Patents by Inventor Reddy Damavarapu

Reddy Damavarapu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9850181
    Abstract: A single-step method for preparing nano-sized cocrystals of explosive material by preparing a coformer solution having an explosive precursor dissolved into a liquid medium and a second explosive precursor dispersed in the liquid medium. The viscosity and solubility of the coformer solution may be modified by addition of binders, plasticizers, surfactants and anti-foaming agents to the coformer solution. The coformer solution is then milled to mechanically form the cocrystals. Further milling produces the desired cocrystal sizes.
    Type: Grant
    Filed: June 8, 2017
    Date of Patent: December 26, 2017
    Assignee: The United States of America as Represented by the Secretary of the Army
    Inventors: Rajen Patel, Victor Stepanov, Reddy Damavarapu, Hongwei Qui
  • Patent number: 9790137
    Abstract: A method of manufacturing a CL-20/HMX cocrystalline explosive which is coated in a polymeric binder, so as to be useful as an explosive molding powder. The cocrystalline material having a desirable average crystal size of from about 300 nm to about 1000 nm, which crystals are intimately coated with a polymeric binder and are produced as granular agglomerates that are less than on average 5 microns in size, and which crystals are relatively easy and safe to handle, transport, store and use. The method involving spray drying a CL-20 and HMX solvent solution containing a polymeric binder to form an intermediary amorphous material—which intermediary is then heated to cocrystallize the CL-20/HMX into the desired size cocrystals and aggregates thereof—which are coated in said polymeric binder.
    Type: Grant
    Filed: June 8, 2015
    Date of Patent: October 17, 2017
    Assignee: The United States of America as Represented by the Secretary of the Army
    Inventors: Victor Stepanov, Reddy Damavarapu, Rajen Patel, Hongwei Qiu
  • Patent number: 9701592
    Abstract: A safe and simple method for synthesizing insensitive nano-size cocrystals of high explosive materials such as HMX and Cl-20 by suspending the explosive materials in a nonsolvent solution and bead milling the solution.
    Type: Grant
    Filed: August 6, 2015
    Date of Patent: July 11, 2017
    Assignee: The United States of America as Represented by the Secretary of the Army
    Inventors: Rajen B. Patel, Hongwei Qiu, Victor Stepanov, Reddy Damavarapu
  • Patent number: 8608879
    Abstract: The present invention is a flare illuminant composition, useful in hand-held signals, which composition is environmentally friendly and economical, containing a commercially available, aromatic, high energy, amine-based organic compound, 5-aminotetrazole, in place of the conventional and toxic KClO4, or, for the known alternative to KClO4, expensive, strontium bis-(1-methyl-5-nitriminotetrazolate)monohydrate.
    Type: Grant
    Filed: December 19, 2011
    Date of Patent: December 17, 2013
    Assignee: The United States of America as Represented by the Secretary of the Army
    Inventors: Jesse J. Sabatini, Gary Chen, Amita Nagori, Reddy Damavarapu
  • Patent number: 8492541
    Abstract: Energetic candidate azido heterocycles and their synthesis are described.
    Type: Grant
    Filed: August 3, 2011
    Date of Patent: July 23, 2013
    Assignee: The United States of America as Represented by the Secretary of the Army
    Inventors: Raja Duddu, Paritosh Dave, Reddy Damavarapu, Rao Surapaneni
  • Patent number: 8153786
    Abstract: Energetic candidate azido heterocycles and their synthesis are described.
    Type: Grant
    Filed: July 16, 2008
    Date of Patent: April 10, 2012
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Raja Duddu, Paritosh Dave, Reddy Damavarapu, Rao Surapaneni
  • Patent number: 8133993
    Abstract: A method for synthesizing pentanitrohexaazaisowurtzintane under neutral reaction conditions. Which synthesis involves treating a solution of hexanitrohexaazaisowurtzitane in ethyl acetate in the presence of a catalytic quantity of palladium on a carbon substrate, until a heterogeneous mixture is formed. This heterogeneous mixture is hydrogenated under a balloon atmosphere until the starting hexanitrohexaazaisowurtzitane is substantially reacted. The resulting pentanitrohexaazaisowurzitane mixture is filtered, dried and recovered from the dried residue through a Si-gel column.
