml 1.3 1.3


Heat stability
% wt. loss after 1 hrs @ 180°C 0.33% 0.17%
Heat Test at 200°C fail pass
Promoter absent present

Table 1

The reactions (2a & 2b) were carried out in similar manner as mention above in lb except that the feed used was raw paraffin (lower in quality & cheaper) preheated to 37-38 C. The temperature and specific gravity profiles of reactions 2a and 2b are given in Figure 3.The actual color difference after the heat stability tests for D(without additive) and E(with promoter) are given in Figure 4. Heat stability results are given in table 2.

Experiments
Property 2a 2b
Density gm/ml 1.3 1.3
Heat Stability
%HC1 after 1 hrs @ 180°C 0.68% 0.45%
Heat Test at 200°C fail pass
catalyst absent present

While considerable emphasis has been placed herein on the specific steps of the preferred process, it will be appreciated that many steps can be made and that many changes can be made in the preferred steps without departing from the principles of the invention. These and other changes in the preferred steps of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.