US3746588A - Sterilization of nitroparaffin-amine explosives - Google Patents

Abstract

A PROCESS FOR STERILIZING AN AMINE SENSITIZED LIQUID EXPLOSIVE OF THE NITROPARAFFIN TYPE WHICH PROCESS COMPRISES ADDING TO THE SENSITIZED EXPLOSIVE A STERLIZING AGENT, FOR EXAMPLE, POLYCARBONATE, DIPHENYL ESTER OF CARBONIC ACID, FURALDEHYDE, 2,5-DIMETHYL 2,4-HEXADIENE, TRIBUTOXYBORINE, TRIBUTYLESTER OF PHOSPHORIC ACID, TETRAETHYLBOROSILICATE, BENZALDEHYDE, 1-PHENYL-1-PROPANONE, HEXANONE, SUCCINIC ANHYDRIDE, MALEIC ANHYDRIDE OR A COMBINATION THEREOF IN AN AMOUNT EFFECTIVE TO RENDER THE EXPLOSIVE NONDETONABLE.

Description

United States Patent 3,746,588 ST'ERILIZATION 0F NITROPARAFFIN-AMINE EXPLOSIVES Nickolas Brunetz, La Mirada, and Robert A. Haskell,

Long Beach, Calili, assignors to Aerojet-General Corporation, El Monte, Calif. No Drawing. Filed Mar. 29, 1971, Ser. No. 129,245 Int. Cl. C06b 7/00 U.S. Cl. 14989 2 Claims ABSTRACT OF THE DISCLOSURE A process for sterilizing an amine sensitized liquid explosive of the nitroparaffin type which process comp-rises adding to the sensitized explosive a sterilizing agent, for example, polycarbonate, diphenyl ester of carbonic acid, furaldehyde, 2,5-dimethyl 2,4-hexadiene, tributoxyborine, tributylester of phosphoric acid, tetraethylborosilicate, benzaldehyde, 1-phenyl-1-propanone, hexanone, succinic anhydride, maleic anhydride or a combination thereof in an amount effective to render the explosive nondetonable.

This invention relates to a method for rendering nondetonable sensitized liquid explosive of the nitroparaflinamine type. In particular, this invention relates to sterilizing an explosive composition containing nitroparafiins sensitized with primary or secondary organic amines, or hydrazines.

Nitroparaflin explosive compositions find valuable application in quarrying where a powerful explosive having a high rate of detonation is required. The superior properties of the amine sensitized nitroparaflin explosives make them useful in mining, for military purposes, in oil well production and other applications where the use of explosives is necessary. Liquid nitroparafiin explosives of the foregoing type are described in U.S. Pats. 3,239,395 Lawrence, 3,132,060 Beegle et al., 2,967,099 Pool, and 2,690,964 Maisner. It will be appreciated that once a nitroparaflin explosive has been sensitized with the amine, it must be exploded or otherwise it provides a dangerous disposal problem.

It has now been discovered that the addition of certain sterilizing agents to the sensitized nitroparaflin liquid explosive renders the explosive inert and nondetonable. It has been established by test that the following materials or combinations thereof are efiective as sterilizing agents for amine-sensitive nitroparaflin explosives: polycarbonate, diphenyl ester of carbonic acid, furaldehyde, 2,5- dimethyl 2,4 hexadiene, tributoxyborine, tributylester of phosphoric acid, tetraethylborosilicate, benzaldehyde, 1- phenyl-l-propanone, hexanone, succinc anhydride (2,5- diketotetrahydrofuran), and maleic anhydride 2,5-furanedione).

It is believed that the addition of the sterilizing agent reduces the nitroparafiin, destroys the amine salt earlier formed in the sensitizing reaction, produces water and other compounds including a semipolymer. The exact sterilizing reaction is not fully known. However, it is known that the sterilizing agent, polycarbonate for example, dissolves completely only in the sensitizer or the sensitized nitroparafiin liquid. It has been demonstrated that an amine saturated with the sterilizing agent is still capable of sensitizing a nitroparaffin fuel when added thereto; and, it is only after a period of time has lapsed that the thus sensitized nitroparatfin explosive becomes inert and nondetonable. The time required to elfect sterilization, as described in the preceding situation, is of approximately the same length of time as that required in the more usual later addition of the sterilizing agent to the previously sensitized amine-hydrocarbon mixture. The sensitized explosive becomes inert in the last one percent of the sterilization time before completion of the sterilization reaction. Until then, the explosive shows no substantial decreased output in energy and the explosive may be detonated even though the sterilization has been added sometime earlier.