    Type: Grant
    Filed: November 26, 2008
    Date of Patent: March 13, 2012
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Raja Duddu, Paritosh Dave, Reddy Damavarapu, Rao Surapaneni
  • Patent number: 8002917
    Abstract: A method of adjusting the yield of a manufactured compound comprising primarily two energetic materials to yield a product comprising primarily one of the two energetic materials. Specifically, embodiments of the present invention provide a method of purifying a compound primarily comprising RDX and HMX to achieve a desired purity of RDX with an acceptable yield percentage. By adding sufficient acetonitrile (ACN) to the manufactured compound to dissolve it and form a solution; adding a pre-specified volume of water to the resultant solution and stirring sufficiently to precipitate at least the RDX; separating and drying the precipitate, a pre-specified purity and yield percentage of RDX may be obtained by varying the volume of water added. The process uses relatively environmentally benign recyclable solvents at ambient temperature and pressure reducing both environmental impact and energy costs.
    Type: Grant
    Filed: February 9, 2009
    Date of Patent: August 23, 2011
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Veera M. Boddu, Reddy Damavarapu, Krishnaiah Abburi
  • Publication number: 20100200128
    Abstract: A method of adjusting the yield of a manufactured compound comprising primarily two energetic materials to yield a product comprising primarily one of the two energetic materials. Specifically, embodiments of the present invention provide a method of purifying a compound primarily comprising RDX and HMX to achieve a desired purity of RDX with an acceptable yield percentage. By adding sufficient acetonitrile (ACN) to the manufactured compound to dissolve it and form a solution; adding a pre-specified volume of water to the resultant solution and stirring sufficiently to precipitate at least the RDX; separating and drying the precipitate, a pre-specified purity and yield percentage of RDX may be obtained by varying the volume of water added. The process uses relatively environmentally benign recyclable solvents at ambient temperature and pressure reducing both environmental impact and energy costs.
    Type: Application
    Filed: February 9, 2009
    Publication date: August 12, 2010
    Inventors: VEERA M BODDU, Reddy Damavarapu, Krishnaiah Abburi
  • Patent number: 7304164
    Abstract: 1-Methyl-2,4,5-Trinitroimidazole is synthesized starting from 4-nitroimidazole using stepwise nitration method and further methylation using Dimethylsulphate. It is relatively insensitive to impact and its thermal stability is excellent. The calculated detonation properties indicate that its performance is about 30% better than TATB. It can be prepared easily, with reasonable yield, starting from commercially available Imidazole. Results from impact sensitivity, friction sensitivity, time-to-explosion temperature and vacuum stability tests indicate that it is less sensitive than both RDX and HMX. The good oxygen balance and measured heat of formation data of this material indicate that its propellant performance should be good.
    Type: Grant
    Filed: October 13, 2006
    Date of Patent: December 4, 2007
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Reddy Damavarapu, C. Rao Surapaneni, Nathaniel Gelber, Raja G. Duddu, MaoXi Zhang, Paritosh R. Dave
  • Patent number: 7109359
    Abstract: The invention relates to a novel polyazido compound: 2,2-dinitro-1,3-diazidopropane.
