Aenert news. Invention analysis
Liquid organic hydrogen carriers (LOHC) are considered a promising technology for hydrogen transport and storage applications. They include a variety of compounds that can be bound with hydrogen (hydrogenation) so that it can be transported or stored in liquid state without the use of sophisticated compression or cryogenic equipment and released (dehydrogenation) afterwards at the right time and place. Such compounds can include aromatic, heterocyclic, and other organic compositions. Below we provide a brief review of recent inventions disclosing the use of heterocyclic compounds as liquid organic hydrogen carriers, and related technologies.
It should be noticed that in the majority of cases each of the organic carriers, including heterocyclic, requires specific hydrogenation and dehydrogenation conditions, catalyst compositions, has its own hydrogen storage capacity values, etc. That’s why in the pool of reviewed documents collected based on the applicability to heterocyclic compounds, documents can be encountered describing a wide variety of technological aspects of LOHC. The most active applicants by their share in the patenting process for are provided in the chart below:
Applicants share in the intellectual property market, %. Patents, 2019-2023
Value: Market involvement ratio*; Y axis: Ownership ratio; Bubble size: Volume ratio.
*(Market involvement ratio = volume ratio multiplied by ownership ratio, where Volume ratio - share of applicant documents in total number of documents, Ownership ratio - applicant's participation share in total number of documents)
In the revised pool of patents, clear leaders are Sinopec China Petroleum & Chemical Corporation (CN), its affiliated organizations, and Commissariat à l'énergie atomique et aux énergies alternatives (FR).
The largest patent family in the pool of documents examined for this review includes 31 patent documents and is represented by core document AU2020269473A1 (Core document is a base document for which a complete description of the invention is available in generally-accessible patent databases). It is followed by a patent family with core document US7186396B2 (24 patent documents):
Organic hydrogen storage raw material dehydrogenation catalyst, carrier of the catalyst, hydrogen storage alloy, and method for providing high-purity hydrogen / A: AU2020269473A1 / IPC: C22C19/03, C01B3/56, C22C14/00, C22C23/06, C22C30/00 / LIN Wei; YANG Xue; SONG Haitao; SONG Ye; SUN Min; LIU Jun / Sinopec RIPP Research Institute of Petroleum Processing (CN); Sinopec China Petroleum & Chemical Corporation (CN) / Appl. date: 06.05.2020; Publ. date: 12.11.2020 / IP Australia / Core document: AU2020269473A1 / Technology categories: OAC, OHC / Technology elements: Hdh, Hct / Problems: EC, HCHD, LEHD / Technical solution types: M, C / Claims: 16 / Rating: 13;
有机储氢原料脱氢催化剂以及该催化剂的载体、储氢合金、和提供高纯度氢气的方法 / (en:) Catalyst for dehydrogenating organic hydrogen storage raw material, carrier for catalyst, hydrogen storage alloy, and method for providing high purity hydrogen / A: WO2020224584A1 / IPC: B01J23/26 / Lin Wei; Yang Xue; Song Haitao; Sun Min / Sinopec China Petroleum & Chemical Corporation (CN); Sinopec RIPP Research Institute of Petroleum Processing (CN) / Appl. date: 06.05.2020; Publ. date: 12.11.2020 / World Intellectual Property Organization / Core document: WO2020224584A1 / Technology categories: OAC, OHC, OAN / Technology elements: Hdh, Hct / Problems: LEHD / Technical solution types: M, C / Claims: 14 / Rating: 10; the most recent documents in this family were published on 21.10.2022 (CN111892018B) and 18.08.2022 (US20220258133A1).
The following abbreviations are used in the documents hereinbefore and hereinafter: C - Composition; M - Method; OAC - Arene/Aromatic compound ; OHC - Heterocyclic; EC - Ecological problems; HCHD - High cost of hydrogenation or dehydrogenation; LEHD - Low efficiency of hydrogenation or dehydrogenation; Hct - Catalyst; Hdh - Dehydrogenation; Hhg - Hydrogenation.
In the revised pool of patents and patent applications related to the use of heterocyclic compounds as liquid organic hydrogen carriers, the most commonly encountered problems were LEHD - Low efficiency of hydrogenation or dehydrogenation, HCHD - High cost of hydrogenation or dehydrogenation, and EC - Ecological problems.
In the majority of cases, technical solutions disclosed in the patent documents under revision were represented in the form of methods. Compositions were encountered a little less often in the documents, while the number of devices was even smaller.
A portion of the patented solutions was dedicated to the development of novel heterocyclic compounds aimed at solving specific technological problems. In the revision of patent documents disclosing novel heterocyclic compounds used as LOHC, it was discovered that carbazole and its combinations are the most popular heterocyclic carriers the applicants try to employ. Although, in total more than 20 parent carriers were encountered during the process of patent document examination, including quinoline, fluorine, furan, indole.