Typically, the sterilizing agent is employed in an amount in the range of 4 to 15 percent by weight of the sensitized explosive. The speed with which the several sterilizers work varies considerably with diphenylcarbonate being the fastest sterilizer. Polycarbonate is also a particularly desirable material. The time parameter for sterilization may be altered somewhat by the concentration of the sterilizer employed, with an increase in concentration decreasing the time required to effect desensitization or sterilization, which typically occurs within five minutes after the addition of the sterilizer. The sterilizer polycarbonate, however, requires several (2-36) hours for its reaction depending on the concentration of the polycarbonate, rod or resin and on the temperature and concentration of the explosive. It is constant within the same system. Once sterilization is achieved, the reaction is irreversible and the explosive remains inert and cannot be detonated by any means of normal initiation. The timing of the sterilizing process may be controlled by a timing capsule which has a controlled solution rate seal. For example, polycarbonate seal will give a l0-24 hours delay of capsule opening, depending on the thickness of the seal.

Nitroparaflins utilizable in the process of present invention include any of the liquid nitroparafiins, such as, nitromethane, dinitromethane, nitroethane, dinitroethane, nitro propane, nitrobutane, nitropentane, and nitrohexane including their many isomeric structures. The preferred nitroparafiin is mononitromethane, optionally containing up to 30 percent by weight of nitroethane or nitropropane based on the weight of the nitromethane,

The sensitizer is typically a primary or secondary amine, e.g., propylene diamine, ethylene diamine, diethylene triarnine, triethylene tetramine, tetraethylene pentamine, triethylamine, tripropylamine, any of the butyl amines (n, iso, sec or ter), hexylamine, dimethylcyclohexylamine, dimethyl pentylamine, hydrazine, piperazine, methyl piperazine and furfurylamine.

The sensitizer may be hydrous or anhydrous, its character does not influence the sterilization time or effect.

The procedure used for testing the effectiveness of the various sterilizers comprised loading two different sizes of test tubes (10 mm. ID. and 25 mm. I.D.), and somewhat larger containers with an amine-sensitized nitromethane liquid explosive. Twenty each of the three size vessels (the two test tubes and container) were utilized. Five of each size were test fired over steel or aluminum witness plates. Typical dents were 0120-0200 inch deep, indicating high order of initiation and propagation. The sterilizing agent being tested was added to the each of the remaining test tubes and containers of the explosives. After five minutes, ten of the so-sterilized explosives of each size of the three vessels were test fired over witness plates using Du Pont No. 8 or E-83 detonators for initiation.

In each instance, the lack of dent on the witness plate indicated no firing and no detonation of the explosive, thus demonstrating the effectiveness of the sterilizing agent. An attempt was made to re-sensitize the remaining test tubes or containers of the sterilized explosives by adding thereto more of the amine sensitizer. The thusattempted re-sensitized explosives were test fired using No. 8 or E-83 detonators. In all instances, it proved impossible to re-sensitize the explosive once it had been sterilized.

What is claimed is:

1. The improvement in the handling of a nitroparatfin liquid explosive wherein the sensitized explosive is later desensitized, said improvement comprising:

placing the nitroparafiin in a detonable form by adding thereto an amine sensitizer to form a sensitized liquid explosive consisting essentially of the nitroparaffin and the amine;

incorporating in the sensitized explosive a desensitizing agent in an amount effective to render the explosive nondetonable, said desensitizing agent being selected from the group consisting of polycarbonate, diphenyl ester of carbonic acid, furaldehyde, 2,5-dimethyl 2,4- hexadiene, tributoxyborine, tributylester of phosphoric acid, tetraethylborosilicate, benzaldehyde, 1- phenyH-propanone, hexanone, succinic anhydride, maleic anhydride or a combination thereof; and

permitting the desensitizing agent to act to place the nitroparafiin explosive in an inert, nondetonable form.

2. A process in accordance with claim 1 wherein the 10 sterilizing agent comprises 4 to 15 weight percent of the liquid explosive.

References Cited UNITED STATES PATENTS 5/1962 Fox l4989 X 4/1964 Bost et al 14989 X