    Type: Grant
    Filed: August 15, 2003
    Date of Patent: September 19, 2006
    Assignee: The United States of America represented by the Secretary of the Army
    Inventors: Paritosh R. Dave, Raja G. Duddu, Reddy Damavarapu, Nathaniel Gelber, Kathy Yang, C. Rao Surapaneni
  • Patent number: 6998485
    Abstract: The compound 3a,8a-bis-azidomethyl-3a,4,8a,9-tetrahydro-3H,8H-bis-[1,2,3]triazolo[1,5-a;1?,5?-d]pyrazine, whose structure is depicted below, is disclosed:
    Type: Grant
    Filed: August 15, 2003
    Date of Patent: February 14, 2006
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Paritosh R. Dave, Raja G. Duddu, Reddy Damavarapu, Nathaniel Gelber, Kathy Yang, C. Rao Surapaneni
  • Patent number: 6965042
    Abstract: The compound 2,2-bis(azidomethyl)oxirane, whose structure is depicted below, is disclosed:
    Type: Grant
    Filed: August 15, 2003
    Date of Patent: November 15, 2005
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Paritosh R. Dave, Raja G. Duddu, Nathaniel Gelber, Kathy Yang, C. Rao Surapaneni, Reddy Damavarapu
  • Patent number: 6841690
    Abstract: This invention relates to a series of novel compounds having the general structures A and B: including 2-azido-2-azidomethyl-1,3-diazidopropane (1), 2-azidomethyl-2-hydroxy-1,3-diazidopropane (2), 2-azidomethyl-2-nitrato-1,3-diazidopropane (3), 2-azidomethyl-2-nitro-1,3-diazidopropane (4), 2,2-dinitro-1,3-diazidopropane (5), methallyidiazide (6), a dimer of methallyidiazide (6), comprising 3a,8a-Bis-azidomethyl-3a,4,8a,9-tetrahydro-3H,8H-bis[1,2,3]triazolo[1,5-a;1?,5?-d]pyrazine (6-Dimer), 1,3-diazidoacetone (7), and 2-Oximido-1,3-diazidopropane (8). Also shown are reaction intermediates of these compounds, including 2,2-bis(chloromethyl)oxirane (9), and 2,2-bis(azidomethyl)oxirane (10).
    Type: Grant
    Filed: August 15, 2003
    Date of Patent: January 11, 2005
    Assignee: The United States of America, as represented by the Secretary of the Army
    Inventors: Paritosh R. Dave, Raja G. Duddu, Reddy Damavarapu, Nathaniel Gelber, Kathy Yang, C. Rao Surapaneni
  • Patent number: 5977418
    Abstract: The invention is a process for regioselective nitration of substituted aromatic compounds and the corresponding reaction products. The reaction is conducted in the presence of a solid zeolite with small pores and with nitrogen pentoxide as the nitrating agent. The reaction products have a very high proportion of para-nitro substituted isomer.
    Type: Grant
    Filed: January 20, 1998
    Date of Patent: November 2, 1999
    Inventors: Reddy Damavarapu, Keerthi Jayasuriya, Thomas J. Kwok
  • Patent number: 5946638
    Abstract: A method is described for the regioselective nitration of substituted aromatic compounds. The reaction is effected by heating the aromatic compound to a temperature within the range of 70-90.degree. C. in the presence of a solid zeolite catalyst and adding concentrated nitric acid to the heated mixture, the concentration of the acid ranging from 90-98%, by weight.
    Type: Grant
    Filed: August 7, 1998
    Date of Patent: August 31, 1999
    Inventors: Keerthi Jayasuriya, Reddy Damavarapu
  • Patent number: 5387297
    Abstract: The compound 2,4-dinitroimidazole is highly insensitive towards impact and its thermal stability is excellent. The calculated detonation properties results indicate that its performance is about 30% better than TATB. It can be prepared easily with good yield starting from inexpensive starting materials. Results from impact sensitivity, friction sensitivity time-to-explosion temperature and vacuum stability tests indicate that 2,4-dinitroimidazole is less sensitive than both RDX and HMX. Its good oxygen balance and measured heat of formation data of this material indicate that its propellant performance is good.
    Type: Grant
    Filed: November 26, 1993
    Date of Patent: February 7, 1995
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Reddy Damavarapu, Keerti Jayasuriya, Theodore Vladimiroff, Sury Iyer