Mostly, these patented solutions were attributed to the following IPC indices:
| IPC | Share | IPCs assigned |
|---|---|---|
| C01B3/00 | 34.6% | 28 |
| C01B3/02 | 8.6% | 7 |
| C01B3/22 | 7.4% | 6 |
| C01B3/26 | 3.7% | 3 |
| C07D209/86 | 3.7% | 3 |
| C07D213/133 | 3.7% | 3 |
| F17C11/00 | 3.7% | 3 |
| H01M8/06 | 3.7% | 3 |
According to the International Patent Classification, the IPC indices above have the following definitions:
C01B3/00 - Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen; C01B3/02 - Production of hydrogen or of gaseous mixtures containing hydrogen; C01B3/22 - by decomposition of gaseous or liquid organic compounds; C01B3/26 - using catalysts; C07D209/86 - with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to carbon atoms of the ring system; C07D213/133 - Preparation by dehydrogenation of hydrogenated pyridine compounds; F17C11/00 - Use of gas-solvents or gas-sorbents in vessels; H01M8/06 - Combination of fuel cells with means for production of reactants or for treatment of residues.
In recent years, the majority of patent documents were registered in CNIPA (CN), KIPO (KR), WIPO, EPO, and USPTO (US) patent offices.
In the pool of recent patents and patent applications examined for this review, a noticeable group of inventions was aimed at solving the problem of low hydrogen storage capacity of a carrier. Below we provide several examples of recent patent documents that concern this group of technical solutions:
Patent KR102544704B1 granted to Korea Research Institute of Chemical Technology (KRICT) (KR) on 20.06.2023 discloses a hydrogen storage material containing any of the two pi-conjugated pyridine-based compounds shown on the image below. Hydrogenation of such compounds is performed using a Ru, Pt, Pd, or Rh catalyst in the amount of 0.1% wt. -50% wt., at 30°C-250°C and reaction pressure of 10 bar - 200 bar. The dehydrogenation process is performed using a catalyst comprising a group VIIIB metal in the amount of 0.1% wt. -50% wt., at a temperature of 200°C-300°C, and at normal pressure.
The authors of the patent state that the compound of the invention has "…high hydrogen storage capacity per unit weight". It is also stated to have high dehydrogenation rate.
The invention belongs to a patent/application pair that is published in the Korean Intellectual Property Office in 2022-2023.
Images from: KR102544704B1
Patent application US20220024758A1 filed by Yeda Research and Development Co., Ltd. (IL) and published on 06.02.2022 discloses a liquid organic hydrogen carrier comprising an N-heterocycle, a transition metal catalyst or its precursor in an amount of 0.05%-5% w/w, and a weak acid (acetic acid, benzoic acid, carboxypolystyrene, or polyacrylic acid). The N-heterocycle of the invention is substituted or unsubstituted piperidine and its derivatives (preferably, 2,6-dimethylpiperidine or 2-methylpiperidine, or others) or pyridine and is liquid in the range of temperatures between 15°C and 100°C. The following are options for the piperidine or pyridine substitution: "…CH3, CH—CH3, CH—F, CHF2, CF3, OCH3, F, Cl, OH, NH, NH(CH3), N(CH3)2, and CN". The transition metal is selected from: Mn, Fe, Co, Ru, Rh, Pd, Pt, Cu, Ag or their combinations. It is supported on an insoluble matrix, such as "…activated carbon, dried acidic activated carbon, SiO2, BaSO4, BN, γ-Al2O3, or CeO2". The catalyst precursor is selected from Pd(OAc)2, PdCl2, Pd(TFA)2, Pd(acac)2, and Pd2(dba)3. Preferably the catalyst is palladium on activated carbon (Pd/C). The catalyst is used for both hydrogenation and dehydrogenation processes.
The carrier doesn’t contain solvents and is functional under temperatures between 50°C-180°C (preferably, 130°C-180°C) and pressures between 1 bar and 80 bar (preferably, 1.5 bar and 8 bar).
The authors of the invention state that the proposed carrier provides high hydrogen storage capacities. Cost and availability of the compound also stated as the beneficial aspects of the invention.
The application belongs to a family comprising 9 patent documents published between 2020 and 2023 in WO, IL, CN, KR, EP, US, and JP.
Image from: US20220024758A1
Patent application CN114804020A filed by Suzhou Qingde Hydrogen Energy Technology Co., Ltd (CN) discloses a slurry hydrogen storage material prepared from a LOHC, a solid hydride NaAlH, Ni-based and Ti-based catalyst precursors, and a catalyst carrier. The LOHC of the storage material is selected from "…dodecahydro-N-ethylcarbazole H 12 -NEC, octahydro 2-methylindole H 8 -2-MID or octahydro 1-methylindole H 8 -one of 1-MIDs", preferable Ni-based precursor is bis- (1, 5-cyclooctadiene) nickel Ni(COD)2, while for Ti-based precursor the authors propose tetrabutyl titanate Ti(OBu)4. Preferable molar ratio of LOHC, NaAlH, Ni(COD)2 and Ti(OBu)4 is 1: (0.1-1): (0.005-0.01): (0.005-0.01). The proposed catalyst carrier is Al2O3,SiO2, or graphene. The dosage of the catalyst carrier is 2.5 to 5 wt% of the total mass of the two catalyst precursors. The claims of the invention also disclose the method of preparation of the slurry hydrogen storage material.
The authors state that the slurry hydrogen storage material has high storage capacity. Among other beneficial aspects of the invention, the authors mention lower temperature and faster dynamics of operations.
The invention is a single application published in the CNIPA (CN) patent office in 2022.
Image from: CN114804020A
By the Editorial Board
